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Full text of "Natural history."

. N346 

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no. 6 
Jul-Aug 

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What time weakens, nature can strengthen. 

It can add years to life. It can ease the stress of modern living. 
And it can even improve immunity. It's the 'science of life', and as 
old as mankind. It uses self-knowledge and self-care to bring harmony 
to your mind, body and soul — with secrets gathered from leaves, 
flowers, roots, oils and stones. Ayurveda will nourish you. Much 
like Incredible India. 



Incredible Ind 



ny@itonyc.com 



www.incredibleindia.org 



1-800-953-9399 






FEATURES 

COVER STORY 

28 THE SCALY ONES 

Squamata — lizards and snakes — have spread 
to almost every landmass and branched 
into more than 7,200 species. 

LAURIE J. VITT 
AND ERIC R. PI AN KA 



36 FROM FINS TO LIMBS 

Recent fossil discoveries show how 
four-legged land animals evolved 
from fish with finlike paddles. 
JENNIFER A. CLACK 



42 BEYOND THE BIG BANG 

A new cosmic worldview holds 
tli at countless replicas of Earth, 
inhabited by our clones, are 
scattered throughout the cosmos. 

ALEX VILENKIN 




ON THE COVER: 

Defense display of 
leaf-tailed gecko. Madagascar. 
Photograph by Claudio Velasquez. 





DEPARTMENTS 



J 



4 THE NATURAL MOMENT 

Gill of Newt 

Photograph by Rene Krekels 

6 UP FRONT 

Editor's Notebook 

8 CONTRIBUTORS 
10 LETTERS 

12 SAMPLINGS 

News from Nature 

16 FIELD NOTES 

Traveling Green 
Carol Goodstein 

22 LIFE CYCLES 

The Other Kinsey Report 
Peter Del Tredici 

26 BIOMECHANICS 

Keep Me Hanging On 
Adam Summers 

48 BOOKSHELF: 

SUMMER READING 

Science Most Foul 
Laurence A. Marschall 

53 nature.net 

Reptilophilia 
Robert Anderson 

54 OUT THERE 

Deceptive Nebulous Apparition? 
Charles Liu 



58 THE SKY IN JULY AND AUGUST 

Joe Rao 

60 AT THE MUSEUM 

64 ENDPAPER 

Hard Labor at Bear Gulch 
Eugene H. Kaplan 




9 



9 




54 




48 



PICTURE CREDITS: Page 8 

Visit our Web site at 
www.naturalhistorymag.com 



THE NATURAL MOMENT 



UP FRONT 



•< See preceding two pages 

With all their 
hoiling and 
tolling, the witches 
of Macbeth — who 
were cooking with 
"eye of newt, and 
toe of frog" — 
might have been 
improvising by 
tossing newt eyes into their cauldron 
in lieu of a much rarer ingredient: 
the newt's external gills. 

Newts can live for more than 
twenty years, but they sport feath- 
ery gills on their heads or necks 
only for the first few months of 
life, in a so-called larval stage. The 
warty newt (Triturus cristatus), pic- 
tured here with its air-catching 
tiara, probably hatched two or 
three months before photographer 
Rene Krekels saw it. A few weeks 
later the fishy creature would have 
absorbed its gills and gone ashore. 

Newts don't stay on land forever, 
though. Sexually mature adults re- 
turn to the water every spring to 
mate. A pair doesn't embrace; the 
male simply drops a sperm packet in 
the water. If a female deigns to pick 
it up, she will have one of the 
longest labors in the animal world. 
For more than a hundred days the 
pregnant newt lays two or three 
eggs a day, meticulously folding 
them in the tip of a leaf with her 
hind legs. By July, she's finished lay- 
ing, and her firstborn of the season 
are almost ready to join her in leav- 
ing the water behind. 

Krekels had to take great care in 
photographing the warty newt — a 
protected species in Europe. After 
getting a permit from the Dutch 
government, he briefly removed a 
young newt just under four inches 
long from the southern province of 
Limberg and photographed it un- 
derwater on a familiar plant, Elodca 
canadensis. Four days later, the newt 
was released — free to stew naturally 
in its home pond. — Erin Espelie 




Back When 




he lizard version of the Rolling Stones' legendary stuck-out tongue 
on our cover is a reminder of just how ancient these creatures are. 
No, not the Stones. True, the bands tongue logo dates to 1971 , 



primeval by rock n' roll standards. But our lizard's direct ancestors go back 
to the Lower or Middle Triassic, as long as 25 1 million years ago — and, as a 
group, Squamata ("the scaly ones," aka lizards and snakes) are just as much 
with us today as Mick Jagger and Keith Richards. If you, like me, are a big 
fan of squamates, bliss and rapture are at hand: the new exhibition "Lizards 
& Snakes: Alive!" opens July 1 at the American Museum of Natural History 
in New York City, and runs through January 7, 2007. Our cover story, by 
two of the world's leading experts on squamates, Laurie J. Vitt and Eric R. 
Pianka ("The Scaly Ones," page 28), makes evolutionary sense out of the 
extraordinary diversity of lizards and snakes today. 

• • • 

Run the wayback machine another 130 million years or so, to the 
Late Devonian, about 380 million years ago. There you reach an- 
other milestone in the history of life: the arrival of the first four-legged 
creatures on land. In the classic version of the event, memorialized in 
dozens of cartoon images, a frsh sprouts legs and crawls out of the ocean 
onto a deserted beach. But discoveries that made headlines this past April, 
along with meticulous reconstructions that have enabled paleontologists to 
identify new evidence in fossils previously labeled "indeterminate," tell a 
very different story. Jennifer A. Clack, whose work has been at the center 
of the revolutionary new understanding, fills in the story of twenty-five 
years of remarkably productive investigations, in her article, "From Fins to 
Limbs" (page 36). 

• • • 

Now strap yourself in once more and zoom even further into the past, 
to the beginning of time, some 14 billion years ago, when our uni- 
verse began with a big bang. Alex Vilenkin is a leading academic theoreti- 
cal physicist who heads the Tufts [University] Institute of Cosmology, but 
the news he brings about the latest consequences of big-bang cosmology 
("Beyond the Big Bang," page 42) is anything but stuffy. 

According to Vilenkin, "our" big bang is only one of infinitely many 
others, many of which have given rise to exact duplicates of the world we 
know. Like raindrops condensing out of water vapor, each big bang is a 
region of true vacuum — ordinary spacetime — that "condenses" out of a 
substance called the false vacuum, whose boundaries are expanding furi- 
ously And just as the change from water vapor to liquid water dumps 
copious quantities of heat into the atmosphere, the change from false to true 
vacuum releases such prodigious amounts of energy that it generates a big 
bang. Meanwhile, the rest of the false vacuum continues expanding into a 
void of its own creation, racing on like an unstoppable wildfire that began 
from nothing and is now spreading in size by a factor of at least a googol 
(1 ()'"") every thirtieth of a microsecond. If your worldview has been shrink- 
ing of late, if life's minutiae have been crowding out the big picture, 
Vilenkin's article is just what you'll need to regain a cosmic perspective. 

— Peter Brown 



6 



NATURAL HISTORY July/August 2006 



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CONTRIBUTORS 

RENe KREKELS studied biology in the Netherlands before turning 
to nature photography. Krekels has since concentrated on under- 
standing and photographing small creatures, such as the warty newt 
in this issue ("The Natural Moment," page 4). He particularly en- 
joys freeze-framing an insect in flight — a butterfly, a blue-winged 
grasshopper, a cockshafer — or a frog in mid-dive, with his high- 
speed camera and a macro lens. 



Both career devotees of lizards and snakes, 
LAURIE J. VITT and ERIC R. PIANKA ("The Scaly 
Ones," page 28) have collaborated in recent years, 
most notably in co-authoring Lizards: Windows 
to the Evolution of Diversity (University of Califor- 
nia Press, 2003), the winner of a number of 
awards. Vitt is George Lynn Cross Research Pro- 
fessor and Curator of Reptiles at the Sam Noble 
Oklahoma Museum of Natural History, and a professor of zoology at the Uni- 
versity of Oklahoma, both in Norman. He is interested in how the evolution- 
ary history of lizards and snakes has influenced their present-day ecology and be- 
havior. Pianka, who is Denton A. Cooley Centennial Professor of Zoology at 
the University of Texas at Austin, specializes in the study of monitor lizards. Mon- 
itors were the subject of his most recent article for Natural History (with Samuel 
S. Sweet), "The Lizard Kings" (November 2003). 

In her study of the evolution of four-legged animals from their 
fish ancestors, JENNIFER A. CLACK ("From Fins to Limbs," page 
36) has collected fossils in Greenland, Scotland, and England, 
and examined specimens from museum collections around the 
world. Clack earned her Ph.D. in paleontology from the Uni- 
versity of Newcastle upon Tyne and joined the University Mu- 
seum of Zoology in Cambridge as a curator. She is a professor 
and curator in vertebrate paleontology at the University of Cambridge. Her 
book about the origin of tetrapods, Gaining Ground, was published in 2002. 

ALEX VILENKIN ("Beyond the Big Bang," page 42) is a theoret- 
ical physicist who has conducted research in cosmology for more 
than twenty-five years. His most recent research has focused on 
the possible existence of multiple universes and other implica- 
tions of eternal cosmic inflation, one of the novel ideas he has 
introduced. His new book, Many Worlds in One (Hill and Wang), 
from which our feature is adapted, chronicles firsthand the birth 
of a new cosmology that incorporates many of his influential theories. Vilenkin 
emigrated to the United States from the U.S.S.R. in 1976, receiving his Ph.D. 
the following year from the State University of New York at Buffalo. He is a pro- 
fessor of physics at Tufts University in Medford, Massachusetts, and serves as di- 
rector of the Tufts Institute of Cosmology. 





PICTURE CREDITS Cover: CCLiudio Vclasqucz/naturepl.com; pp. 4-5: ©Rene KrekeLs/Foto Natura; p. 10: Cartoon by Dolly Set- 
ton; p. 12(top): ODcan A. Hcndrickson; p. 12(mjddle): ©Alexander Kupfer; p. 12(bottom): CMarrin Harevy Peter Arnold. Inc.; p. 



Sc 



l3(top 



Eht): 



I c\ tli 



Mark Pavne-Gilliiatuicplconi; p. 13(bottom): Courtesy of Historic 
The Jewish National and University Library/historic-cities. huji.ac.il; p. 
ilu'u Study Team; p. 1 4(bottoni): ©Mark Taylor/naturepl.com; pp. 22- 
)ld Arboretum of Harvard University; p. 23: ©The Kinsey Institute: pp. 
naturepl.com; p. 30: ©Eric Pianka; p. 31: Illustrations by Patricia J. 
p. 33(bottom): Illustration by Ian Worpole; pp. 34-35: ©NHPA/ 
Stephen Dalton; pp. 36-37: Illustration by Advanced Illustration; p. 38: Map by Chris Scotese/Paleomap Project/www.scotese.com; p. 
39; CJennifcr A. Clack/ Ahlberg et al. /Nature p. 40-41: CThe Geological Museum. Copenhagen; pp. 42-43 ©Ace Gallery. L.A: pp. 
456V46: Illustrations by Advanced Illustration; p. 48: t Rucdigcr Knobloch/A.B./zcfa/Corbis; pp. 55: ©NASA/JPL; p. 64: Richard 
Lund/CCarnegic Museum of Natural History. 



13(top left): Denis Crawford/Grapl 
Cities Research Project/The Hebrew Universir 
14(top): ©Stan Hart, Craig Young. Hubert Stau. 
23(background): ''Gray Herbarium Archives; p. 
26-27: Illustrations by Tom Moore; pp. 28-29 
Wynne; p. 32: CNiranjati Sam; p. 33(top): ©Stew 



mm 



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NATURAL HISTORY July/August 2006 



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LETTERS 



Coal Wars 

Jeff Goodell ["Cooking the 
Climate with Coal," 05/06] 
identifies two factors con- 
tributing to our increased 
reliance on coal, namely the 
self-interest of the coal in- 
dustry and the denial of 
global warming. But he fails 
to note an equally important 
cause: the single-minded 
focus of the environmental 
movement on opposing nu- 
clear power, in the process 
giving coal what amounts 
to a pass. That's ironic, be- 
cause nuclear power, what- 
ever its faults, emits essen- 
tially no greenhouse gases. 

It's time for environ- 
mentalists to rethink their 
priorities and make stabi- 
lizing the global climate 



job number one. 

John Andrews 

Sag Harbor, New York 

The objectivity of any arti 
cle purporting to 
deal with energy 
that dismisses nu- 
clear power in one 
sentence as "uncer- 
tain" is open to 
skepticism. It, as 
Jeff Goodell s arti- 
cle does, it then 
goes on to embrace 
the truly unproven 
technology of "se- 
questering" 7 bil- 
lion tons of C0 2 
annually (adding 5 
billion tons of oxy- 
gen to the 2 billion 
tons of carbon in 







over 






I 


/ 






s 












{ 














J 




Paramecium 


in mid life c 


risis 



the coal used by the U.S. 
and China alone), it is not 
worth reading. 

Nuclear power generates 
zero C0 2 and negligible 
waste volume, 
compared with 
any fossil-fuel 
technology. A ra- 
tional environ- 
mentalist must fa- 
vor building new- 
generation nuclear 
power plants to re- 
place existing fos- 
sil-fuel capacity as 
rapidly as possible. 
That's the envi- 
ronmental Man- 
hattan Project that 
would actually 
work to reduce 
the contribution 



of C0 2 to global warming 
significantly in our life- 
times, and without major 
economic dislocation. 
Richard B. Mott 
Ringoes, New Jersey 

Jeff Goodell's thought- 
provoking commentary still 
failed to mention the great- 
est threat of coal-combus- 
tion emissions; uncontrolled 
coal mine fires. According 
to the Pittsburgh Post Gazette 
(February 15, 2003), un- 
controlled coal mine fires 
in China "make a big, hid- 
den contribution to global 
warming through the 
greenhouse effect. Each year 
they release 360 million 
tons of carbon dioxide into 
(Continued on page 50) 



NATURAL HISTORY July/August 2006 




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SAMPLINGS 



Hidden World in the Desert 



Although the word "oasis" might conjure im- 
ages of gently swaying palm trees and pools 
of sparkling water, those rare watery refuges 
in the desert offer more than just respite for 
parched travelers. They're also complex eco- 
systems. According to a recent study, a par- 
ticularly complex patch called the Cuatro 
Cienegas Basin (CCB) lies in the midst of 
Mexico's windswept Chihuahuan Desert. It 
covers 325 square miles and includes a di- 
verse array of aquatic habitats, including 
lakes, marshes, ponds, springs, and streams. 
Besides hosting more than seventy endemic 
species of aquatic vertebrates, the CCB shel- 
ters a unique community of microorganisms, 
relics of the oasis's ancient past. 

Led by Valeria Souza, an evolutionary 
ecologist at the National Autonomous Uni- 
versity of Mexico in Mexico City, a team of 
investigators sequenced microbial DNA and 
discovered thirty-eight previously unknown 
microbial lineages in the CCB's waters. Sur- 

No Laughing 
Matter 

To be top dog in a society of spotted 
hyenas, you've got to be a real bitch. Fierce- 
ly competitive scavengers, hyenas have no 
truck with the usual mammalian rules of 
dominance: females control the social hier- 
archy with an aggressiveness normally ex- 
erted only by males. Whether in females or 
males, aggression means androgens — male 
sex hormones, such as testosterone — and 
plenty of them. Biologists have known that 
prenatal exposure to androgens (indepen- 
dent of an individual's genetic endowment) 
fosters lifelong reproductive success in 
birds. Now, Stephanie M. Dloniak and Kay 




Spotted hyena mothers pass down social rank, 
along with hormones, to their cubs. 



prisingly, the closest rela- 
tives of half the lineages 
are marine species, even 
though the CCB has been 
separated from the ocean 
for tens of millions of years 
Souza and her team also 
discovered closely related 

microorganisms in valleys 

^ ■ i ,i ,~^r> ■ i Cuatro Cieneqas 

outside the CCB — evidence 

of hydrological connections 

between the oasis and its surroundings. 

In recent years the CCB, a federally des- 
ignated "area for the protection of flora 
and fauna," has come under increasing 
pressure, particularly from the irrigation of 
nearby alfalfa fields for cattle, which may 
drain the aquifers that supply the oasis. 
Souza and her group hope their findings 
help promote more stringent measures to 
conserve the region's water. (PNAS 1 03: 
6565-70, 2006) — Nick W. Atkinson 



E. Holekamp, wildlife biologists with Michi- 
gan State University in East Lansing, and 
one of their colleagues have shown that 
prenatal androgen exposure in at least one 
mammal — the hyena — may translate into 
access to food and mates. 

Androgens, like other hormones, pass 
from the blood of a pregnant female hyena 
through the placenta to her developing fe- 
tuses. By studying fluctuations in androgen 
levels during pregnancy, the biologists dis- 
covered that during the late stages, domi- 
nant females have higher androgen levels 
than do females further down the pecking 
order. That extra androgen boost in the 
womb leads to increased aggressiveness 
and mounting behavior in cubs of high-sta- 
tus females, traits that should give the 
cubs a competitive edge later in life. 

Practice at mounting is particularly 
important for male hyenas, say the 
biologists. The female mates and 
gives birth through her uniquely 
masculinized genitalia — an elongated 
clitoris that resembles a penis. Mating 
(not to mention birthing) is thus ex- 
tremely difficult. So, the more mount- 
ing males do as cubs, the more suc- 
cessful at mating they're likely to be 
as adults. {Nature 440:1 190-3) 

—N.W.A, 




Basin is an oasis for microorganisms. 

Oh, the Trials 
of Motherhood 

When it comes to mothering, some caecil- 
ians willingly give the skin off their backs. 
Caecilians are tropical, soil-dwelling, legless 
amphibians that range in length from four 
inches to more than four feet. They look like 
giant earthworms. Alexander Kupfer, a 
biologist at the Natural History Museum in 
London, captured and then videotaped 
twenty-one females of the Kenyan species 
Boulengerula taitanus, along with broods of 
between two and nine young. Kupfer and his 
colleagues were amazed to see the young 
literally munching 
on Mom. 

A newly 
hatched B. tai- 
tanus has teeth 
specially suited 
for peeling off its 
mother's outer 
layer of skin — her 
epidermis. Mom 
doesn't mind; in 
fact, she's a will- 
ing participant. 
While nursing, her epidermis grows to twice 
its normal thickness and develops modified 
cells full of nutritious fats and proteins. 

This newly recognized form of parental 
care joins a long list of ways parents give 
of their own bodies to feed their young. 
Female mammals, of course, secrete milk. 
Some female frogs and fishes produce unfer- 
tilized eggs for their hungry young to eat. 
But males, too, can be generous: flamingos, 
emperor penguins, and pigeons of both gen- 
ders produce "bird milk" — cells that slough 
off the internal lining of the crop or esopha- 
gus — and certain cichlid fishes, male as well 
as female, secrete nutritious mucus through 
their skin. (Nature 440:926-9, 2006) 

— Stephan Reebs 




Worms? Think again: 
Boulengerula taitanus is 
an amphibian with 
strange nursing habits. 



NATURAL HISTORY July/August 2006 



Beware the 
Toxic Toad! 

Evolution has a way 
of fighting back. No- 
where is that process 
more visible than in Aus- 
tralia, where one species of snake 
is mounting a defense against the cane 
toad, an ever-encroaching menace. The 
toad, which can weigh three pounds, was in- 
troduced in 1935 in an early attempt at bio- 
logical control of sugar cane's insect pests. 
Alas, that well-meaning act unleashed an 
ecological disaster. Cane toads are toxic 
enough to kill a person. In addition to de- 
vouring native insects and small vertebrates 
they've been decimating would-be toad 
predators, including certain lizards, marsupi- 
als, and snakes. 




Ben L. Phillips and 
Richard Shine, biologists at the University 
of Sydney, are studying the impact of cane 
toads on Australia's native red-bellied black 
snake {Pseudechis porphyriacus). In a series 
of experiments, Phillips and Shine have 
shown that certain populations of the 
snake have evolved not only to avoid the 
toads, but also to resist their toxins (to a 
degree). Those characteristics are hard- 
wired into the snake's genome. The longer 
a snake population has been exposed to 



Red-bellied black snake 
and cane toad 



cane toads, the more likely its members are 
to avoid eating the toads, and the greater 
their resistance to toad toxins. 

Does the snake's evolution offer a glim- 
mer of hope for conserving Australia's 
native species? Perhaps. But Phillips and 
Shine have also shown that cane toads at 
the advancing front of an invasion are evolv- 
ing longer legs, which enable them to dis- 
perse ever more quickly. {Proceedings of the 
Royal Society B, doi10.1098/rspb.2006. 
3479, 2006) —N.W.A. 



Proto-Alexandria Fog Lifts on Ozone 



Alexander the Great founded the Egyptian 
city of Alexandria in 331 B.C. Some scholars 
say the spot had been vacant land, but given 
its natural harbor and its proximity to the Nile 
delta, it should have attracted earlier settlers. 
Indeed, ancient texts suggest the presence 
of a prior community, called Rhakotis, but 
there is little archaeological evidence 
to corroborate those accounts. 

To settle the debate, Alain Veron, 
an environmental chemist at Paul 
Cezanne University in Aix-en- 
Provence, France, and four col- 
leagues extracted cores of sediment 
from Alexandria's old harbor. They 
determined the age of each layer of 
sediment by carbon-dating the 
seashells and corals trapped within it. 
Then they measured the amount of 
lead in each layer, because lead is a 
telltale sign of advanced human activ- 
ity. Since ancient times, people have used 
lead for glassmaking, plumbing, shipbuild- 
ing, and statue casting — and also polluted 
their harbors with it. 

As expected, the investigators' analysis 
shows a sharp increase in industry around 
the time Alexandria was founded, and ele- 
vated levels for hundreds of years there- 
after. (In fact, the lead levels in Alexandria's 
ancient harbor were twice what they are in 
modern industrial estuaries.) But the analy- 
sis also shows two small, earlier spikes. The 
first dates to about 2300 B.C., when many 



Way up in the stratosphere- — about ten to 
thirty miles above Earth — ozone protects 
our planet from damaging ultraviolet radia- 
tion. In the troposphere, though — below 
about ten miles — that same molecule is a 
potent greenhouse gas. Its exact effect on 




Alexandria, Egypt, depicted in a sixteenth- 
century German map 

settlements sprang up in the Nile delta. The 
second took place about 900 B.C., at the 
end of the prosperous twentieth Egyptian 
dynasty, just before Assyrians, Nubians, 
and Persians got into the habit of invading 
Egypt and sacking its towns. Rhakotis may 
not have been much to look at by the time 
Alexander arrived, but it nonetheless 
appears to have had a long history of 
settlement. [Geophysical Research Letters 
33:L06409, 2006) —S.R. 



global warming has remained elusive, but 
a new study paints the clearest picture 
yet of how ozone (0 3 ) has affected 
Earth's climate during the past century. 

Tropospheric 0 3 forms mainly from 
reactions among certain emissions from 
fossil-fuel combustion, sunlight, and 
water. With the help of computer simu- 
lations, a team of climate scientists led 
by Drew Shindell of NASA's Goddard 
Institute for Space Studies in New York 
City found that tropospheric 0 3 levels 
rose by about 40 percent between 1890 
and 1990, but not in a uniform way. 

Levels of 0 3 rose gradually before 
the 1950s but more quickly thereafter, 
thanks to surging industrialization 
across the developed world. Higher 0 3 
levels prevail in regions surrounding in- 
dustrial centers and in areas prone to 
forest fires, where substantial quantities 
of its precursor chemicals are released. 
Consequently, there's more surface 
warming in those regions. Increased tro- 
pospheric ozone, Shindell's team dis- 
covered, thus led to a greater rise in 
temperatures in the more industrialized 
Northern Hemisphere than in the less 
industrialized tropics, and a greater rise 
in the tropics than in the Southern 
Hemisphere. And watch out, Arctic 
ice: 0 3 is an exceptionally powerful 
warming agent over reflective surfaces. 
(Journal of Geophysical Research 111: 
D08302, 2006) —N.W.A. 



July/August 2006 NATURAL HISTORY 



13 



Soap in Your 
Vegetables? 

Worried about germs? To calm your fears, 
modern corporations have added antimi- 
crobial compounds to many household 
products, including cosmetics, soaps, and 
toothpastes. One such compound is tri- 
clocarban (TCC). About a million pounds 
of it are manufactured each year in the 
United States, and at high doses, it's toxic 
to people. Once used, the compound 
gets flushed down your plumbing. Where 
does it go from there? 

To understand the fate of TCC, 
Jochen Heidler, Amir Sapkota, and Rolf 
U. Halden, environmental health scien- 
tists at Johns Hopkins University in Balti- 
more, monitored the chemical's journey 
through a large wastewater treatment 
plant in the eastern U.S. They've got 
both good news and bad news to tell. 

The good news is that the plant re- 
moved 97 percent of the TCC from the 
wastewater it received, and released only 
3 percent directly into local bodies of 
water. The bad news is that the TCC re- 
moved from the water gets 
trapped in the plant's reservoirs 
of sludge, where it seems impervi- 
ous to degradation by bacteria. 
All told, the chemists detected in 
the sludge about 76 percent of 
the TCC that had originally en- 
tered the plant. That could be 
problematic: sludge is often recy- 
cled as fertilizer, and that could 
lead to the accumulation of TCC 
in agricultural fields. From there, 
the antimicrobial might enter the 
food supply. TCC in the environ- 
ment might also give rise to anti- 
biotic-resistant bacteria. 

The same team recently developed a 
test for environmental traces of TCC, 
then sampled waters upstream and down- 
stream of nine wastewater treatment 
plants across the country. All of the down- 
stream and more than half of the up- 
stream bodies of water showed traces of 
the chemical. But it's still not clear whether 
the stuff accumulates and eventually 
reaches harmful levels in nature. {Environ- 
mental Science & Technology, doi:10. 
1021/es052245n, 2006; Environmental 
Research, in press, 2006) — S.R. 



Death Zone 

In a remote tract of the 
southwest Pacific, thirty 
miles east of the eastern- 
most island in the Samoan 
archipelago, a volcanic 
seamount rises nearly 
15,000 feet from the ocean 
floor, higher than Mt. Shasta 
in California. At the center 
of the seamount is a cav- 
ernous crater, from which, Cutthroat eels 
in just the past four years, a 
towering, thousand-foot-high cone of hard- 
ened lava has emerged. 

The crater floor is a death zone, accord- 
ing to Hubert Staudigel, a marine geogra- 
pher at the Scripps Institution of Oceanog- 
raphy in La Jolla, California, and his col- 
leagues. Recently they've been visiting the 
seamount, 3,300 feet below the ocean's sur- 
face, and have observed numerous car- 
casses of crustaceans, fish, and squid on the 
crater floor. The investigators think that 
strong currents circulating around the 
seamount wash hapless midwater creatures 
into the crater's depths; once there, the ani- 



swarm near their deep-sea volcanic abode. 

mals perish because of toxic emissions from 
hydrothermal vents. 

But one creature's hell can be another's 
paradise. Bright red sea worms inhabit the 
crater, feeding on the bacteria that thrive 
on the rotting remains. Near the cone's 
summit lives an army of cutthroat eels, 
Dysommina rugosa, a species previously 
known only from trawled specimens. The 
eels gorge on shrimp carried in by the same 
currents that occasionally wash some of 
their comrades into the toxic trap below. 
(PNAS 103:6448-53, 2006) 

—S.R. 




Keas: nosy by nature 

Avian Einsteins 

To test the intelligence of birds, etholo- 
gists often present them with a piece of 
food dangling from the end of a string. To 
get the food, a bird perched on a branch 
must reach down, grab the uppermost 
segment of string in its beak, pull the 
string up, pin it between foot and branch, 
reach down, grab the next segment, pull 
that up, and so on. Devilish variations of 
the test include forcing the birds to choose 
between two strings, which may be 
crossed or pulled to one side by wire. For 



the past decade, the champion string- 
pullers have been ravens. But recently, 
keas have taken over the lead. 

Keas are inquisitive, olive-green parrots 
that live in the mountains of New Zealand. 
(They occasionally strip windshield wipers 
off cars, seemingly just for the fun of it.) 
Seven keas reside in captivity at the Konrad 
Lorenz Institute for Ethology in Vienna. This 
septet never saw a string in their lives until 
Dagmar Werdenich and Ludwig Huber of 
the University of Vienna submitted them to 
the string-pulling task. Yet the keas figured 
out the problem in a matter of seconds on 
their very first try, faster than ravens ever 
have. Only one fledgling, which was still 
developing its beak-foot coordination, 
failed the test. 

In birds, feats of intelligence often occur 
in species that use tools or cache food, as 
ravens do. Keas, however, do neither. But 
they're gregarious, and intelligence seems 
to be useful to animals that operate within 
social networks. Known as the "social func- 
tion of intellect," that hypothesis has so far 
been applied mainly to primates. Could it 
also be valid for birds? (Animal Behaviour 
71:855-63,2006) —S.R. 



\4 



NA'IUHAI HISTORY July/August 2006 



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NATURALIST AT LARGE 

Traveling Green 

Tourists who want to vote with their pocketbooks 
for sustainable practices can consult networks that certify 
ecotourist operators. But who certifies the certifiers? 



By Carol Goodstein 

The palm-lined shores of Bocas 
del Toro — a group of small is- 
lands on the Caribbean side of 
northwest Panama — attract a bountiful 
assortment of species. The waters are re- 
splendent with hundreds of tropical fish, 
colorful sea stars, spiny lobsters, and mas- 
sive coral formations. Four species of 
sea turtles, all endangered, come ashore 
every year to nest, laboriously pulling 
themselves onto the beaches. 
Also here, on the sandy 
grounds, is the species that 
sets itself apart: the human, 
both visitor and inhabitant. 

Ten years ago few foreign 
visitors knew anything about 
the abundant life-forms on and 
around these beaches. Then, 
word of mouth and a booming 
ecotourism industry that is 
transforming Latin America 
brought thousands of tourists to Bocas 
del Toro. The tourists come to see the 
sea turtles nesting, snorkel among the 
blooming coral reefs, and meet the lo- 
cals. Yet, if the very presence of tourists 
starts to disrupt the fragile ecosystem 
they came to see, everyone — native in- 
habitants, tourists, wildlife, the environ- 
mental movement as a whole — loses. 

One native of Bocas del Toro, a man 
named Milford Peynado, was well ac- 
quainted with those concerns five years 
ago when he began to build some sim- 
ple hotel rooms next to his house on 
Carenero Island. The rooms he built are 
not far from a group of rustic fishermen's 
homes and a smattering of other hotels 
and restaurants along a narrow beach. 
For years Peynado relied on fishing for 



his livelihood. But a steady decline in 
crab, lobster, and octopus populations 
forced him and a number of other is- 
landers to look for alternative incomes. 
A welcome influx of tourist dollars 
brought wealth to the community, but 
resident entrepreneurs were still wary of 
protecting their slice of island paradise. 




TOURISM 



So Peynado and fellow residents band- 
ed together to stave off what could be- 
come the high price of popularity. The 
idea was that sustainable tourism could 
benefit all of Bocas del Toro s inhabi- 
tants, including the migrant sea turtles, 
but only if it was approached as a long- 
term commitment — that is, only if it 
was designed to be sustainable. 

Tourism ranks among the worlds 
largest and fastest-growing indus- 
tries. According to the UN World 



Tourism Organization (UNWTO) — 
which serves as a global forum for pol- 
icy issues affecting tourism — more 
than 800 million people travel inter- 
nationally and domestically each year. 
Some observers predict that tourist ar- 
rivals will grow by 4 percent or more 
a year in the next two decades. Such 
growth could bring the total close to 
a billion travelers by 2010. 

Unregulated, all that globetrotting 
can overwhelm the resources at natur- 
al sites; uncontrolled ecotourism may 
displace local people, threaten wildlife 
by introducing non-native species, and 
pollute the area. Moreover, evidence 
suggests that tourists are being drawn 
in increasing numbers to the hotspots 
of biodiversity — the very places that 
need protection the most. 

Yet tourism can also be a powerful 
conservation tool. Conservation and 
wildlife protection often require direct 
financing, which can be extraordinar- 
ily expensive. In Rwanda, for instance, 
which is still recovering from years of 
genocide, tourism has 
helped protect the 
mountain gorilla pop- 
ulation and its habitat. 
Tourists visiting Pare 
National des Volcans, 
about a ninety-minute 
drive from Kigali, pay 
$375 each to accompany a local guide 
who can track lowland gorillas for a day. 
The national park generates $1 million 
annually for the Rwandan govern- 
ment, which is used to support the 
management and operation of the 
country's protected areas. For the Gala- 
pagos Islands, tourism generates as 
much as $38 million a year. Belize levies 
a conservation tax of $3.75 on every 
foreign visitor who leaves the country, 
generating about $750,000 a year. A 
percentage of that money, too, goes in- 
to a national trust and back into the 
country's natural areas. 

Of course, compared with the cap- 
itals of world tourism — think of Italy 
or Greece — those are paltry receipts. 
Yet it would be a mistake to conclude 
that for countries such as Belize, 
Ecuador, or Rwanda tourism is unim- 



6 



NATURAL HISTORY July/August 2006 



portant. In fact, tourism is a primary 
source of foreign-exchange income. 
Moreover, the potential for the growth 
of ecotourism in those countries is 
enormous, albeit still unrealized. 
Those points only highlight the need 
for the countries to promote "travel- 
ing green." A recent survey by an on- 
line travel agency in the United King- 
dom known as responsibletravel.com 
found that 80 percent of tourists would 
be more likely to book with a tour op- 
erator that has a so-called green poli- 
cy in place. People who want to trav- 
el to pristine locations do not want to 
be responsible for causing damage, and 
they often seek out tourism operators 
that advertise "environmental aware- 
ness." Yet what controls are in place for 
would-be travelers and responsible 
business owners to verify claims that 
sustainable tourism is in place? 

In 1992 a UN conference on the en- 
vironment, the so-called Earth Sum- 
mit, was held in Rio de Janeiro. The 
conference spawned a pact known as 
Agenda 2 1 , which called for sustainable 
development and in turn led to a pro- 
fusion of new certification systems. 
The vast disparity that grew up among 
those systems eventually prompted the 
organization I am associated with, the 
Rainforest Alliance, to study whether 
universal standards could be set for sus- 
tainable tourism. We are now working 
with the International Ecotourism So- 
ciety to build a global network that pro- 
motes higher standards of tourism. 

Programs that certify sustainable 
practices often work much like the 
"star" ratings, which companies such as 
Michelin or Mobil award when they 
publish their travel guides to hotels and 
restaurants. They can be subjective or 
rigorous, expansive or narrow. In the 
more reputable programs, second- or 
third-party assessors inspect business es- 
tablishments that hope to be certified. 
Their seals of approval are granted on- 
ly temporarily and must be re-earned 
every few years, as technology, the en- 
vironment, and tourist traffic evolves. 

Hence the very process of certifica- 
tion acts not only as a tool for measur- 



ing and enforcing com- 
pliance with pre-estab- 
lished criteria, but also 
for promoting them. 
Travel surveys and plain 
economic demand de- 
monstrate that tourism 
businesses have an eco- 
nomic interest in being 
listed as green. So long as 
the certification process 
itself is incorruptible, 
certification offers the 
incentive for substantial 
economic reward to 
businesses for good be- 
havior. By setting up ap- 
propriate certification 
criteria, some of the cer- 
tification programs — 
which go by such names 
as Blue Flag, Green Deal, 
and Green Globe — are 
making their own con- 
certed efforts to control 
unchecked development 
and foster responsibility 
among so-called eco- 
establishments [see sidebar 
on tliis page for a few example. 



EXAMPLES OF CERTIFICATION 
CRITERIA OR PROTOCOLS 




Beaches and marinas in 
Canada, the Caribbean, 
Europe, and parts of 
Africa 

www.blueflag.org 



Sites must have an 
emergency plan in place for 
pollution accidents, and be 
available for unannounced 
water-quality inspections. 



BLUE FLAG 



eco 

CERTIFIED 



Accommodations, tours, 
and attractions in 
Australia 

www.ecotourism.org.au 



Third parties often do 
onsite, random audits; 
certification must be 
renewed every three years. 





Tour operators, hotels, 
and restaurants in 
Guatemala 
www.greendeal.org 


A team of independent 
auditors looks at 
environmental practices and 
cultural relations. 




Tour operators, 


Starts with "benchmark" 


® 


restaurants, resorts, 


standards that must be met 


and more, around 


before full certification 




the world 


(signaled by a checkmark 




www.greenglobe.org 


through the globe icon). 




Accommodations in 
Denmark, Estonia, 
France, Greenland, 
and Sweden 
www.green-key.org 


Inspects energy 
consumption and chemical 
use; sets individualized goals 
for each site. 



Ecotourist organizations around the world — such as the ones 
symbolized by the logos above — feature a bewildering variety of 
certification criteria and protocols to ensure compliance. Some 
are banding together to standardize the meaning of "green. " 



One criterion common to most 
meaningful certification pro- 
grams concerns the use of water. Big re- 
sorts consume as much as 300 gallons 
of water per guest per day. Any hotel 
that can cut that consumption takes a 
major step toward a sustainable enter- 
prise. Stanley Selengut, who has oper- 
ated a Maho Bay resort on Saint John 
in the U.S. Virgin Islands since 1974, 
has installed low-flush toilets, pull- 
chain showers, and low-flow faucets; 
his average has tumbled to twenty-five 
gallons of water per guest per day. 

One benefit of the focus on sustain- 
ability, Selengut says, is that each step 
in that direction "has led us to new op- 
portunities and new innovations with 
unforeseen applications." He started his 
hotel with eighteen tentlike cottages on 
elevated walkways, designed so as not 
to disturb the local vegetation on the 
steep hillside or cause damage to the 
reef just below. No construction roads 



were created, few trees were removed, 
footings were dug by hand, and use of 
heavy machinery was minimized. 

Once the resort was operating, Se- 
lengut realized he could enhance the 
environment with its by-products. He 
began to put "graywater" — wastewater 
from washing machines and the like that 
does not need to be chemically treat- 
ed — compost, and recyclable materials 
to good use. "Our use of graywater has 
not only enabled us to cut down on our 
use of a precious island resource," he 
says. "But it's also led us to a compre- 
hensive system of site restoration" — in- 
cluding the reintroduction of native 
plants, natural methods of insect con- 
trol, and wildlife management. 

Although sustainable tourism has 
been adopted primarily by small, in- 
dependent operators, a number of the 
world's larger tourism companies, 
from hotels to tour operators, are also 
restructuring their management and 
operations. The aim is to reduce the 
consumption of water, energy, and 



July/August 2006 NATURAL HISTORY 



1 




other resources, and to improve the 
management of waste. In Jamaica, for 
instance, dozens of hotels — from small, 
family-run operations to Sandals, the 
islands largest hotel chain — are 
now Green Globe 
certified. 

There is nothing 
mystical about the proc- 
ess. To get certification 
from such an organiza- 
tion, hotels can make 
headway just by eliminat- 
ing leaks, using water-sav- 
ing toilets and showers, 
turning sprinklers on in the 
morning or evening instead 
of in the evaporative heat of 
the day, and avoiding clean- 
ing products that contain 
bleach. And in meeting those require- 
ments, the hotels are not only able to 
do good for the environment, but also 
for the bottom line. Small hotels, which 
typically spend between $700 and 
$1,500 to make the needed improve- 
ments, usually find that the changes pay 
for themselves in less than a year. 

When Peynado built his hotel in 
Bocas del Toro, he believed in 
sustainable tourism, but he wasn't sure 
how to put it into practice. Last year he 
and other business owners from his area 
took part in a conservation training ses- 
sion hosted by the Rainforest Alliance. 
As of April 2006, more than 2,000 
people had attended Alliance work- 
shops throughout Belize, Costa Rica, 
Ecuador, Guatemala, and Panama. The 
workshops are held to show the own- 
ers how to cut costs and mitigate the 
negative eftects of their hotels on the 
environment by reducing energy and 
waste. Alliance workshops also intro- 
duce many business owners to sources 
of funding that can help them meet 
those goals. For example, participants 
are encouraged to apply for "green 
funds" such as Verde Ventures, a $7 mil- 
lion investment fund managed by Con- 
servation International, a nonprofit en- 
vironmental organization, which offers 
grants to programs that benefit the con- 
servation of biodiversity. 



Ten years ago an American expatri- 
ate named Eddie Ryan bought a patch 
of rainforest along Costa Rica's south- 
ern coast near Puerto Viejo. There he 
built a small hotel called Costa 
de Papito, and now he is reap- 
ing the benefits, because Costa 
Rica has come to be consid- 
ered a mecca for sustainable- 
tourism development. Ryan, 
a regular at Rainforest Al- 
liance workshops, asked his 
guests to recycle garbage, 
turn otf lights, and reuse 
their towels. Many of them 
return home converted by 
his missionary zeal. Local 
neighbors, too, seem to be 
picking up on the envi- 
ronmental doctrine. And Costa Rica's 
lead has spread to other Latin Ameri- 
can countries and around the world. 

Helping consumers choose among 
the hundreds of certified options 
remains a challenge. Every certification 
program seems to have its own set of 
criteria, and the degree of compliance 
with them varies widely. Some hotels 
consider themselves "green" if they put 
a sign in their guests' bathrooms asking 
them to reuse the towels. But slowly, in 
the past few years, a common language, 
along with minimum standards, has 
begun to emerge as regional networks 
have grown up. 

The regional approach has devel- 
oped as people realized that what is 
needed to make an environmentally 
sustainable and socially responsible en- 
terprise varies enormously with loca- 
tion. What might work for a business 
in, say, the Gobi desert, might be to- 
tally inappropriate in a Guatemalan 
rainforest or in the mountains of Bo- 
livia. The most highly developed re- 
gional networks are VISIT and ECO- 
TRANS in Europe and the Sustainable 
Tourism Certification Network of the 
Americas (STCNA). (The Rainforest 
Alliance currently serves as the secre- 
tariat for STCNA.) Strong, fledgling ef- 
forts are also underway in Africa and 
in the Asia-Pacific region. 

In September 2005 STCNA ratified 



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a comprehensive set of eighty-eight 
criteria for sustainability. They aim, in 
general, at reducing waste, water use, 
and energy use; protecting the envi- 
ronment; and providing education and 
economic benefits to local communi- 
ties. The acceptance of those criteria 
across the wide STCNA network will 
be an enormous help to travelers in 
evaluating hotels, lodges, and other 
businesses. The network is also estab- 
lishing an ad hoc committee with rep- 
resentatives from other regions around 
the globe to standardize the criteria; it 
is working with ECOTRANS to es- 
tablish an international comparison of 
certification requirements that extends 
beyond the Americas. Those partner- 
ships and networks will enable small 
hotels such as Peynado's to be noticed 
and marketed in a large forum. 

It has become patently clear that sus- 
tainable tourism is a viable and 
promising conservation tool. But it re- 
mains challenging to provide the res- 
idents of the world's most remote, 
fragile, and biodiverse ecosystems 
with the incentive to invest in the 
long-term vision of sustainable devel- 
opment — as opposed to the short- 
term gains of business as usual. Even 
if eco-establishments have the best in- 
tentions, it is by no means straightfor- 
ward to provide them with the tools, 
know-how, and capital to accomplish 
what they need to maintain a sustain- 
able ecosystem. 

Yet if Peynado's neighbors and his 
neighbors' neighbors come to realize 
the inherent wisdom of sustainable 
tourism — and more, convey that wis- 
dom to their guests — the benefits 
promised by sustainable development 
remain very much within reach. As 
Peynado puts it, "One of our main as- 
sets here is the environment. If that 
goes, your business goes. So if you can 
do anything to protect it, you know 
you'll still be in business." 

Carol Goodstein is the senior writer and 
editor for the Rainforest Alliance. She works to 
educate consumers on how their purchases can 
affect lives and lands of people around the world. 




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Art and Science 
Collide in the 
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Made possible with the generous support of 

Cosmic Collisions was created by the 
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CiT 



LIFE CYCLES 



The Other 
Kinsey Report 

Alfred C. Kinsey 's scientific interests went well beyond sex. 

By Peter Del Tredici 



ibJe Wild 



m'ca 



Alfred C. Kinsey, the sex doctor, 
died fifty years ago this August. 
The occasion offers the chance 
to reconsider a figure whose interests 
ranged over a great deal more than the 
varieties of human sexual behavior. 
Kinsey began his career as an ento- 
mologist, but he was also passionate 
about plants. In fact, he collaborated 
with Merritt L. Fernald, a prominent 
professor of botany at Harvard Uni- 
versity, to produce the classic Edible Wild 
Plants of Eastern North America. That 
book, published in 1943, still stands 
among the best of its kind for the num- 
ber of species it covers, the accuracy of 
its descriptions, and the practicality of 
its recommendations for harvesting and 
preparing wild foods. 

When I purchased my first copy of 
Edible Wild Plants in the early 1970s, at 
the start of my own botanical career, I 




Merritt Fernald, Kinsey's botanical 
collaborator, circa 1940 



had no idea that its author was the 
Alfred Kinsey of the famous Kinsey re- 
ports. Sexual Behavior in the Human Male 
(1948) and Sexual Behavior in the Hu- 
man Female (1953), each based on in- 
terviews with thousands of Americans, 
gained notoriety because they depict- 
ed a populace more sexually experi- 
enced and willing to experiment than 
the prevailing culture of the time cared 
to acknowledge. The two books 
sparked considerable controversy and 
public debate, made Kinsey a celebri- 
ty, established the field of sexology, and 
have been credited with launching the 
sexual revolution of the 1960s. But 
even after I belatedly made the con- 
nection between botanical manual and 
sexual expose, I never quite figured out 
how Kinsey, the famous sex doctor, and 
Fernald, the famous botanist — strange 
bedfellows if ever there were any — 
came to be linked through such a seem- 
ingly mundane subject as edible plants. 

My question lay dormant for near- 
ly thirty years, until I saw the bi- 
ographical movie Kinsey in December 
2004. In the opening scene, Professor 
Kinsey (played by Liam Neeson) is 
training his research assistants to record 
people's sex histories by having the as- 
sistants interview him. When an assis- 
tant asks about his education, Kinsey 
replies that he received his doctorate 
from "the Bussey Institution of Harvard 
University." The words made me sit 
straight up in my seat, as the proverbial 
light bulb turned on in my brain. The 



Edible Wild Plants of Eastern North America, 
shown above in its original, 1 943 edition, was 
the culmination of Alfred C. Kinsey's little- 
known passion for botany. 



Bussey Institution, now defunct, had 
been Harvard's agricultural college in 
Jamaica Plain, Massachusetts, adjacent 
to the Arnold Arboretum where I work. 
Fernald had been a professor there. 

Within a week of seeing Kinsey, I e- 
mailed the archivist at Harvard's Gray 
Herbarium to see whether there were 
any files on Kinsey related to Edible 
Wild Plants. The response came back 
positive: the archives held two folders 
of letters between Fernald and Kinsey, 
plus some manuscript pages for the 
book. I made an appointment to look 
over the files the following week, and 
I bought Jonathan Gathorne-Hardy's 
biography of Kinsey to find out what 
was already known about the history 
of Edible Wild Plants. Next to nothing, 
it turns out. That biography and oth- 
ers mention the book only in passing. 

Kinsey was born in Hoboken, New 
Jersey, on June 23, 1894. A sick- 
ly child, he had a tumultuous relation- 
ship with his father, who was sternly 
religious. Kinsey developed a deep love 
for the outdoors and found solace from 
his difficulties in the study of the nat- 
ural world. His interest in nature led 
him to join the Boy Scouts and, at age 
eighteen, he became one of the first 
Americans to attain the rank of Eagle 
Scout. He was particularly intrigued by 



22 



NATURAL Mis I OKY July/August 2006 




Kinsey examines galls — woody structures that gall wasps induce 
oak trees to produce — in this 1935 photograph. 



the varied art of wood- 
craft, the skill of living off 
the land, and spent most 
of his summers until age 
twenty-seven as a camp 
counselor in various 
parts of northern New 
England. 

In 1916 Kinsey grad- 
uated from Bowdoin 
College in Brunswick, 
Maine, with a degree in 
biology. That September 
he enrolled in the doc- 
toral program in eco- 
nomic entomology at the 
Bussey Institution. Fer- 
nald, a member of the 
Harvard faculty, taught a 
botany course at the 
Bussey. He had estab- 
lished his reputation by 
coauthoring the sev- 
enth edition of Asa 
Gray's famous Manual of Botany, pub- 
lished in 1908, and would later serve 
as director of the Gray Herbarium. It's 
not clear how Kinsey and Fernald met, 
but the Bussey was a small institution 
and the paths of the two men, who 
shared a common interest in plants, un- 
doubtedly crossed early in Kinsey 's 
tenure there. 

For his doctoral research, as movie 
fans will recall, Kinsey chose to work 
on gall wasps. The insects induce oak 
trees to produce bizarrely shaped 
woody growths to harbor developing 
gall-wasp eggs. By September 1919, 
doctorate in hand, he embarked on a 
year-long field trip to collect gall wasps. 
He traveled across much of the south- 
ern and western United States, on pub- 
He transportation and on foot, camp- 
ing and living off the land whenever 
possible. His travels ended by August 
1920, when he joined the zoology de- 
partment at Indiana University in 
Bloomington as an assistant professor of 
entomology. There, Kinsey continued 
working on gall wasps, collecting and 
classifying hundreds ot species and be- 
coming an authority on their evolu- 
tion, until he began his studies on hu- 
man sexuality in the late 1 930s. By that 



time, he had collected more than five 
million galls and gall wasps, now 
housed at the American Museum of 
Natural History in New York. 

Kinsey 's plan to write a book on ed- 
ible wild plants took root when he was 
still a student at the Bussey Somehow, 
while taking courses, working on his 
dissertation, and teaching undergrad- 
uate courses in zoology, he found time 
to compose a rough draft of Edible Wild 
Plants. In short, Kinsey's passion for 
botany was as strong as it was for gall 
wasps or, indeed, in later years, for sex. 
In any event, at some time before he 
graduated from Harvard, Kinsey en- 
listed Fernald as a coauthor of the 
book, undoubtedly to help flesh out its 
technical plant treatments. 

When I sat down at a long table in 
the library of the Gray Herbar- 
ium and began leafing through the 
sixty-four surviving manuscript pages 
of Edible Wild Plants, I was most struck 
by their physical appearance. Kinsey 
wrote the manuscript on a combination 
of now-crumbling newsprint and used 
sheets of herbarium card stock that had 
bits of old labels stuck to them. The 
pages are large — fourteen by twenty- 



two inches — and writ- 
ten on both sides in Kin- 
sey's distinctive, loopy 
hand [an enlarged example 
appears in the background 
on this and opposite pages]. 
A manuscript written on 
recycled paper is vintage 
Kinsey; even after he be- 
came famous for his sex 
research, he was notori- 
ous for his frugality. No 
doubt his interest in 
edible wild plants — read 
"free food" — was part of 
his belief in the intrinsic 
moral value of thriftiness. 

The surviving manu- 
script pages include an 
introduction, a classifi- 
cation of edible wild 
plants into fourteen cat- 
egories of uses, and de- 
scriptions of some thirty 
poisonous plants that could be mistak- 
en for edible ones. Remarkably, almost 
all of his writing has been preserved in- 
tact in the introduction and the first sev- 
enty pages of the published book. The 
classification into various usage cate- 
gories — including such idiosyncratic 
groupings as "Nibbles and Relishes," 
"Rennets," and "Masticatories and 
Chewing Gums" — is an early manifes- 
tation of Kinsey's lifelong fascination 
with taxonomy. All his research inter- 
ests reflect that urge to classify. Even 
more striking is the evidence of Kin- 
sey's attraction to primitivism, an incli- 
nation that shines through in the first 
two sentences of the book: 

'"Nearly every one has a certain amount of 
the pagan or gypsy in his nature and occa- 
sionally finds satisfaction in living for a time 
as a primitive man. Among the primitive 
instincts are the fondness for experiment- 
ing with unfamiliar foods, and the desire 
to be independent of the conventional 
sources of supply." 

The statement illuminates the philo- 
sophical basis of Kinsey's interest in 
wild plants. And its emphasis on ex- 
perimentation, primitive instinct, and 
independence from social norms seems 



July/August 200b NATUHAl HISTORY | 23 

I 



to foreshadow his interest in the nature 
ot human sexuality. 

Unfortunately, no manuscript pages 
survive for the great bulk of the book. 
The latter includes detailed descrip- 
tions and discussions of the edibility of 
more than a thousand species of plants, 
mushrooms, seaweeds, and lichens. It 
is thus impossible to determine pre- 
cisely who — Kinsey or Fernald — 
wrote which parts of the book. The 
handwritten manuscript pages make it 
crystal clear, however, that Kinsey de- 
veloped the book's format, established 
its tone, and wrote the first draft. Fer- 
nald added numerous species, brought 
the nomenclature and technical de- 
scriptions up to date, and commis- 
sioned the book's 149 illustrations. 

In reading through Kinsey and Fer- 
nald's correspondence, the earliest 
reference I found to Edible Wild Plants 
was in a note Kinsey wrote to Fernald 
on December 12, 1919, from Alam- 
ogordo, New Mexico, in the midst of 
Kinsey s cross-country gall-wasp-hunt- 
ing trip: "Hope the fate of the book is 
coming out all right." When he left 
Boston, Kinsey had apparently entrust- 
ed Fernald with the task of preparing 
the manuscript for publication. 

The next mention of the project 
comes about ten months later, on Oc- 
tober 5, 1920. In a letter to Fernald 
from his new home in Bloomington, 
Indiana, Kinsey inquired after the 
book and offered to resume work on 
it now that he had settled down. Fer- 
nald replied with the unfortunate news 
that the book had been rejected by a 
prospective publisher. Kinsey took the 
news philosophically, "I am, ot course, 
very sorry to hear that the publishers 
cannot handle the book at this time. I 
shall hope that a favorable opportuni- 
ty for getting the thing out will turn 
up before too long a time." 

In spite of their failure, though, the 
two men continued to exchange let- 
ters through 1926. In one of them, 
Kinsey suggested changing the manu- 
script entry for the American persim- 
mon: "Since coming into a region 
where the persimmon is abundant as a 



native, I have intended writing you 
that we must surely change our re- 
marks on this fruit. I am willing to go 
more miles to gather persimmons than 
any other wild food product that I 
know of." He concluded the letter 
with the following note: 

Every year since we have been married, 
Mrs. Kinsey has served persimmon pud- 
ding in our house two or three times every 
week from the first of September until De- 
cember. We venture to serve persimmon 
pudding whenever we have guests in the 
fall, and up to date have never found one 
who did not consider it a very great treat. 

A complimentary entry on the per- 
simmon and Clara B.M. Kinsey's 



recipe are included in the published 
book [see recipe above]. 

The correspondence between Kin- 
sey and Fernald slowed dramatically af- 
ter 1926. No mention of "the book" 
is made until January 7, 1943, when 
Fernald wrote excitedly to Kinsey: 

That long-buried manuscript on the Ed- 
ible Wild Plants has suddenly come to life. 
You may remember that 25 years ago I tried 
to get it published, but four different pub- 
lishers after accepting it, sent it back be- 
cause they saw no way to cover the ex- 
pense of the illustrations and thought that 
the market was too limited. Now it seems 
desirable to get the manuscript up-to-date, 
which I am doing, and the [dlewild Press 
of Cornwall, N.Y., has offered to print it 
in their best style (which is rather nifty). 

Kinsey responded positively to this 
"pleasant surprise," then went on to add: 



However, since my name is going to be on 
this thing, and since I have some scientif- 
ic reputation on the basis of my other work, 
I wonder if it would not be desirable to 
have me read the manuscript again before 
it goes into print. 

By "other work," Kinsey was refer- 
ring to his sex research, which he had 
begun m 1938 and was now thor- 
oughly absorbed in pursuing. Fernald 
had greatly expanded and embellished 
the manuscript, which now bore little 
resemblance to the original draft of 
1919. Yet Kinsey, ever the perfection- 
ist, went on to submit some five pages 
of detailed edits to the manuscript. 

It is probably no coincidence that Ed- 
ible Wild Plants, after lying dormant for 



so long, was published when it was. 
Kinsey had recently secured a grant 
from the National Research Council 
and the Rockefeller Foundation for his 
sex research. Ernest G. Stillman, an of- 
ficial at the book publisher, Idlewild 
Press, was also a graduate and benefac- 
tor of Harvard University, and a mem- 
ber of a prominent banking family. The 
well-connected Stillman would almost 
certainly have been aware of Kinsey's 
"other work" and its prominent hin- 
ders. And Stillman was surely mindful 
of the publicity value of having Kinsey's 
name on the book's cover, just when his 
sex research was gaining prominence. 

The book finally came oft the press- 
es in 1943. To the surprise of almost 
everyone involved, it was successful 
enough to warrant a second printing 
that same year. One reason was that the 



Clara B.M. Kinsey's Persimmon Pudding 



2 cups persimmon pulp 
1 cup (scant) sugar 

1 egg 

2 cups milk 
2 cups flour 



1 teaspoon soda 
1/2 teaspoon salt 
1 teaspoon cinnamon 
1/2 teaspoon cloves 
1/2 teaspoon allspice 



Combine the ingredients, beating well. It is best to 
save about half the milk until all the flour has been 
added. Pour about 1 1/2 inches deep in well greased 
pans and bake about an hour in a 325° oven. The 
pudding turns dark brown when it is done. Serve 
either warm or cold with whipped cream. Soft, juicy 
persimmons make the best pudding. 




NATURAL HISTORY July/August 2006 



U.S. Army, then in the throes of the 
Second World War, used the book in its 
wilderness-survival training program. 
The book's publication also coincided 
with food shortages then sweeping the 
nation. As Fernald pointed out in his 
revision of Kinsey's introduction, the 
consumer of edible wild plants "will be 
most content; and every time he will 
recognize that he has made small draft 
on the ration-book of coupons." 



I 



n 1947 Kinsey established the Insti- 
tute for Sex Research, Inc. (now the 
Kinsey Institute for Research in Sex, 
Gender, and Reproduction, Inc.) at In- 
diana University. The first of his ex- 
plosive reports was published in 1948, 
establishing his legacy. Fernald died in 
1950, shortly after finishing the eighth 
edition of Gray's Manual of Botany. Soon 
thereafter, Reed C. Rollins was ap- 
pointed director of Harvard's Gray 
Herbarium, and he wrote Kinsey to 
propose a revised edition ot Edible I Vild 
Plants. Kinsey agreed, but the publica- 
tion of the second edition, like that of 
the first, suffered long delays. In fact, 
Kinsey died on August 25, 1956, of 
congestive heart failure, before the sec- 
ond edition came out. Not until 1958 
did Harper & Row publish the second 
edition, which remained in print 
through the mid-1970s. Edible Wild 
Plants was reprinted in 1996 by Dover 
Publications, and it is once again wide- 
ly available at an affordable price. 

Who could have guessed that a man- 
uscript on edible plants, written on used 
herbarium sheets by a frugal graduate 
student in entomology, would become 
one of the classics in its field, entertain- 
ing and educating readers even eighty- 
seven years later? Its existence is testa- 
ment to an enduring collaboration by 
two authoritative scientists, and to Kin- 
sey's extraordinary intellectual flexibil- 
ity and scientific curiosity. Just don't leaf 
through it and expect to find any sex. 

Peter Del Tredici is senior research scien- 
tist at the Arnold Arboretum of Harvard I Uni- 
versity, where he has worked since 1979. He is 
also a lecturer at the Harvard Graduate School 
qf Design, where he teaches courses on plants, 
soils, and urban ecology. 



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William Sweet 



BIOMECHANICS 



Keep Me 
Hanging On 

Surviving in the intertidal zone 
tests the rubbery limits of algae. 

By Adam Summers ~ Illustrations by Tom Moore 



Now is a lovely time of year 
to head down to the beach. 
But forgo the warm sand 
in favor of the more interesting rocky 
headland down the shore. Then, as 
the waves pound in, consider what it 
must be like to live here. 

At low tide, the sun beats down 
and heats what little water remains in 
scattered pools, where oxygen levels 
madly fluctuate and salinity increases 
with each evaporative minute. When 
the tides change, the physiological 
insults ease, only to be replaced by 
the physical battering of the waves, 
which try alternately to shove things 
higher onto the shore and to suck 



them into the deep. The habitat 
might as well be called intertidal hell. 

Yet organisms from anemones 
to zooxanthellae are perfectly hap- 
py here. How surf-zone denizens 
manage to survive the wave-swept 
environment could fill entire books 
on biomechanics. But the story of 
one alga's fight to hang on caught 
my attention. 

Moving water exerts drag; no 
doubt you've felt it — the force 
that knocks you off your feet as you 
stand in the surf. It's the same force 
that scours rocks on the seashore 
clean of encrusting critters. In this 





context the drag on an organism 
changes with three factors: the speed 
of the water and the shape and the 
size of the organism itself. Faster 
water exerts a lot more force; in fact, 
drag varies directly with the square of 
velocity, so, for instance, doubling the 
water velocity bumps up drag four- 
fold. Size, or more properly cross- 
sectional area, also matters because 
the bulkier an object, the more rush- 
ing water slams into it. (A kayak 
pinned broadside to the current 
against a submerged rock is much 
harder to move than a kayak lodged 
against the rock head-on.) The way 
shape influences drag force is cap- 
tured by the drag coefficient, a term 
automakers invoke so often that you 
might think it applies only to cars. 

Creatures trying to make a living in 
the surf zone deal with the push and 
pull of waves by manipulating all 
three of these determinants of drag in 
their efforts to stay in the same gener- 
al spot. Many animals hide in crevices 
or in the lee of a rock, w T here flow 
speeds are lower. Others take an en- 
gineer's approach to the problem: 
they assume the minimum size that 
will enclose their feeding and repro- 
ductive organs — and never budge in 
size or position. Thus barnacles, 
limpets, and chitons that fall into the 
fixed-shape category are stuck with 
the same shape all the time. 

Other creatures, however, have 
opted for more flexibility. Two biol- 
ogists, Michael L. Boiler at Stanford 
University's Hopkins Marine Station 
in Pacific Grove and Emily Carring- 
ton at the University of Washington's 
Friday Harbor Labs on San Juan Is- 
land, are looking at how algae man- 
age to stay attached to their rocky 
homes despite battering waves. Algae 
can't take the fixed-shape path, at 
least not without sacrificing an awful 
lot of area needed for photosynthesis. 
They can't trot off to the far side of 
the rock, either, to hide from the in- 
coming waves. The solution, at least 
for some macroalgae, appears to in- 
volve tricky contortionism; they co- 
opt the force of the water to produce 





Irish moss responds to the speed of flowing water by changing its 
configuration, as seen from the side (top row) and from above (second row). In 
calm water it stands upright (left). Mild currents tug the alga into a cone- 
shaped position, which still allows for photosynthesis but minimizes drag 
(middle). In extreme conditions, the alga bends down and compacts even 
further into a streamlined form (right) that may prevent it from becoming 
detached or torn apart. 



changes in their own shape that si- 
multaneously reduce their area and 
their coefficient of drag. 

Boiler and Carrington worked 
with a common alga of New Eng- 
land and European surf zones, Irish 
moss (Chondrus crispus). Though 
called a red alga, Irish moss can range 
from dark purple to yellowish green, 
and it is shaped like a miniature tree 
about eight inches high [see illustra- 
tions above]. (It is also a source ot 
carrageenan, a thickener used in ice 
cream — and anything to do with ice 
cream is relevant to my kind of bio- 
mechanics.) They collected Irish 
moss samples of various size and 
shape, and glued their bases — appro- 
priately called holdfasts — to a plat- 
form that could measure drag force. 
Then they submerged the platform 
in a flume, the aquatic equivalent of 
a treadmill, and measured the drag 
force as they changed the flow speed 
from a gentle lapping to a punishing 
postgale surge. As the flow speed 
increased, the algae morphed into 
lower-drag shapes. 



In still water the algae stood tall 
and bushy with lots of area for the 
sun to stimulate the chloroplasts. In 
moving water the algae took two dif- 
ferent positions, depending on the 
strength of the flow. In languid wash- 
es, each stipe — an algal analog to the 
trunk ot a tree — bent over, so the al- 
gae's foliage brushed the bottom of 
the flume. The change decreased the 
area presented to the flow and re- 
shaped the algae from upright tree to 
pointed cone. At that stage, because 
drag forces were relatively low and 
the algae's canopies were still largely 
exposed, it's likely a good deal of 
photosynthesis could still take place. 

At faster flows, the algae morphed 
even more. As the flow speed rose, 
the canopies of the Irish moss became 
increasingly compact — each narrow- 
ing into a cone with an area less than 
half of its shape in still water. Further- 
more, the shape changes enabled the 
algae to hide their canopies in their 
own flow shadows and thereby slight- 
ly lower the drag coefficient. No 
question, the drag force on the algae 



increased with the speed of the flow, 
but not as fast as it would have with- 
out the change in shape. Above a cer- 
tain velocity, however, the algae reach 
a point where they cannot get any 
smaller. Carrington and Boiler aren't 
sure how much the final, squeezed 
shape affects photosynthesis; pro- 
longed exposure to fast water can't be 
good, but the organism can certainly 
weather the occasional storm. 

No amount of reconfiguration 
on the part of the Irish moss 
can keep up with a force change that 
depends on the square of water veloc- 
ity — the drag continues to increase 
with water speed until the current 
finally washes the algae away. But by 
allowing the stipe and canopy to go 
with the flow, the holdfast is usually 
saved from being ripped from the 
rock. It brings to mind blustery days 
I've spent at the rocky shore. Consid- 
ering my size, my area, and my high 
drag coefficient I would have done 
better positioning my posterior to the 
wind, and taken shelter in my own 
not inconsiderable bulk. 

Adam Si m.murs (asummers@uci.edu) is an 
assistant professor ofbioengineering ami of ecol- 
ogy and evolutionary biology ai the I University 
of California, Irvine. 



July/August 2006 NATURAL HISTORY 



27 



I WW- 



mm 

JULY/AUGUST 2006 



The Scaly Ones 

Squamata — lizards and snakes — have spread to almost 
every landmass and branched into more than 7,200 species. 
Ecological and molecular studies are bringing their family 
tree more clearly into focus. 



By Laurie J. Vitt and Eric R. Pianka 



They climb walls and scuttle upside 
down across ceilings, dive to the ocean 
floor to feed on algae, even glide 
through the air from treetops. Some, with no 
limbs and extremely long tails, look like snakes; 
others are snakes. Many are nearly invisible in 
their home habitats; others announce their pres- 
ence to their neighbors and warn off potential 
rivals by flashing colorful dewlaps, or fanlike 
structures, that lie just underneath their lower 
jaws [see photograph on page 32]. They dine on 
everything from microscopic insects to hefty 
animals. Some wield lethal toxins through long, 
hollow fangs. They are members of the order 
Squamata, "the scaly ones," more popularly 
known as lizards and snakes. They are also one 
of the most successful orders of tetrapod (four- 
legged) vertebrates on Earth. In some people 
they provoke a phobic reaction (particularly the 
snakes). But we, among many others, find them 
irresistibly fascinating. Then again, our interest is 
also a professional one: we have devoted our ca- 
reers to them. 

What particularly fascinates us is how, long 
ago, a common ancestor of squamates could 
have given rise to so many diverse descendants. 
Their living representatives — numbering more 
than 7,200 species — inhabit every continent ex- 
cept Antarctica and even many oceanic islands. 
When we look at them, we know that some of 
their similarities and differences reflect recent 
evolutionary adaptations, made in response to 
other species in their present-day environments. 
Other characteristics are a legacy of more an- 
cient adaptations in response to unknown con- 
ditions — early choices that set various groups 
on separate evolutionary trajectories. 

But with so many species and habitats, how 
can one reconstruct the group's evolutionary his- 
tory? Fossils tell only a limited story, and they are 
relatively rare. (Many of the ancestral species 
were small, and so their bones were less likely to 
be preserved — and more likely to be overlooked 
by paleontologists seeking bigger, more spectacu- 
lar finds.) Investigators have barely begun 
to probe the genetic data that might bring us 
closer to understanding the evolutionary rela- 
tions among living groups. But we think enough 
clues exist to sketch a coherent story. 

Our story begins when squamates and their 
nearest relatives, the Rhynchocephalia 
("beak-headed" reptiles, so named because their 
jaws have a beaklike tip) split from a common 



ancestor. According to Susan Evans, a paleontol- 
ogist at University College Loudon, the branch- 
ing probably took place sometime during the 
Lower or Middle Triassic periods, between 251 
million and 228 million years ago. At that time 
Earth's landmasses were united in one supercon- 
tinent, Pangaea. No one can be sure exactly 
when the split occurred, because the earliest 
known squamate fossils date only from Lower 
Jurassic sediments, between 200 million and 175 
million years ago, but those fossils suggest the 
group had already been evolving on its own for 
some time. Another reason paleontologists think 
squamates are older than their oldest known fos- 
sils is that earlier fossils have been discovered be- 
longing to their "sister" group, the rhyncho- 
cephalians. That group was widespread and 
diverse before the end of the Middle Triassic, but 
only two descendants have survived to the pre- 
sent: they are the two species of tuataras that 
occur in New Zealand. 

The common ancestor of squamates and rhyn- 
chocephalians was likely a small lizardlike reptile 
that ate insects and spiders. Although many skele- 
tal features distinguish squamates from their sis- 
ter group, one of the most important is found in 
the lower jaw. In the common ancestor, the lower 
jaw rotated from a pivot point on the bottom 
rear of the skull, which otherwise was relatively 
rigid. With the evolution of squamates, the skull 
bone that connected to the lower jaw — the 
quadrate — became only loosely attached by liga- 
ments to the rest of the skull. That new hingelike 
configuration, known as streptostyly, enabled the 
back of the jaw to move more freely [see illustra- 
tion on page 31]. In practice, it enabled the animal 
to deliver a faster and more powerful bite, and 
perhaps to open its mouth wider as well, making 
it much easier for ancestral squamates to capture 
and handle prey. 

Sometime between 30 million and 60 million 
years after the split between squamates and 
rhynchocephalians, the squamates themselves 
split into two major groups, Iguania and Scle- 
roglossa. Fossil evidence for the timing of that 
split is sparse, but it is consistent with the 
amount of divergence evident in the DNA of 
living species — a question investigated by J. 

An overfed, captive day gecko (Phelsuma madagascarien 
sis ) from Madagascar licks the transparent scale covering 
its eye. Lacking eyelids, the gecko cleans its eyes with its 
tongue. Another gecko parlor trick is walking upside 
down, thanks to many millions of microscopic filaments 
that make up the surface of its toe pads. 



July /August 2006 naickm HISTORY 29 



Robert Macey, a molecular biologist then at Wash- 
ington University in St. Louis, and his colleagues. 
Intrigumgly, the split appears to coincide with the 
breakup of Pangaea into two supercontinents, 
Laurasia and Gondwana. 

For some time, paleontologists reasonably theo- 
rized that that event, by separating two populations 
of squamates, initiated the evolutionary divergence 
of the two major groups. Investigators now know 
that early fossils of both groups were deposited in 
both zones of Pangaea before the land mass broke 
up. Nevertheless, that geological event apparently 
bore some relation to the evolutionary one. Most of 
the early diversification of iguanians took place on 
Gondwana, the southern continent, whereas most 
of the early diversification of scleroglossans took 
place on Laurasia, the northern continent. Why that 
is, however, remains unclear. 



w 



hen Iguania and Scleroglossa diverged, igua- 
nians retained most of the characteristics of 



their squamate ancestors. Iguanian skulls remained 
relatively rigid. They continued the early squamate 
lifestyle of lying in wait for prey and remaining 
cryptic — hidden or camouflaged — except when 
pursuing prey. And they continued to rely on vision 
to detect and discriminate prey and on what Kurt 
Schwenk, a functional anatomist at the University 
of Connecticut in Storrs, calls lingual prehension — 
literally, holding with their tongues — to capture and 
manipulate prey. Schwenk argues that lingual pre- 
hension was the ancestral mode of feeding in tetra- 
pod vertebrates, and so in squamates it may repre- 
sent the inheritance of a very ancient trait. 

The diversification of iguanians has been spec- 
tacular. Today they include most insect-eating 
lizards that tend to pursue their prey from fixed 
perches, such as chameleons; many other insectiv- 
orous species; and nearly all large plant-eating 
lizards around the globe — including iguanas, the 
group's namesake. Among iguanians is Moloch, the 
thorny devil of Australia [see photograph below], a 




Australian thorny devil (Moloch horridus), a lizard in the family Agamidae, specializes in eating 
ants, which it captures with its sticky tongue. Otherwise harmless, the lizard, shown here about 
life size, protects itself by sporting spiny scales, changing its coloration to match its background, 
walking slowly and jerkily (or freezing in place), and holding its tail erect (which may make the ani- 
mal look like a plant). When threatened, it puffs up and bends its head down between its legs, ex- 
posing the peculiar hump, or "false head, " on the back of its neck, instead of its real head. 



NATURAL HISTORY July/August 2006 



lizard that specializes in preying on ants and is 
so unusually shaped and well camouflaged 
that even experienced lizard biologists have 
difficulty spotting them. 

Of the insect-eaters, chameleons have 
adopted the most extreme form of the am- 
bush lifestyle. Chameleons have nearly elimi- 
nated pursuit; instead, they have a propulsive 
tongue that is often longer than their body 
[see photograph on pages 34-35]. A chameleon 
creeps within range of its insect prey, then 
hurls its tongue explosively at it. The prey 
sticks to the tongue, then gets rapidly pulled 
into the chameleon's mouth. All the while, 
the chameleon remains otherwise immobile, 
hidden by its cryptic shape and coloration. 
One of the main advantages of that strategy is 
that it reduces risk: when an animal moves, 
potential predators may see it. The strategy 
also saves energy: shooting forth the tongue 
"costs" less than chasing down prey. 

If there is a downside to the iguanian life- 
style, it is being tied down to real estate that 
matches the animal's camouflage. A lizard that 
looks like a leaf can be nearly invisible in a 
bush, but it stands out on a rock. So the need 
for camouflage has doubtless played an impor- 
tant role in the evolution of iguanian social be- 
havior. Most iguanians are territorial, fiercely 
defending areas where they blend in. There 
they remain unless another of their species 
usurps the favored place. 



Rigid skull 

Rhynchocephalian 
(tuatara) 




quadrate bone 



quadratojugal bone 




Streptostyly 

Squamate 
(chameleon) 





Mesokinesis 

Scleroglossan 
(gecko) 





Prokinesis 

Serpentes 
(puff adder) 





In sharp contrast to iguanians, scleroglossans 
evolved in ways that enabled them to cap- 
ture and manipulate prey with their jaws, an 
ability that Schwenk calls jaw prehension. 
That strategy freed up the tongue for tasks 
other than capturing prey, and the tongue be- 
came firmer as a result (scleroglossa means 
"hard-tongued"). Among the early adapta- 
tions in this group was the addition of a joint 
in the top center of the skull that enabled the 
upper jaw to bend upward and downward (try 
doing that with your upper jaw!). The flexible 
movement in the middle of the skull, known as 
mesokinesis, greatly increased biting efficiency by 
allowing the upper jaw to move downward as the 
lower jaw closes from the bottom up [see illustration 
on this page]. Snakes have a similar hinge, but it is in 
front of their eyes (a condition known as prokinesis). 
They also have additional flexible joints, such as one 
at the front of the muzzle that enables the left and 
right bones of the upper jaw and palate to move in- 
dependently (that is what makes it possible for a 



Joints of the skull and jaws (arrows) help distinguish members of the 
order Squamata (lizards and snakes) from one another and from 
members of the closely related order Rhynchocephalia. Skull of a tu- 
atara (a), a member of the order Rhynchocephalia, is relatively rigid. 
The lower jaw pivots from the lower end of the quadrate bone 
(green) and the adjacent quadratojugal bone. In skulls of squamates, 
including chameleons (b), the jaw pivots from the lower end of the 
quadrate. The upper end of the quadrate bone also enjoys some 
freedom of movement, a condition known as streptostyly, making it 
possible for the animal to move the rear of the lower jaw more 
freely in manipulating prey. Many squamates have an additional joint 
in the skull that enables the muzzle to flex upward and downward. 
In most lizards (c), that joint is behind the eyes (mesokinesis), but in 
snakes (d), it lies in front of the eyes (prokinesis). Snakes have other 
flexible skull and jaw joints; the viper (d), for instance, can also ro- 
tate its upper jaw bones that hold the fangs. 



snake to "walk" its head down over a large item of 
prey). Another important innovation in snakes is a 
loose, stretchable cartilaginous ligament that joins 
the front tips of the right and left lower jawbones: 
that allows the bones to move apart, enabling snakes 
to swallow exceedingly large prey (recall the draw - 
ing of a snake in The Little Prince). 

Switching from tongue to jaws for capturing prey 
might not seem groundbreaking. The change freed 
the tongue for other functions, however, and likely 



July/August 2006 NATURAL HISTORY 



31 



set the stage for the evolutionary enhancement of 
the vomeronasal organ, a chemosensory organ em- 
bedded in the roof of the mouth. That organ detects 
heavy, nonairborne molecules taken in through the 
mouth. It supplements nasal olfaction, which is the 
ability to smell airborne molecules that enter 
through the nostrils as the animal breathes. It is dis- 
tinct as well from taste, which is the ability to analyze 
chemicals with taste buds on the tongue. In scle- 
roglossans the enhancement ot both olfaction and 
vomerolfaction was lite-changing: not only could 
they rely less on sight to detect prey, but they could 
also perceive sex and sexual receptivity in their own 
species on the basis ot chemical cues alone. 

The avid way Gila monsters hunt out eggs suggests 
that enhanced chemical senses have helped some 
scleroglossans to find prey particularly rich in energy. 

But perhaps more im- 
portant, the enhanced 
sense of vomerolfac- 
tion also enabled scle- 
roglossans to identify 
dangerous prey — prey 
whose metabolic poi- 
sons or other defensive 
chemicals could be 
deadly or at least costly 
to digest. Several years 
ago we combined data 
we had gathered inde- 
pendently over our ca- 
reers and demonstrated 
that, compared with 
iguanians, scleroglos- 
sans eat many fewer 
ants, other hymen- 
opterans, and beetles, 
most of which produce 
noxious or toxic chem- 
icals. Most scleroglos- 
sans are highly active, 
and so they encounter 
numerous potential 
prey; that behavior 
may afford them the 
luxury of passing over 
noxious insects. 

As evolving chem- 
ical senses enabled 

Male fan-throated lizard from India (Sitana ponticeriana), pic- 
tured J.3X larger than life size, flashes its blue, black, and red 
dewlap to defend its territory from others of its species. The 
animal relies in large measure on camouflage for its own pro- 
tection as well as for ambushing insect prey, and so it must 
not cede suitable habitat to another lizard without a fight. 




scleroglossans to locate prey and potential mates 
without relying on vision, they adopted a more 
mobile searching strategy. This made them more 
conspicuous, requiring wariness, speed, and 
agility — not just camouflage — to escape predators. 
For the most part they ceased devoting time and 
energy to defending territories. Their chemical 
senses also enabled some scleroglossans to enter 
subterranean microhabitats and others to shift to 
nocturnal habits, both unavailable to iguanians that 
rely on vision as their primary sensory system. 

One possible measure of the success of the shift 
to jaw prehension and chemical senses is that 
in terms of extant species, scleroglossans outnum- 
ber iguanians 4.5 to 1. That ratio might overstate 
an advantage resulting mostly from chance. For ex- 
ample, scleroglossans could have split into separate 
groups a bit earlier than iguanians did in their evo- 
lutionary history, and the present-day diversity 
might simply magnify that small advantage. But 
scleroglossan success was real. A more convincing 
measure is that scleroglossan species outnumber 
iguanian species at nearly every site where both 
occur. In most places, scleroglossans dominate the 
ground, foraging freely over the landscape, whereas 
most iguanians are confined to rocks, shrubs, tree 
trunks, or other more restricted habitats. 

Subsequently — about 180 million years ago — 
scleroglossans split into two groups, Gekkota and 
Autarchoglossa, which differ in when they are ac- 
tive and how they use their tongues. Gekkotans in- 
clude, among others, geckos (after which the group 
is named) and the snakelike flap-foots of Australia. 
Most geckos are nocturnal. They have no eyelids; 
instead, the eye is covered by a "spectacle," or trans- 
parent scale, similar to the eye-covering of snakes. 
The tongue serves as a windshield wiper to clean 
the spectacles (as well as the Hps). Geckos also have 
a good sense of smell. William E. Cooper Jr., a bi- 
ologist at Indiana University— Purdue University in 
Fort Wayne, has shown that geckos detect airborne 
pheromones of other geckos, and discriminate prey 
on the basis of chemical signals. 

Geckos are also noted for being able to scale verti- 
cal surfaces and walk upside down on leaves, rock 
faces, and trees. They can even jump from tree to 
tree by catching a leaf on the second tree with a toe. 
Although some other lizards (anoles and a few 
skinks) can climb vertical surfaces with their toe 
pads, none are as adept as the geckos. Kellar Au- 
tumn, a biologist at Lewis & Clark College in Port- 
land, Oregon, has shown that gecko feet stick to sur- 
faces by van der Waals forces, a form of molecular 
attraction. Their toe pads have ridges, each ridge 



32 



NATURAL HISTORY July/August 2006 



covered with thousands of setae, 
hairlike structures that branch into 
hundreds of microscopic endings, 
called spatulae, that maximize con- 
tact with a surface. 

Flap-toots belong to the Aus- 
tralian family Pygopodidae. Py- 
gopodids are elongate lizards with 
no forelimbs and greatly reduced 
hind limbs. Some are burrowers, 
others terrestrial or arboreal. Many 
flap-foots swim through grass tus- 
socks. Some are nocturnal, others 
diurnal. Some mimic venomous 
snakes in coloration or by acting menacingly. 

One flap-foot, Lialis, acts more like a snake than it 
does other lizards in that it swallows very large prey, 
including other lizards. Skinks, Lialis's primary prey, 
are armored with bony plates known as osteoderms 
embedded in their scales, and so, like some skink- 
eating snakes, Lialis has evolved hinged teeth. When 




Flap-foot (Lialis burtonis), a snakelike, virtually limbless lizard shown here about 
two times life size, specializes in eating other lizards, which it swallows whole. It 
has an extremely flexible joint in the middle of the skull, which enables it to raise 
and lower its upper jaw when catching and killing prey. 



a tooth hits an osteoderm, it folds, whereas a tooth 
that goes between scales remains erect, giving it 
good purchase. As the skink squirms and wiggles in 
the jaws of Lialis, it literally ratchets itself down the 
predator's gullet. 

Autarchoglossans, "independent tongue" reptiles, 
pick up heavy, nonairborne chemicals from surfaces 



SQUAMATA 



RHYNCHOCEPHALIA 



SCLEROGLOSSA 



AUTARCHOGLOSSA 




Cladogram, a diagram that shows evolutionary branching points, depicts probable 
interrelations among living families and other large groups in the order Squamata, 
as well as their shared ancestry with the Rynchocephalia, once a much more wide- 
spread and diverse group. Within squamates, iguanians have prehensile tongues 
for capturing prey, an ancestral feature lost in scleroglossans. Autarchoglossans 
use their tongues to pick up heavy, nonairborne chemicals and deliver them to the 
vomeronasal organ, a sense organ in the roof of the mouth. 



July/August 2006 NATURAL HISTORY 



33 



with their tongues. The tongue then deposits the 
chemicals on the vomeronasal organ. Among the 
autarchoglossans are tegus and whiptail lizards, 
which march around in the hot sun in deserts and 
open tropical habitats of the New World, sticking 
their faces under surface objects to find insect larvae, 
digging into termite nests to feast on hundreds of 
termites, and even finding and eating carrion, all 
without relying primarily on vision. Other promi- 
nent members of the group are anguids, such as alli- 
gator lizards; Gila monsters; lacertids, such as jeweled 
lizards; monitor lizards; skinks; and all snakes. 

The long, thin tongues of monitor lizards and 
snakes take chemical sensing to its most sophis- 
ticated level. Not only can they discriminate chem- 
icals, but by comparing chemical dosages picked up 
on each fork of the tongue, they can detect edges as 
well as the direction of a chemical source. Just as 
chameleons are the logical endpoint to the evolu- 
tion of a sit-and-wait foraging strategy, snakes might 
be considered the logical endpoint within a group 
of organisms that have highly flexible skulls and a 
well-developed chemosensory system for locating 
and discriminating prey. 

And just as scleroglossans seem to have elbowed 
iguanians out of terrestrial habitats, so too autar- 
choglossans seem to have pushed gekkotans off the 
ground — or at least into a nocturnal lifestyle. Al- 
though one group of autarchoglossan lizards, the 
snakes, includes many nocturnal species (most from 
warm regions), autarchoglossans are generally ac- 
tive by day. In fact, their high activity levels usually 
require a high body temperature. Gekkotans oper- 
ate at lower body temperatures, but their nocturnal 
habits have limited their distribution to regions that 
are warm enough at night. Most geckos, for in- 
stance, live in the tropics or in deserts, and only a 
few live in colder climates. 

Autarchoglossans also continued another tradition 
ot their scleroglossan ancestors. Whereas chemical 
senses had enabled the scleroglossans to expand their 
ranges and relax their need to defend territory 
where they were camouflaged, the continuing evo- 
lution of those senses enabled the autarchoglossans 
to forage in places where they could not see. And in 
several families of autarchoglossan lizards, species 
evolved that dug burrows and lived underground. 

In many cases the subterranean lifestyle led to the 
evolutionary loss or reduction of limbs and to 
shortened tails. In some species, eyes were reduced 
to simple light-detecting organs — the animals had 
essentially shifted to a world dominated by chemi- 
cal signals. Other lineages evolved elongate bodies 
and tails, even as limbs were lost or reduced, u;iving 




rise to what are known in the United States as glass 
lizards (genus Ophisaurus). (The common term 
"glass lizard," however, can refer to species in sev- 
eral families of lizards that have evolved indepen- 
dently on different continents.) Neither limbless- 
ness nor subterranean activity has ever evolved in 
iguanian lizards. 

That brings us to snakes, which are characteristi- 
cally limbless. Although they figure large in 
people's lore and imagination, snakes are simply one 
evolutionary group (Serpentes) of scleroglossan 
lizards. They are closely related to lizards that belong 
to the family Varanidae, which comprises the Ko- 
modo dragon and other monitor lizards. They may 
have descended from a varanidlike ancestor, and a 
common assumption is that they evolved from some 
burrowing terrestrial lizard. Another theory, how- 
ever, is that the first snakes were aquatic, having 
evolved from the mosasaurs, an extinct group of 
large marine reptiles that were also closely related to 
the varanids [see "Terrible Lizards of the Sea," by 
Richard Ellis, September 2003]. But even if terrestrial 
snakes descended from an aquatic ancestor, herpetol- 
ogists generally agree that today's species ot aquatic 



34 



natural HISTORY July/August 2006 




Veiled chameleon (Chamaeleo calyptratus), like other chameleons, captures insects at great 
distances with its tongue, which in this individual extends about ten inches. Chameleons are 
iguanians, most of which manipulate prey with the tongue, though a few are vegetarians. 
Members of the other major group of squamates, the scleroglossans, capture prey with their jaws. 



snakes have all descended from terrestrial snakes. 

What a snake can find is limited only by the size 
of crevice or hole that it can stick its head into; 
what a snake can eat is limited in size only by how 
tar it can disarticulate one of the most flexible skulls 
known in vertebrates. As a result, snakes have be- 
come top predators, coming back to haunt such 
close evolutionary relatives as the lizard autar- 
choglossans as well as iguanians and gekkotans. 
Many snakes produce venoms, with which they kill 
large prey and retaliate against would-be predators. 
So do some lizards, such as the Gila monsters [see 
Venomous Lizards of the Desert," by Daniel D. Beck, 
July/August 2004]. Some snakes (including pit 
vipers, many boa constrictors, and some pythons) 
have heat-sensing pits in one or more scales along 
the jaw, wired directly into the optic neural system, 
which essentially enable them to see in the dark by 
detecting changes in the thermal landscape. 

Many venomous snakes have brightly colored 
rings (as do Gila monsters) that warn potential 



predators that they are dangerous. A host of non- 
venomous snakes have evolved color patterns that 
mimic those of venomous species, thereby taking 
advantage of the protection a venomous reputation 
affords against potential predators. People are 
among the many large animals that instinctively 
give snakes a wide berth. The threat of a ven- 
omous snake, not to mention the dangers posed by 
large constrictors, probably ingrained that instinct 
in our early mammalian ancestors. 

Whether we are attracted or repelled by snakes 
and other squamates, we owe the group respect for 
its evolutionary success. Along with turtles and croc- 
odilians, they are the reptiles that we see around us 
today. Dinosaurs, ichthyosaurs, plesiosaurs, and 
pterosaurs were impressive in their time, but all (ex- 
cept for birds) were long gone before humans came 
along, as much as we might fantasize about "lost 
worlds." Squamates, on the other hand, watched the 
dinosaurs come and go. Chances are they will be 
around to watch humans exit as well. 



July/August 2006 NATURAL H1STOU.Y 



35 



From Fins to Limbs 



Recent fossil discoveries show how four-legged land animals 
evolved from fishes whose filllike paddles had already adapted 
to functions such as pushing through shallows and swamps. 

By Jennifer A. Clack 



When I became a paleontologist about 
twenty-five years ago, the evolution of 
four-legged animals from their fish an- 
cestors was embodied in khthyostcga, a partly terres- 
trial creature that lived 36< I million years ago in what 
is now East Greenland. Ichthyostega was the oldest 
known tetrapod — an animal having four legs with 
toes. On the other side of the evolutionary divide 
was Eusthenopteron, a fish that was about ten million 
years older than Ichthyostega. In Eusthenopteron pale- 
ontologists saw the model ancestor to the tetrapods: 
the skeleton of its fin seemed the archetype from 
which all limbs evolved, including our own. 

Those two iconic animals stimulated speculation 
about how creatures crawled out of the water to 
"conquer the land." According to the simplest sce- 



nario of the day. a fish such as Eusthenopteron left one 
drying-up pool to find another and thus grew legs. 
But Eusthenopteron and Ichthyostega were only two 
widely separated points of reference; the interme- 
diate steps were missing. And little could be said 
about what encouraged animals onto land, how the 
transition happened, or when it took place. 

Ichthyostega had first come to light in the early 1 930s. 
In 1897 a party of explorers known as the Andree ex- 
pedition, traveling by balloon, had been lost attempt- 
ing to find the Northwest Passage — the fabled navi- 
gational shortcut across the top of the world. Decades 
later. Scandinavian scientists were searching for the 
remnants of that expedition in East Greenland, when 
they found a cache of Ichthyostega fossils, among oth- 
er eeoloeical discoveries. After that. Greenland be- 




36 NATURAL HISTORY July. 'August 2006 




came a magnet for competing Scandinavian geolo- 
gists, with Ichthyostega as one of the prizes. 

At the time of Ichthyostega's discovery, another crea- 
ture from East Greenland, called Acanthostega, was 
known; it had been identified in the 1940s as a sec- 
ond kind of early tetrapod, on the basis of two in- 
complete skulls. Those tantalizing skull fragments 
were from the same time (and, evidently, the same 
place) as the fossils of Ichthyostega: from the Late De- 
vonian, about 365 million years ago. Because of the 
movements of continents driven by plate tectonics, 
Greenland has not always been an Arctic island; in 
the Late Devonian, it was part of a huge landmass 
at the equator and was rich with the life-forms of 
the period [see map on next page] . Hence Greenland 
beckoned to paleontologists as the probable site of 
one of the great events in the history of life on earth. 

In the summer of 1987 I was fortunate to get the 
chance to explore several places in central East Green- 
land where more Devonian tetrapods were likely to 
be found. Mounting a Greenland expedition was a 
daunting prospect for a novice like me. It required 
ample stores of food, a radio-support network, heli- 



copters to get in and out of the region, and firearms 
to ward off polar bears and musk oxen. As luck would 
have it, a team of Danish scientists from the Green- 
land Geological Survey was completing a three-year 
project in the same area my colleagues and I wanted 
to explore and had all the logistical resources in place 
to serve our expedition. Thanks to their good offices, 
the expedition was blessed with success. 

We pinpointed a prime site 2,600 feet up a steep 
mountainside. During our first days in the field, the 
climb to the site took us most of a day, but by the 
end of four weeks, we could scramble up in just 
two and a half hours. With twenty-four hours of 
daylight, we could spend a long spell on the moun- 
tain. The fossils we discovered were well worth the 
effort; on returning from the field, we had enough 
of them to recreate the anatomy of Acanthostega and 
its mode of locomotion. And in the same general 
location, though in slightly different sediment beds, 
we found a few remains of Ichthyostega. The story 
of the transition from water to land began to gath- 
er momentum. 

The Greenland fossils and subsequent discoveries 



Aquatic tetrapods, or four-legged swimmers, evolved during the Devonian period (between 
416 million and 359 million years ago) to become the first four-legged land animals, as fins were 
transformed into limbs with fingers and toes. The four animals shown below (not to scale) are 
(left to right): Eusthenopteron, Tiktaalik, Acanthostega, and Ichthyostega. Limbs might have 
given an advantage to transitional forms such as Tiktaalik in navigating swampy waters or in 
pushing across the bottoms of riverbeds; eventually, the limbs of some tetrapods became able 
to bear weight on land. The insets show the creatures' right forelimbs (except for Ichthyostega, 
which is a right hind limb); the scale bars each represent one inch. 




Ichthyostega and Acanthostega 
Kejser Franz Joseph Fjord, Greenland 



Tiktaalik 
Ellesmere 
Canada 



Elginerpeton 
Scat Craig, 
Scotland 



Elpistostege and 
Eusthenopteron 
Miguasha, Quebec 



Hynerpeton and 
Densignathus 
Hyner (Red Hi 
Pennsylvania 




eton and Jakubsonia 
id Livny, Russia 



Ventastega 
Pavari, Latvia 



Livoniana 
Ligatne, Latvia 



hthyostegid 



Continents and oceans of the Late Devonian epoch (between 385 million 
and 359 million years ago) were situated as shown on the map. The regions 
that later became modern-day countries and continents are also outlined. In 
general, landmasses in the Late Devonian were farther south and more con- 
centrated around the equator than they are today. Tetrapods and their clos- 
est relatives have been discovered at the sites indicated by colored dots, 
and also occur in China and Australia (not shown). 



have forced paleontologists to rethink virtually every 
piece of "settled" knowledge about the origin of 
four-legged animals. Not only is there a new un- 
derstanding of the anatomical innovations embod- 
ied by Ichthyostega and Acanthostega. But more, pale- 
ontologists have assembled a picture of the global 
distribution of Devonian tetrapods, as well as the ex- 
tent of their diversity, that was unthinkable even a 
decade ago. One of the most exciting new fossils is 
Tiktaalik, a fish-tetrapod "missing link" whose dis- 
covery in the Canadian Arctic by paleontologists 
from the National Academy of Natural Science in 
Philadelphia and from the University of Chicago 
made front-page news this past April. Although no 
single fossil can fully explain a complex evolution- 
ary event, Tiktaalik is a true intermediate form, and 
it provides vital clues to the when, where, and how 
of the transition from water to land. 



B 



ack in my laboratory at the University Museum 
of" Zoology in Cambridge, England, we exam- 
ined our haul of Acanthostega fossils. Acanthostega 
turned out to be not terrestrial, but aquatic. It had 
short ribs, uniformly shaped vertebrae, and a tail with 



an oar-shaped fin supported by 
bony fin rays. It also breathed 
with its gills, like a fish. Acantho- 
stega's two-foot-long body 
could readily bend from side to 
side as it propelled itself through 
the water with lateral move- 
ments of its tail. 

One big surprise was that 
Acanthostega had not five digits 
on each of its four limbs, but 
eight. So there was no original 
template for rive fingers or toes. 
The story that land animals 
evolved when fishes such as Eu- 
sthenopteron emerged from the 
water to crawl over land and lat- 
er developed limbs wasjust that: 
a story. Instead, we suggested, 
limbs may have evolved first as 
paddles, which were used to 
swim, to spread the animal's 
weight across a soft, muddy 
riverbed, or to push through 
the swampy, weed-choked wa- 
ters of streams and lake margins. 
Only later did each limb lose a 
few toes, become able to bear 
weight, and turn into a leg for 
walking on land. 

Ichthyostega, too, had a tale to 
tell. The first specimens of Ichthyostega to emerge 
from Greenland were found by Danes but were stud- 
ied mainly by Swedes. Erik Jarvik, one of the most 
influential of the Swedish paleontologists in the mid- 
twentieth century, published a reconstruction of 
Ichthyostega that remained the basis of popular and 
scientific conceptions of early tetrapods for decades. 
His version of Ichthyostega was a three-foot-long 
quadruped with a complement of specialized fea- 
tures, including broad, overlapping ribs and a per- 
manently bent elbow, which seemed at odds with 
Ichthyostega's role as a very early tetrapod. The tail, 
though, was finned like that of a fish and marked 
Ichthyostega as primitive. 

The specimens from our 1 987 expedition gave 
us the first clue that something was wrong with 
the earlier image of Ichthyostega. Once back in the 
lab, my colleagues and I prepared the Ichthyostega 
bones by removing their surrounding rock with 
tools such as a dental mallet and a handled needle, 
all under a high-power binocular microscope. We 
found that instead of five toes, or eight, Ichthyostega 
had seven: three tiny ones bunched together at the 



38 



NATURAL HISTORY July/August 200b 



leading edge of die foot, trailed by four stout ones. 
Instead of a weight-bearing foot with five toes, as 
pictured by Jarvik, we found that the entire hind leg 
was shaped like a paddle [see photograph on page 41]. 
An analogous appendage, which evolved indepen- 
dently (and with five toes, not seven), is the fore- 
limb of the modern river dolphin. 

That discovery alerted us to other problematic as- 
pects of Ichthyostega's anatomy, as it had originally been 
conceived. To make accurate estimates of the relative 
sizes ofbody parts, paleontologists ideally need a head, 
a trunk, a forelimb, and a foot from the same indi- 
vidual. We lacked such a complete package; our best 
evidence showed that instead of having hind limbs 
larger than forelimbs, as in most tetrapods, Ichthyoste- 
ga had big, strong forelimbs paired with diminutive 
hind limbs. Was that real- 
ly the case, or was this con- 
clusion merely an artifact 
of examining a composite 
skeleton? 

To investigate further 
the apparent anomaly of 
leg size, I organized a sec- 
ond expedition to Green- 
land in 1998, aiming to 
find more Iclithyostega 
material. Quite by chance, 
all four of our team mem- 
bers were female, so we 
called ourselves the Girls 
in Greenland expedition. 
Again, we were fortunate 
in having the resources of 
the Danish geologists to 
help us. As so often hap- 
pens in collecting expedi- 
tions, we discovered our 
best material in the last few 

days of the five-week field season, but it proved cru- 
cial. We collected shoulder, forelimb, trunk, and hind- 
limb bones, all from the same individual animal, which 
gave us the correct proportions for the limbs. 

We also found a well-preserved skull from a dif- 
ferent individual. Gompared with the rest of the 
skeleton, skulls are complex and full of information. 
They not only enable paleontologists to determine 
relations among groups of animals, but in the case 
of early tetrapods, they also reflect changes that were 
as vital to life on land as limbs were. For example, 
Iclithyostega skulls indicated how breathing organs 
and ear regions derived from the gill areas of fish. 

Drawing together our fresh material and the pre- 
viously collected specimens in the Cambridge lab, 
we examined all our fossils with newer mechanical 



techniques and also with the newly developed proc- 
ess of CT scanning, specially geared to see through 
rock. We gave Iclithyostega a complete makeover. 
With most tetrapods, including Acatithostega, we 
could be reasonably sure which parts — ears, for in- 
stance — corresponded from one animal to anoth- 
er. But Iclithyostega was so weird in the regions at 
the back of the head, where the ears and brain had 
been, that interpreting their evolution had never 
been possible before. CT imaging and modeling 
helped us understand the anatomy of that area. We 
were able to conclude that the animal had a high- 
ly specialized ear that was probably adapted for use 
in water. For example, it might have enabled 
Iclithyostega to listen for aquatic prey. Alternatively — 
if we infer that Iclithyostega was itself able to pro- 




inches 



Recent skeletal reconstruction of Ichthyostega (top) shows the unusual shape 
of the back, the paddlelike hind limbs, and the broad overlapping ribs. No 
"hands" of the creature have been found, but the "arms" and shoulders 
were strong and could hold up the front part of the body. A skeletal recon- 
struction of its contemporary, the more aquatic Acanthostega (above), shows 
a body better adapted for swimming. All four limbs were paddlelike, and the 
tail fin was deeper and longer than it was in Ichthyostega. 



duce sound to communicate — the ear might have 
helped individuals hear one another and perhaps 
find mates. 

The next part of Ichthyostega we reconsidered was 
the vertebral column, or backbone. Earlier re- 
constructions had shown it as made up of elements 
that were more or less uniform along the entire length 
of the backbone, as is the case in Acanthostega. The 
neural spines (equivalent to the bumps you can feel 
when you run your finger up the middle of your back) 
were all shown pointing backward and all roughly the 
same length. Instead, we noticed that the neural spines 
changed their direction progressively from the shoul- 
der to the hip [see upper illustration above]. In the cen- 
tral, thoracic region the spines pointed conventional- 



July/August 2006 NATURA1 HISTORY 



3^ 



ly backward, but then, in the lumbar region, each suc- 
ceeding one tilted a bit farther forward and was taller 
and broader than the one in front. Even farther back 
they began to change again, tilting backward but with 
a forward curve at the top. The vertebral column could 
thus be divided into regions, which suggests that those 
regions, and the muscles attached to them, were spe- 
cialized for distinct jobs. Just how it all worked is not 
yet clear, but any spinal and muscular division of la- 
bor is extraordinary in such an early tetrapod. It oc- 
curs today only in mammals. 




Skull of Acanthostega is shown about three-quarters actual size. The 
creature had the gills of a fish and the fingers and toes of a tetrapod. 



How did Ichthyostega move? The most recent ev- 
idence told us that it moved like nothing we had 
imagined. Ichthyostcga\ body plan would have re- 
stricted sideways bending — the lateral moves one as- 
sociates with, say, Acanthostega, or a modern sala- 
mander. But Ichthyostega could have readily flexed its 
body up and down. It turned out that our first guess- 
es about the hind limbs were wrong — they were not 
very small after all. One possibility is that Ichthyostega 
moved its forelimbs forward in tandem for a power 
stroke and thus inchwormed along, a gait more com- 
mon in modern mammals than in modern reptiles. 
Think of a seal using its two forelimbs to haul itself 
out of the water and clamber onto a beach. 



Although Iclithyostega and Acanthostega were con- 
temporaries in the same geographic area, they 
lived in contrasting environments. Acanthostega was 
mostly aquatic; Ichthyostega was partly terrestrial. In 
locomotion and lifestyle, too, Ichthyostega was as dif- 
ferent from Acanthostega as chalk is from cheese; pret- 
ty much all they have in common is four legs and 
the endings of their names. But beyond those two 
examples, the understanding of other tetrapods, 
their diversity, and the environments that hosted 
them is exploding. The 1987 Acanthostega fossils had 
unexpectedly revealed distinctive features of the 
teeth and jaws, features that became the key for rec- 



ognizing the difference between the jaws of early 
tetrapods and those of the contemporary fish. We 
reexamined caches of previously indeterminate or 
largely ignored fossil fragments in museum collec- 
tions. Sure enough, a series of bone fragments from 
Scotland, even older than the ones from Greenland, 
proved to be from Devonian tetrapods. 

The pace of discovery picked up with further ex- 
amples from Belgium, China, Latvia, Russia, and the 
United States. Trackways have now confirmed the 
presence of early tetrapods in Ireland and even in Aus- 
tralia. Fresh field collecting is 
proceeding in several of those 
regions, with an eye toward 
finding tetrapods. 

In short, Devonian tetra- 
pods have gone global. Nine 
species have been named, and 
more are in the pipeline. With 
the possible exception of the 
specimen from Belgium 
(which may be a close relative 
of Ichthyostega), each tetrapod 
is distinct and unique to its 
own geographic area. Some of 
the bones are mere frag- 
ments — strangely, mostly 
jaws — but the more complete specimens are showing 
how creatures adapted anatomically to their habitats. 

But what about that first step? Which creature 
was the first to venture out of the water, and how, 
when, where, and in what circumstances was that 
move accomplished? Pinning down the order in 
which fish gained the necessary anatomical equip- 
ment would go a long way toward explaining the 
transition. One of the most important recent dis- 
coveries helping to answer some of the questions is 
not a tetrapod. It is, however, as close a relative to 
a tetrapod as it could be while still being fishlike. In 
2005 Neil Shubin of the University of Chicago and 
his team discovered spectacular fossils of a "near 
tetrapod" on Ellesmere Island in Nunavut Territory, 
Canada. They named it Tiktaalik. 



T 



iktaalik lived between 385 and 383 million 
years ago and is one of three kinds of near 
tetrapods known from the early part of the Late De- 
vonian. Each one lived in what were then estuaries 
and river channels around the coasts of the old con- 
tinent of Laurussia, which straddled the equator and 
encompassed parts of what are now North Ameri- 
ca and northern and eastern Europe. Their presence 
suggests that tetrapods originated in that region, 
perhaps just a short time later, geologically speak- 
ing. The earliest evidence of limbs comes from de- 



40 



NATURAL HISTORY July/August 2006 



posits in Scotland that are around 376 million years 
old. Taken together, the evidence seems to peg the 
origin of tetrapods neatly to a period of less than 
ten million years in the Late Devonian, and to a rec- 
ognizable geographical area. 

Because of its nearly complete preservation, Tik- 
taalik has also answered major questions about the 
order in which tetrapodlike physical features arose, 
and perhaps even what they evolved to do. Changes 
to the head came first, in response to a greater re- 
liance on air breathing. Tiktaalik had lost a series of 
bones that join the head to the shoulder in fishes and 
that protect and help operate the gill-breathing sys- 
tem. Thus, Tiktaalik haci a neck — an outstanding 
tetrapod feature. The neck gave the head a greater 
range of movement, enabling the animal to raise its 
head out of the water to gulp air. Compared to 
Eusthenopteron and similar fish, the pocket in which 
air was exchanged or stored had become enlarged, 
and some of the gill apparatus was already evolving 
toward the configuration that tetrapods eventually 
used for hearing. 

Crucially, though, the forelimbs of Tiktaalik com- 
bine traits of fishes and tetrapods. Although its fins 
still had fin rays and webbing, they were much short- 
er than those of its nearest fish relatives. The skele- 
tons of the fins were robust and flexible in much the 
same ways as tetrapod limbs. The fins could have 
served as props for the body — Tiktaalik 
had enlarged ribs that served as a kind £gQ§ 
of scaffold for trunk musculature that 
stiffened the body — as well as a rudi- 
mentary means of walking. The fin 
bones, however, were still more 
similar to the fin bones of closely 
related fishes than to the digits that 
eventually evolved in the ear- 
liest tetrapods. Tiktaalik helps 
confirm that key anatomi- 
cal changes took place while 
the animals were still techni- 
cally fish, and that develop- 
ments to the limbs began 
with modifications in func- 
tion, before the main changes 
in form evolved. 



The next step for us is to 
go beyond the bones. If 
we could look at sediments 
in which tetrapods were pre- 
served along with other con- 
temporary plants and ani- 
mals, we could put tetrapods 
in their ecological context. 



Right hind limb of Ichthyostega, measuring six 
inches long, could not have borne its share of 
the animal's weight. It is paddlelike and shows 
no real knee or ankle joint. The triangular bone 
at the top of the fossil is the pelvis. 



A chance to do just that emerged in a Pennsylvania 
site known as Red Hill. It has yielded several frag- 
ments belonging to at least three distinct tetrapod 
species. The surrounding sediments showed that the 
climate was warm and subtropical, yet seasonally 
variable. The Red Hill tetrapods lived in a river basin 
surrounded by diverse flora and fauna. 

About 385 million years ago, or a little less, dense 
forests were beginning to grow beside rivers and lakes. 
The onset of a seasonal climate in the Late Devon- 
ian had promoted the evolution of deciduous trees. 
As they dropped their leaves into the water, bacteria 
that feasted on their remains used up most of the oxy- 
gen in the water. At the same time, oxygen levels in 
the atmosphere were beginning to rise, and so any 
creature that was more effective than other animals 
at breathing air would have had an advantage. 

Invertebrates such as millipedes, mites, scorpions, 
and primitive wingless insects had crawled onto land 
and filled an array of damp, green habitats. They had 
also gotten bigger and become potential sources of 
food for four-footed predators. Once true limbs 
evolved, tetrapods were better able to exploit areas 
of densely vegetated shallow water and swamp that 
fish with fins could not. 

In the past twenty years, discoveries have radical- 
ly changed what we paleontologists think about the 
origin of four-legged animals. Important finds have 
altered what we thought we 
knew about the gradual 
transition from water to 
land, as some pieces of the 
puzzle have been moved 
about and others added. 
With Tiktaalik, an inter- 
mediate stage between 
finned Eusthenopteron and 
footed Ichthyostega has come 
into focus. Acanthostega and 
Ichthyostega have revealed 
their bone structures, modes 
of moving, and lifestyles. The 
Red Hill fossils have provided 
an ecological context. More ex- 
ploration will only make the story 
richer. The same holds for the knowl- 
edge of how tetrapods diversified and 
spread out. The early ones traveled quick- 
ly on their four feet. From one point of ori- 
gin, they soon fanned out into 
far-flung parts of the Late De- 
vonian world and adaptivelv 
made themselves at home — on 
on feet. The rest is evolu- 




i.inii 



tionarv history. 



□ 



July/August 2006 NATURAL H1STOK.Y 



41 



Beyond the Big Banj 

A new cosmic worldview holds that countless replicas of Earth, 
inhabited by our clones, are scattered throughout the cosmos. 



By Alex Vilenkin 

We all live in the aftermath of a great ex- 
plosion. This awesome event, some- 
what frivolously called the big bang, 
took place some 14 billion years ago. We can actu- 
ally see some of the cosmic history unfolding be- 
fore us since that moment — light from remote 
galaxies takes billions of years to reach our tele- 
scopes on earth, so we can see galaxies as they were 
in their youth. But there is a limit to how far we 
can see into space. Our horizon is set by the maxi- 
mum distance light could have traveled since the 
big bang. Sources more distant than that horizon 
cannot be observed, simply because their light has 
not yet had time to reach Earth. 

But if there are parts of the universe we cannot 
detect, who can resist wondering what they look 
like? Do they simply harbor more stars, more 
galaxies, more of the same — or could it be that dis- 
tant parts of the universe differ dramatically from 
our cosmic neighborhood? Does the universe ex- 
tend to infinity, or does it close in on itself, like the 
surface of the Earth? 

As they address these provocative yet fundamental 
questions, cosmologists can rely only on indirect, 



circumstantial evidence, using measurements made 
in the accessible part of the universe to make infer- 
ences about the places that cannot be observed. 
That limitation makes it much harder to prove one's 
case "beyond a reasonable doubt." But because of 
remarkable recent developments in cosmology, 
some of the ultimate cosmic questions now have an- 
swers that we have some reason to believe. 

The emerging cosmic worldview combines, in 
surprising ways, some seemingly contradictory 
features: the universe is both infinite and finite, 
evolving and stationary. That view of the universe 
also holds that in some remote regions there are 
planets exactly like our Earth, with continents of 
the same outline and terrain, inhabited by identical 
creatures, some of them holding copies of this 
magazine in their hands. 

The core of the new cosmological paradigm is 
"eternal inflation," a subject of my research that 
grew out of the theory of inflation first put forward 
m 1980 by Alan Guth, a physicist at the Massachu- 
setts Institute of Technology. Guth suggested that the 
early universe contained some highly unusual mate- 



4? 



NATURAL HISTORY July/August 2006 



Dennis Oppenheim, Image Dissonance — Coffee Cup, 1988-89 



rial that created a strong repulsive gravitational force. 
That special material is known as the false vacuum, 
and according to Guth, it blew the universe up. 

A vacuum is empty space — space devoid of all 
material particles. It is often regarded as synony- 
mous with nothing. But according to modern the- 
ories of elementary particles, a vacuum is a physi- 
cal object; it can be charged with energy and can 
come in different states. We live in the lowest- 
energy vacuum, the so-called true vacuum (famil- 
iar empty space). High-energy vacuums are called 
false because, unlike the true vacuum, they are un- 
stable. The most remarkable property of a false 
vacuum is its repulsive gravity. According to Ein- 
stein, if a vacuum has energy, it should also have 
tension, which has a repulsive gravitational effect. 
The repulsion due to vacuum tension turns out to 
be three times stronger than the attractive gravity 
of the vacuum energy (which is related to mass via 
Einstein's formula E=mc 2 ). The net effect is a 
strong repulsive force. 

Guth considered what would happen if, at some 
early epoch, the entire universe were in a false-vac- 
uum state. He found that the repulsive gravity of the 
vacuum would cause the universe to expand expo- 
nentially — or, in other words, by a constant factor 
for each constant interval of time. Exponential 
growth can be characterized by the doubling time, 
or the time it takes for a given quantity to double in 
size. (The doubling time for $100 invested at 6 per- 
cent annual interest, for instance, is about twelve 
years, so that at the end of twenty-four years the 
$100 investment is worth about $400.) 

For the expansion of a universe permeated by a 
false vacuum, the doubling time is unbelievably 



short. It depends on the energy density (measured 
in units of energy per cubic centimeter) of the par- 
ticular kind of false vacuum, but it never exceeds 
one ten-billionth of a second. A straightforward 
calculation shows that the universe would expand 
by a factor of a googol (10'"") in less than one-thir- 
tieth of a microsecond. 

Since a false vacuum is unstable, it eventually de- 
cays, turning into the true vacuum. In so doing, its 
prodigious energy ignites a hot fireball of elemen- 
tary particles. That event signals the end of inflation 
and the starting point of the usual cosmological 
evolution. It plays the role of the big bang in Guth's 
cosmology. Thus an enormous, hot, expanding 
universe emerges from a tiny initial seed. 

The theory of inflation was little more than a 
speculative hypothesis when Guth proposed 
it, but it was soon enhanced and developed by 
the work of many physicists, most notably An- 
drei Linde of Stanford University. Moreover, in 
the late 1990s, observations of distant supernovae 
and of the cosmic microwave background radia- 
tion — a faint afterglow of the big bang — gave the 
theory an enormous boost of corroborating ob- 
servational evidence. So today inflation is well 
on its way to becoming one of the cornerstones 
of modern cosmologv. 

In a way, inflation caused by a false vacuum is 
similar to the reproduction of bacteria. In both 
cases, two processes compete for dominance: bac- 
teria reproduce by division, but occasionally they 
are also destroyed by antibodies. The outcome de- 
pends on which process is more efficient. It the 
bacteria reproduce faster than they arc destroyed, 



July/August 2006 NATURAL HISTORY 43 




they multiply rapidly. If destruction is faster, the 
bacteria quickly die out. 

With inflation, the two competing processes are 
the decay of the false vacuum and its "reproduc- 
tion," because the inflating regions are expanding 
rapidly. Roughly speaking, the false vacuum decays 
because of random quantum mechanical fluctua- 
tions in the energy density of the vacuum. So to es- 
timate which process would win, I analyzed how 
the effects of quantum fluctuations compared to 
the rate of inflation. My analysis showed that false- 
vacuum regions multiply much faster than they 
decay. In other words, even though the false vac- 
uum is constantly decaying, inflation proceeds so 
rapidly that there is no way to stamp out the false 
vacuum everywhere in the universe at once. 

Many other big bangs went off 
before ours did, in remote parts 
of the universe. 

That result has extraordinary implications. In vast 
reaches of the universe, the ever-expanding wildfire 
that is inflation will never end; the volume of the 
inflating regions will keep growing forever, with- 
out bound. At this very moment, some distant parts 
of the universe are filled with false vacuum and are 
undergoing exponential inflationary expansion. 
Regions like ours, where inflation has ended, are 
also constantly being produced. They form "island 
universes" in the inflating sea of false vacuum. Be- 
cause of inflation, the space between the island uni- 
verses rapidly expands, making room for more is- 
land universes to form. Thus inflation is a runaway 
process that has stopped in our neighborhood but 
still continues in other parts of the universe, causing 
them to expand at a furious rate and constantly 
spawning new island universes like our own. 

Because the decay of the false vacuum and ensu- 
ing fireball occur repeatedly, the big bang loses its 
central status as a one-time event in the history of 
the universe. "Our" big bang gave rise to the stars 
and the galaxies we can see, as well as to many ob- 
jects beyond our visible horizon. But many other 
big bangs went off before ours did, in remote parts 
of the universe, and countless others will erupt 
elsewhere in the future. 

If cosmologists could somehow observe the in- 
flating universe from the outside, just as the sur- 
face of the Earth can be observed from space, they 
would see a multitude of island universes (regions 



of true vacuum) scattered in the vast inflating sea. If 
the entire universe is shaped like the three-dimen- 
sional analog of the surface of a sphere, the view 
that would open in front of them might resemble a 
globe, with continents and archipelagoes sur- 
rounded by ocean. The "globe" is expanding with- 
out bound at a staggering rate, the island universes 
are also growing exceedingly fast, and tiny new is- 
lands are constantly appearing and immediately 
starting to expand [see illustration on opposite page]. 

The inhabitants of island universes, like us, see a 
different picture. They do not perceive their universe 
as a finite island. For them it appears as a self-con- 
tained, infinite universe. That dramatic difference in 
perspective is a consequence of the differences im- 
posed by the ways of keeping time appropriate to the 
global and internal views of the island universe. (Ac- 
cording to Einstein's theory of relativity, time is not 
fixed, but depends instead on the observer.) 

When cosmologists talk about a "moment in 
time," they picture a large number of observers, 
equipped with clocks and scattered throughout the 
universe. Each observer sees a small patch of the 
universe, but the whole assembly is needed to de- 
scribe a large region. 

In the global view, the definition of a "moment 
of time" is largely arbitrary, because there is no ob- 
vious way to synchronize the clocks of observers 
across the false vacuum and in different island uni- 
verses. The number and the shape of the islands 
may differ, depending on this choice of definition. 
By contrast, to describe one specific island universe 
from the point of view of its inhabitants, there is a 
natural rather than arbitrary choice for the origin of 
time. All observers inhabiting the island universe 
can count time from the big bang at their respective 
locations. Their big bang is thus set as time zero in 
their entire island universe. Remarkably, from such 
an internal viewpoint the island universe is infinite. 

Perhaps the easiest way to see this is to count 
galaxies. In the global view, new galaxies are contin- 
ually formed near the expanding boundaries, so as 
time passes, the number of galaxies grows without 
bound. In the internal view, all those galaxies exist 
simultaneously (say, at time 14 billion years). 

The surprising feature of island universes — that 
they are infinite when viewed from the in- 
side — led me to what is perhaps the most striking 
consequence of eternal inflation. The analysis goes 
like this. Since each island universe is infinite from 
the viewpoint of its inhabitants, it can be divided 
into an infinite number of regions having the same 
size as our own observable region. My collaborator 
Jaume Garriga of the University of Barcelona and I 



44 



NATURAL history July/August 2006 



call them O-regions for short. As it hap- 
pens, the most distant objects visible from 
Earth are about 40 billion light-years away, 
so the diameter of our own O-region is 
twice that number. 

This fact might seem to imply that radia- 
tion from those distant objects left for our 
Milky Way before the big bang, about 14 
billion years ago. But actually, shortly after 
the big bang, the initial separation velocity 
between the matter that would become our 
Milky Way and the source of the radiation 
was enormous, far greater than the speed of 
light. Points in different parts of the uni- 
verse can separate from each other at speeds 
faster than light, because Einstein's ban on 
such speeds does not apply to geometric 
entities with neither mass nor energy. 
Today whatever was the source of the radi- 
ation 14 billion years ago has moved to 40 
billion light-years away. 

Imagine, then, an infinite island universe 
packed with gigantic spheres, each 80 billion 
light-years in diameter. Each sphere is an O-region. 
The spheres expand with the expansion of the uni- 
verse; the O-regions were smaller at earlier times. 
All the O-regions looked pretty much the same at 
the time of the big bang, or in other words, at the 
end of inflation. But they were different in detail. 
Small perturbations in density, brought about by 
random quantum mechanical fluctuations during 
inflation, differed from one region to another. 

As the perturbations were amplified by gravity, 
the macroscopic properties of O-regions began to 
diverge. By the time of galaxy formation, the de- 
tails of how galaxies were distributed from one O- 
region to another varied considerably — though sta- 
tistically the regions were still highly similar. Later 
on, the evolution of life and intelligence was influ- 
enced by chance, leading to further divergence of 
properties among the O-regions. The histories of 
distinct O-regions should thus be rather different. 

The key observation was that the number of dis- 
tinct configurations of matter that can possibly be 
realized in any O-region — or, for that matter, in 
any finite system — is finite. One might think that 
arbitrarily small changes could be made in the sys- 
tem, thus creating an infinite number of possibili- 
ties. But that is not the case. 

It I move my chair by one centimeter, I change 
the state of our own O-region. I could instead move 
it by 0.9 centimeter, 0.99 centimeter, 0.999 cen- 
timeter, and so forth — an infinite sequence of pos- 
sible displacements, which more and more closely 
approach the limit of one centimeter. There is ,\ 




4 




Big bangs 

Barren oldest regions 
Star-filled newer regions 
False vacuum 



Island universes condensing out of a region of the inflating "master" universe are 
depicted schematically at two successive times, one (left) earlier than the other (right), 
as they might appear if they could somehow be observed from the "outside. " Existing 
island universes enlarge and new ones form as the false vacuum decays, giving rise to 
big bangs at the peripheries of the islands and at random places amid the inflating 
sea. The hot, dense matter created in the big bangs coalesces into stars and galaxies, 
while central parts of the large islands are extremely old, and thus dark and barren. At 
the same time, the sea of false vacuum expands even faster than the islands do, mak- 
ing room for new islands to form. The diagram is based on a computer simulation. 



problem, though. Displacements too close to one 
another cannot be distinguished, even in principle, 
because of quantum mechanical uncertainty. 

In classical, Newtonian physics, the state of a 
physical system can be described by specifying the 
positions and velocities of all its constituent par- 
ticles. But because of the underlying reality of quan- 
tum mechanics, such a description can apply only to 
massive, macroscopic objects, and even then, only 
approximately. In the quantum world, particles are 
inherently fuzzy and cannot be localized precisely. 

Since the precise positions of particles cannot be 
pinned down, one can resort instead to a so- 
called coarse-grained description. Suppose the vol- 
ume of our O-region is divided into cubic cells of a 
certain size, say one cubic centimeter each. You can 
specify a coarse-grained physical state by indicating 
the cell occupied by each particle in the region. To 
make a more refined description, you just make the 
cells smaller, say, a cubic nanometer. But this kind 
of refinement has its limits, because there is a quan- 
tum mechanical energy cost of localizing particles 
to small cells. That cost will eventually exceed the 
available energy in the O-region. 

Evidently, the number of ways a finite number of 
particles can be distributed into a finite number of 
cells is also finite. Hence the material content of 
our O-region can take on only a finite number of 
distinct states. A very rough estimate of this num- 
ber gives 1(1 to the power 10 , or I followed by 
l<>'"' zeros. This number is fantastically huge, too 



July/August 2006 NATURAL HISTORY 



4 5 



Exact replica of our Earth 
is populated by clones. 



You are here 




Earthlike planet has collapsed 
to form a black hole. 



Dinosaurs still reign because no 
asteroid hit this earthlike planet. 



Island universe in which we live encompasses infinitely many ob- 
servable regions, or "O-regions, " each the size of our observable 
universe. Each sphere in the schematic diagram represents a re- 
gion whose radius is equal to the distance from Earth to the most 
distant objects we can see: about 40 billion light-years. The Earth 
lies inside one such O-region. Because of the "graininess" of space 
and time in quantum mechanics, the number of possible histories 
of all the particles inside such a region, beginning with some fixed 
moment in the past, is finite (though, of course, huge). Since the 
number of O-regions is infinite, every possible history — a world in 



which Earth collapses to form a black hole, for instance, or a world 
in which the dinosaurs still survive — is replayed in an infinite num- 
ber of O-regions, the closest ones at least a googolplex (10 to the 
power 10 wo ) light-years away. The O-regions are all shown at the 
same time after the big bang, which corresponds to an "internal 
view" of the island universe. The internal view is used only to por- 
tray the O-regions that make up part of the interior of one island; 
the other islands would not be visible in a consistent diagram, but 
in the "global view" that has been overlaid on this drawing, several 
other island universes appear. 



big even to be written down in standard notation 
with digits of ordinary size on paper that could be 
fitted into the part of the universe we can observe. 
But the important point is that the number is finite. 

Not only is the number of possible states of an O- 
region finite; the number of its possible histories is 
finite as well. A history is described by a sequence of 
states at successive moments of time. Which histories 
are possible in quantum physics differ immensely 
from the ones possible m the classical world. In the 
quantum world the same initial state can lead to a 
multitude of outcomes to which only probabilities 
can be assigned. Consequently, the range of possible 
histories is greatly enlarged. 

Once again, though, the fuzziness imposed by 
quantum uncertainty makes it impossible to distin- 
guish histories that are too close to each other. The 
histories of various O-regions can be distinguished 
only if the successive moments in the histories are 
separated by sufficiently large (though still tiny) inter- 
vals of time. Giving such a coarse-grained history is 
much like recording a movie in a digital format: you 
simply specify the cell "addresses" for all the particles 
in the O-region at each moment in the finite se- 
quence ot intervals. Any finite number of states, each 
specified for a finite number of moments, yields only 
a finite number of distinct histories of the system. 

Garriga and I did a quick, back-ot-the-envelope 
estimate of the number of possible histories that can 
unfold in an O-region between the big bang and the 
present. As one might expect, we got yet another 
"googolplexic" number: 10 to the power 10 (a 
googolplex is 10 to the power of a googol). The ac- 
tual numbers of the quantum states and of possible 
histories in an O-region are not particularly impor- 
tant, but the fact that those numbers are finite has 
far-reaching implications, indeed. 

It may be helpful to take stock of the cosmic story 
so far. It follows from the theory of inflation that 
island universes are internally infinite, so that each 
of them comprises an infinite number of O-regions. 
And it follows from quantum uncertainty that only 
a finite number of histories can unfold in any O- 
region. Putting those two statements together, it 
follows that every single possible history should be 
repeated an infinite number of times within any of 
the island universes — including, of course, the one 
we inhabit. In quantum mechanics, anything not 
strictly forbidden by the conservation laws of 
physics must happen — and has happened — in an in- 
finite number of O-regions. 

Among the infinitely replayed scripts are some 
very bizarre histories. For example, a planet similar 
to our Earth can suddenly collapse to form a black 



hole. Such an event is extremely unlikely, but all that 
means is that, before encountering it, one would, in 
all probability, have to survey an enormous number 
of O-regions within our island universe. 

A striking consequence of the new picture of the 
world is that among the infinite number of O-re- 
gions is an infinite subset of those regions with his- 
tories absolutely identical to ours. Yes, dear reader, 
scores of your duplicates are now reading copies of 
this article. They live on planets exactly like Earth, 
with all its mountains, cities, trees, and butterflies. 

How far away are these earths populated by our 
clones? Matter in our O-region can assume about 



With humankind reduced 
to absolute cosmic insignificance, 
our descent from the center 
of the world is now complete. 




10 to the 10 90 distinct states. A box large enough 
to hold, say, a googolplex O-regions should exhaust 
all those possibilities by a large margin. Such a box 
would be roughly a googolplex light-years across. At 
greater distances, O-regions, including ours, should 
recur. There should also be regions whose histories 
differ from ours, with all possible variations. They all 
belong to the same spacetime, and given enough 
time, our descendants might, in principle, be able to 
visit the inhabitants of another O-region. 

But we will never be able to reach another one of 
the island universes (each with its own infinite com- 
plement of O-regions), or even send a message 
there. The reason is that no one will be able to keep 
up with the boundaries of the island universe, 
which are expanding faster than the speed of light. 
Thus, we will never be able to reach the shores of 
the inflating sea and bask in the light of the new 
suns that will be born there. We cannot even pro- 
claim our own existence to the future civilizations 
that will thrive around these suns. 

Regardless of their accessibility, other universes 
and other O-regions will surely change our larger 
sense of place. In the worldview that has emerged 
trom the ideas of eternal inflation, our civilization 
is anything but unique. Instead, countless identical 
civilizations are scattered across the cosmos. With 
humankind reduced to absolute cosmic insignifi- 
cance, our descent from the center of the world, a 
process begun by Copernicus (in this world and on 
countless others) is now complete. □ 

This article was adapted from Many Worlds in One: I he Search for 
Other Universes, by . Ilex I ilenkin, which is being published in July 
by Hill and Wang, 



July/August 2006 NATURAL HISTORY 



47 



BOOKSHELF: SUMMER READING 



By Laurence A. Marschall 



Science Most Foul 



Summertime, and the reading is easy. You don't escape to the beach or the mountains 
to fritter away your lazy hours fretting about the pollution of the Arctic or the effects 
of invasive species on Hawaiian biodiversity. No, what you want is a healthy homicide. 
It's best if the crime is outrageous, the suspects menacing, and the investigator both noble 
and quirky. Still, there's no reason not to mix in a little science with the mayhem. After 
all, wasn't Sherlock Holmes a master chemist, and Watson a trained physician? 

Everyone has perennial choices, I'm sure. High on my list would be almost any nov- 
el by Nevada Ban, whose crime-stopping park ranger Anna Pigeon seems to have worked 

at most of the great scenic 
wonders of North America. 
Less well known, but equal- 
ly entertaining, is Morgan 
O'Brien, the creation of the 
Canadian novelist Alex 
Brett. O'Brien may be one 
of the few detectives whose 
specialty is scientific-research 
fraud, and her latest adven- 
ture, Cold Dark Matter 
(2005), authentically set in a large mountaintop observatory, involves murder, mayhem, 
and, not incidentally, spectroscopy of distant galaxies. 

Thankfully, there seems to be no shortage of writers who can artfully blend mystery 
and science. Among the most enjoyable new publications that have graced my nightstand 
in recent months are these prime candidates for summer fun: 




Unnatural Selection by Aaron Elkins 
(Berkley Books; $23.95) 

Gideon Oliver, forensic anthropolo- 
gist extraordinaire, makes his thirteenth 
appearance in this latest novel by Edgar 
Award— winner Aaron Elkins. The set- 
ting is pure Agatha Christie: a brood- 
ing castle in the Isles of Scilly, off the 
Cornish coast of England, where a small 
group of environmental experts — in- 
cluding Gideon's spouse, Julie, an ex- 
pert on wildfire management — have as- 
sembled for a weeklong brainstorming 
session hosted by an eccen- 
tric Russian entrepreneur. 
While Julie deals with the in- 
flammable mix of personali- 
ties at the daily colloquia, 
Gideon kills time examining 
artifacts at the local museum. 
Mixed in with the museum's 
prehistoric skeletal remains, he 
discovers, is a human bone that, 
to his trained eye, shows signs of 
murder most foul. Soon more 



bones show up on a local beach, and it 
becomes clear that they all belong to the 
victim of a brutal dismemberment that 
took place a bit more recently than the 
Bronze Age. There is no record, how- 
ever, of any local person gone missing. 
So whose bones are they? 

As Gideon ponders the evidence and 
the local police chief investigates, the fog 
rolls in and the fog rolls out. Tempers 
flare and passions simmer among the 
invitees at the castle. Then, one mist- 
shrouded midnight, a par- 
ticipant in the workshop 
is forcibly precipitated 
from a parapet. Could 
there be a connection 
between this murder 
and the dismembered 
bones? Well, of course 
there is, but you must 
resist the temptation to 
leapfrog to the oblig- 
atory scene in which 
all the assembled sus- 




pects find out which of them is guilty. 
The pleasure of summer reading lies not 
in resolution but in investigation, and 
Elkins keeps things moving with plen- 
ty of local atmosphere, compelling 
characterization, and a refreshingly low 
level of violence. CSI: Miami it's not, 
but it would make a lovely episode on 
the BBC Mystery Monday series. 

The Darwin Conspiracy by John Darn- 
ton (Alfred A. Knopf; $24.95) 

After five vigorous years aboard the 
H.M.S. Beagle, Charles Darwin re- 
turned to England a broken man. His 
mind was sharper than ever, to be sure, 
and many decades of groundbreaking 
research and writing lay ahead, but his 
body was already beginning to fail. For 
the rest of his life he complained of nau- 
sea, vomiting, flatulence, skin rashes, 
headaches, vertigo, and countless other 
maladies. For all of them he sought 
remedies that, given the primitive state 
of medicine at the time, may have done 
him more harm than good. At various 
times Darwin dosed himself with opi- 
um, shocked himself with electricity, 
and wrapped his body with towels 
soaked in freezing water — all to no avail. 

Darwin's illness is a real historical 
mystery: How could a young man who 
galloped on horseback over the Pam- 
pas and backpacked (sans Gore-Tex) in 
the Andes, turn so prematurely into an 
elderly invalid, obsessed with rampant 
bodily dysfunctions? 

To the shelf of scholarly mono- 
graphs addressing this question, vaca- 
tion readers should welcome The Dar- 
win Conspiracy, a fast-paced novel of 
romance and intellectual intrigue by 
John Darnton, who was editor and 
foreign correspondent for The New 
York Times. Its protagonists are Hugh 
Kellem, an anthropologist, and Beth 
Dulcimer, an evolutionary biologist, 
whose pursuit of the Darwinian lore — 
and of each other — begins on a remote 
island of the Galapagos, amidst the 
finches that helped inspire the theory 
of natural selection. 

The two return to England and be- 
come fascinated with the hidden threads 



48 



NATURAL HISTORY July/August 2006 



of Darwin's life, aided 
by the fortuitous dis- 
covery of a series of 
journals written by 
Darwin's daughter 
Lizzie. There are a 
few side plots, and 
numerous flash- 
backs re-creating 
Darwin's travels 
on the Beagle, but most of the 
detective work here is of the academic 
sort, carried out in dimly-lit archives, 
vaguely suggestive of The Da Vinci Code, 
but nowhere near as ominous. 

If you're a Darwin buff, you may find 
much of Darnton's narrative familiar, 
since he has scrupulously mined infor- 
mation from Darwin's journals and let- 
ters as well as from the many Darwin 
biographies written over the years. But 
the writing is snappy and smart, and the 
final diagnosis of Darwin's debility is so 
audacious and amusing that even the 
most jaded summer reader will regard 
the few hours unraveling The Darwin 
Conspiracy as time well spent. 

The Book of the Dead by Douglas 
Preston and Lincoln Child (Warner 
Books; $25.95) 

Most of the action of this gothic 
tale of Gotham takes place in the 
remote galleries of the "New York 
Museum," a thin disguise for the 
American Museum of Natural 
History at Central Park West and 
Seventy-ninth Street. But that's 
plenty of real estate, considering that the 
fictional museum includes thirty-four 
interconnected buildings with more 
than 2 million square feet of space and 
more than eighteen miles of corridors. 
Most of the collection has never been 
seen by the public, including (accord- 
ing to Douglas Preston and Lincoln 
Child) the Tomb of Senef, a colossal 
Egyptian monument imported stone by 
stone in the 1 800s, but sealed off for 
more than three-quarters of a century. 

Archaeologist Nora Kelly is in charge 
of renovating the tomb for a new exhi- 
bition, partly to burnish the reputation 
of the museum, which has been shak- 



en by a recent murder and the theft of 
its entire diamond collection by arch- 
fiend Diogenes Pendergast. But there is 
much more bloodshed to come, as the 
master criminal unfolds his plan to ter- 
rorize the rich and powerful of New 
York City at the official opening of the 
new exhibition. Only one man can stop 
the impending catastrophe: Diogenes' 
older brother, F.B.I. Special Agent 
Aloysius X.L. Pendergast. Alas, Aloy- 
sius is locked up in a federal maximum 
security cell, framed for a murder his 
brother committed. Is all hope lost? 

Not to worry. Agent Pendergast, 
whose crime-fightmg skill makes 
Sherlock Holmes look like Inspector 
Clouseau, has his own plan. With the 
help of a group of lower Manhattan ir- 
regulars, he busts out of stir just in time 
to stop the massacre of the innocents 
and to track down his evil sibling. 

I doubt I've given too much away. 
Agent Pendergast and his crew have ap- 
peared in several best-selling novels by 
Preston and Child, and by the rime 
The Book of the Dead 
opens, he's al- 
ready pursued 





the incorrigi- 
ble Diogenes 
through Brim- 
stone and Dance of 
Death. A short re- 
view can hardly do 
justice to the large 
cast and relentless 
pace of action of the 
trilogy, but be warned, 
^" once you start reading, 
it will be hard to stop. The characteri- 
zation never rises above the level of car- 
icature, to be sure, and the plotting is 
never less than over-the-top. But isn't 
that reason enough to put it on your 
summer list? 

The Oxygen Murder by Camille Mini- 
chino (St. Martin's Minotaur; $24.95) 

Not many murder mysteries arc illus- 
trated by diagrams of inorganic mole- 
cules, but that seems entirely appropri- 
ate if the crime involves Gloria Lameri- 
no, a retired Berkeley physicist current lv 




A Sand County Almanac f 



JULIANNE LUTZ NEWTON 

jfeALDO 

Leopold's 

ODyssEy 



July/August 2006 NATURAL history 49 




"There are two things that 
interest me: the relation of 
people to each other, and the 
relation of people to land." 
— Aldo Leopold 

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new generation 

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residing in the north Boston suburb of 
Revere. This time around, she's in New 
York City, doing Christmas shopping, 
enjoying the cuisine ofLittle Italy, and, 
incidentally, trying to find the killer 
of a cinematographer found suffo- 
cated in the midtown apartment of 
her husband's niece. The niece, it 
turns out, is making a documen- 
tary about ozone (O,) pollution 
in the workplace, and it could be that 
one of the business establishments she 
was spotlighting took drastic measures 
to conceal their violations of environ- 
mental law Then again, it could have 
been one of the people her cinematog- 
rapher was blackmailing. 

At first read, Lamerino seems more 
like an Italian grandmother than a hard- 
nosed detective. She's a reluctant inves- 
tigator, driven mostly by curiosity and 
the need to do something with her brain 
now that she's no longer in the lab. Afraid 
of guns, she even worries herself into a 




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tizzy when 
she pilfers an 
incriminating 
document from 
a suspects filing 
cabinet. But give 
er a PowerPoint 
presentation or a 
chalkboard, and she 
hits her stride. Two- 
or three-page science 
lectures immediately 
come forth, such as 
how CFCs harm the ozone layers, that 
read as if they were lifted from a text- 
book. And, pushed into action, she's 
sharp-eyed and resourceful, and she al- 
ways seems to come through her in- 
evitable encounters with perps suffering 
only minor injuries. 

That's fortunate, because Lamerino 
has a remarkable proclivity for encoun- 
tering crimes. She's solved seven "ele- 
ment" murders before this one, starting 
from the top of the periodic table: hy- 
drogen, helium, lithium, beryllium, 
boron (well, actually, boric acid), car- 
bon, and nitrogen. 

The pattern was no doubt inspired by 
Sue Grafton, whose "Alphabet" series, 
featuring detective Kinsey Millhone, is 
up to "S" (Sis for Silence). But if Camille 
Minichino's pattern continues, she'll be 
writing a lot longer than Grafton will, 
since the number of naturally occurring 
chemical elements (ninety-two) is a 
good deal greater than the number of 
letters in the alphabet. If Minichino, like 
Gloria Lamerino, is looking forward to 
an easy and crime-free retirement, she's 
out of luck — which is very good news 
for summer readers. 

Also Worthy of Mention: 
Intuition by Allegra Goodman (The Dial 
Press; $25.00) 

Like Goodman's earlier books, Intu- 
ition is a literate and perceptive explo- 
ration of human relations, not a pure 
entertainment. It's set in a lab in Cam- 
bridge, Massachusetts, where a young 
postdoc is embroiled in a controversy 
over falsifying data. There's mystery and 
conflict, along with a sharply drawn 
cast of characters, just as in the genre 



mysteries. But this is a lovely book that 
readers wiD find not a guilty pleasure, 
but a pure delight. 

Quarry by Susan Cummins Miller (Texas 
Tech University Press; $24. 95) 

The geologist heroine is just about 
to defend her thesis, when one of her 
doctoral examiners is murdered. And 
that's just the start of this fast-moving 
and authentic thriller that effectively 
conveys the feel of geological field- 
work along with its high-adrenaline 
plot line. Geologist MacFarlane is 
making her third outing here, and she 
clearly ranks among the upper strata of 
scientifically trained detectives. 

Laurence A. Marschall, author of The 
Supernova Story, is W.K. T. Sahm Professor 
of Physics at Gettysburg College in Pennsylva- 
nia, and director of Project CLEA, which pro- 
duces widely used simulation software for edu- 
cation in astronomy. 

LETTE RS 

(Continued from page 10) 
the atmosphere, as much as all the cars 
and light trucks in the United States." 

The Centralia, Pennsylvania, mine 
fires have been burning since 1962. 
The Jaharia mine fires in India have 
been burning since 1916. The con- 
tribution of those fires to global emis- 
sions of carbon dioxide should be a 
part of any thoughtful discussion on 
climate change. 
David Hutchins 
Ocean Ridge, Florida 

I applaud your printing of Jeff Good- 
ell's "Commentary" and especially 
your giving it the cover priority it de- 
serves. In the many years I have read 
your publication, Natural History has 
displayed consistently first-class jour- 
nalism. With this article, however, you 
are taking a bold step and a desperate- 
ly needed stand on the major issue of 
this century: climate change and oth- 
er environmental disasters. I say this 
sadly, because those of us involved in 
these issues know how radically the 
(Continued on page 52) 



50 



NATURAL HISTORY July/August 2006 



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LETTERS 

human race must refocus and rethink 
its priorities. 
Jon Dcak 
New York, NY 

Jeff Goodell's article was based on min- 
imal facts and pseudoscience, and I was 
shocked that you would publish it. I am 
a geologist and know of the lack of cor- 
relation between climate and carbon 
dioxide. I am also involved with min- 
ing, so am aware of the fanciful de- 
scriptions Goodell had of mountaintop 
mining. The errors in his article are eas- 
ily spotted: 1,000-foot-thick surface 
mines, 400,000 acres of forest lost, and 
700 miles of streams destroyed. 
Ken Fishel 
Lexington, Kentucky 

Jeff Goodell replies: The 400,000 
acres of forest lost and 700 miles of 
streams destroyed, data that Ken Fishel 
dismisses as erroneous, are well-docu- 
mented in an exhaustive report on 
mountaintop mining issued by the U.S. 
Environmental Protection Agency in 
October 2005. As for the "1,000-foot- 
thick surface mines," the photo caption 
simply describes how workers "blast 
away the uppermost 800 to 1,000 feet 
of rock to expose layers of coal within." 
The truth of this is apparent to anyone 
who glances at a photograph of a big 
surface mine, much less has been per- 
sonally involved in the mining industry. 

Finally, as for the "lack of correla- 
tion between climate and carbon 
dioxide," I presume Mr. Fishel grasps 
the basic physics of the greenhouse ef- 
fect, and that what he really is talking 
about is the complexity of the correla- 
tion between climate change and car- 
bon dioxide — a subject that was, alas, 
beyond the scope of my brief article 
about coal. 

Natural History welcomes correspondence 
from readers. Letters should be sent via 
e-mail to nhmag@naturalhistorymag.com 
or by fax to 646-356-651 1. All letters 
should include a daytime telephone number, 
and all letters may be edited for length 
and clarity. 



52 



NATURAL HISTORY July/August 2006 



nature.net 

Reptilophilia 

By Robert Anderson 

I've never been much for pets — too 
much responsibility. Once, though, 
when a herpetologist friend offered me 
a turtle that had been turned over to 
him by customs agents, I said yes. A vic- 
tim of the illegal pet trade, it was a 
big-headed turtle (Platysternon mega- 
cephalum, similar in appearance to New 
World snappers) that had flown in from 
the wilds of Southeast Asia to New 
York City before it was confiscated. My 
turtle was an admirable beast with a 
powerful, hooked beak to crack open 
crustaceans and mollusks. He was also 
adept at stalking small fish. "Jaws" — I 
guess the name was inevitable — taught 
me that, in the end, turtles can be light- 
ning fast (you can see photographs of 
his species at the turtle site chelonia.org/ 
platysternon_gallery.htm). 

Jaws gave me an appreciation for tur- 
tles, and for reptiles in general, a group 
with more than 8,000 known living 
species. Go to the Reptile Database at 
the European Molecular Biology Lab- 
oratory in Heidelberg, Germany 
(www.embl-heidelberg.de/~uetz/LivingRep 
tiles.html) and click on "How many spe- 
cies?" for a breakdown of the clan and 
a link to a map showing its global dis- 
tribution. Nearly a quarter of all reptile 
species are harmless colubrid serpents, 
which include garter snakes. The sec- 
ond greatest number ot species are the 
skinks, followed by the geckos. The 
only two surviving species of an entire 
reptilian order, the tuataras, live on is- 
lands off the coast of New Zealand. 
Both are endangered, and climate 
change may finish them off (news.bbc.co. 
uk/1/hi/sci/tech/1 896463. stm). The Cen- 
ter for North American Herpetology 
(cnah.org) has links to comments on the 
taxonomy and photos of local species. 

Although reptiles are popular as pets 
and in zoos, real enthusiasts enjoy spot- 
ting them in the wild. At the Web site 
of Mike Pingleton, an amateur her- 
petologist (pingleton.com), click on 
"Notes from the Field" to read about his 



adventures tracking down hundreds of 
species of frogs, lizards, snakes, and tur- 
tles. Another intriguing site (flying 
snake.org) may not be for everyone, par- 
ticularly if serpents give you the willies. 
Movie clips document how certain 
Southeast Asian tree snakes propel 
themselves through the air, gliding from 
branch to branch [see "Serpents in the 
Air," by Adam Summers, May 2003]. 

You can learn a lot about human bi- 
ology from the differences and similar- 
ities between reptiles and mammals. 
What are the advantages of being 
hot- or cold-blooded? Go to NASA's 
"Infrared Zoo" (coolcosmos.ipac.caltech. 
edu/image_galleries/ir_zoo/coldwarm. 
html) for an illustrated discussion of the 
various approaches to regulating body 
temperature. 

Thermal regulation and other dif- 
ferences aside, human beings share 
much with reptiles. Unlike amphibians, 
which must remain in water to repro- 
duce, reptiles were the first animals to 
have eggs with an amniotic sac, which 



enabled them to fully conquer land. 
At the Tree of Life Web site (tolweb.org/ 
Amniota), you can read more about how 
reptiles paved the way for later verte- 
brates. Dinosaurs, birds, and mammals, 
all with an amniotic sac, are all descen- 
dants of early reptiles. 

Another bit of anatomy people in- 
herited from reptiles is the core of the 
brain. At the Web site of the Canadian 
Institute of Neurosciences, Mental 
Health and Addiction (www.thebrain. 
mcgill.ca) is a brief description of the 
"three" human brains: the reptilian 
brain, the limbic brain, and the neocor- 
tex. An interactive diagram at www.brain 
channels.com/evolution/physicalbrain.html 
#Anchorreptilian gives more detail. Some 
mental-health problems are rooted in 
our reptilian brains (www.psycheduca 
tion.org/emotion/R%20complex.htm), so 
you may want to blame your obsessive- 
compulsive disorder ... on your turtle. 

Robert Anderson is a freelance science 
writer tiring in Los Angeles. 




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July/August 2006 NATURA1 HISTORY 



53 



OUT THERE 



Deceptive 
Nebulous 
Apparition? 

The double helix 

at the center of the galaxy 



By Charles Liu 

Appearances can be deceiving — 
especially in outer space. Thir- 
ty years ago, the Viking 1 or- 
biter took thousands of photographs of 
the Martian surface: craters, canyons, 
mountains, and more. The peaks and 
shadows of one mountain evoked a 
fuzzy, mile- wide human face. For the 
next quarter century, folks with vivid 
imaginations — including some who 
were pretty handy with image-enhanc- 
ing software — insisted that this geolog- 
ical oddity was evidence of intelligent 
life on Mars. Finally, in 2001, high- 
resolution images made by the Mars 
Global Surveyor laid their speculations to 
rest: the first "face" was a coincidental 
confluence of light and shadow. The 
mountain was really just a mountain. 

But you can't blame people whose 
eyes led them to an anthropomorphic 
conclusion. They were far from the 
first, even among Mars-watchers. A 
century ago the American astronomer 
Percival Lowell thought he saw a vast 
network of artificial canals on the Mar- 
tian surface, and his sketches and spec- 
ulations created a sensation. 

Such misinterpretations happen all 
the time, according to psychologists. 
The human tendency to translate ran- 
dom sensory input into familiar shapes 
is an important cognitive process. It 
helped early humans recognize preda- 
tors and other threats in the environ- 
ment. It also helps explain why people 




of molecular gas — picture 
the rings of Saturn, 
but a lot bigger and 
even more chaot- 
ic. The second, 
outer disk is 
about twenty 
light-years 
across. With- 



have given con- 
stellations, star clusters, 
and nebulae the names of gods, humans, 
animals, and other terrestrial objects. 

So it's understandable that today, 
when genetics and biotechnology loom 
large in our coDective consciousness, as- 
tronomers have dubbed one recent dis- 
covery the Double Helix Nebula. That 
object, a coiling jet of glowing gas — 
spied with an infrared eye by a team of 
astronomers led by Mark R. Morris of 
the University of California at Los An- 
geles — looks a lot like a strand of DNA. 
This striking corkscrew structure is a 
mere 200 light-years away from the nu- 
cleus of our galaxy, and it may well em- 
anate from that enigmatic middle of the 
Milky Way — where a gaseous spiral, a 
disky gaseous ring, a swarm of hot 
young stars, and a supermassive black 
hole all lurk behind a deep, dense screen 
of dusty gas. 

Even without a glowing double 
helix sticking out of it, the galac- 
tic center is a weird place. For starters, 
its black hole, known as Sgr A* (yes, 
the asterisk is part of the name), weighs 
in at a hefty 3.5 million times the mass 
of our Sun. A swirling whirlpool-like 
disk of hot, ionized gas, complete with 
spiral arms that sorta-kinda mimic the 
larger galaxy in which it resides, is cen- 
tered on the black hole. Beyond this 
disk lies another thin disk primarily 



in, among, 
and above 
those gaseous 
structures are 
surprisingly 
large numbers 
of hot, massive 
stars that are much 
younger than the stars 
you'd expect to find near 
a supermassive black hole. 
How does the Double Helix Neb- 
ula fit into this picture? Well first, con- 
sider how it was found, a good clue to 
its identity. It was captured with the aid 
of the Spitzer Space Telescope (SST), 
which detects infrared light. Infrared, 
which is invisible to human eyes but de- 
tected by human skin as heat, has longer 
wavelengths than visible light and can 
penetrate substantially thicker screens of 
dust than visible light can. That makes 
the SST an ideal tool for studying the 
Milky Way's galactic center, whose vis- 
ible light is almost completely quenched 
by intervening, obscuring dust. 

Morris and his colleagues had been 
looking for infrared emissions at a wave- 
length of about twenty-four microns. 
That's the wavelength at which inter- 
stellar dust emits its greatest heat, if it's 
at a temperature of —240 degrees 
Fahrenheit. To their surprise, they no- 
ticed a pattern that looked a lot like a 
double helix. Given the temperature of 
the pattern, it had to be a stream of dusty 
gas, more than 1 00 light-years long and 
about 200 light-years from Sgr A*. 

But could the double helix be an- 
other face-on-Mars illusion, perhaps 
created by a chance superposition of 
glowing gas? Probably not. There's 
good reason to think the object has a 
coherent physical structure. For one 
thing, it wasn't an isolated discovery. 
Like the discoverers of Pluto's two 



NATURAL HISTORY July/August 2006 



newest moons [see "Sizing Up Pluto," by 
Charles Liu, May 2006] , Morris and his 
collaborators looked through astro- 
nomical archives to confirm their ob- 
servations. They found that more than 
a decade ago the Midcourse Space Ex- 
periment (MSX) had detected the 
glowing strand, which extends some 
100 light-years at nearly right angles 
from the plane of the Milky Way If you 
squint really hard at the MSX image, 
you can just make out the fuzzy out- 
line of a double helix; because MSX 
didn't have the resolving power of the 
SST, however, the structure wasn't vis- 
ible to anyone who didn't already know 
to look for it. 

Fine. The double-helical coil is out 
there. Now the obvious question: 
how'd it get there? 

Whenever we astronomers see twists 
and braids, we think right away of two 
things: rotation and magnetic fields. 
When an electrically charged celestial 
object spins, it often generates a mag- 
netic field. Sometimes, cone-shaped 
magnetic channels lead 
from the object's north 
and south poles. If the ro- 
tation is rapici and the field 
is strong, those channels 
can direct the flow of 
electrically charged mat- 
ter. That flow manifests 
itself in many phenome- 
na — from the gentle cas- 
cade of solar wind toward 
Earth's poles, which pro- 
duces the northern and 
southern lights, to the 
superenergetic outflows 
of quasars, which can 
generate more energy in 
a second than the Sun 
does in a million years. 

Morris and his col- 
leagues suggest that the 
double helix could be a 
magnetic "torsional Alf- 
ven wave," generated by 
a flattened, electrically 
charged, spinning gaseous 
structure. The structure 
could be the disklike ring 



of molecular gas that encircles Sgr A*. 
It's about the right size for the job — a 
little more than twice the width of the 
double helix — and it spins around the 
black hole at a more-than-adequate 
200,000-plus miles per hour. Dust par- 
ticles blown upward from the vicinity of 
the ring would become ionized by ul- 
traviolet radiation; those particles, now 
electrically charged, would follow along 
the magnetic field lines that trace the 
torsional wave. The particles' infrared 
glow, picked up by the SST, would ap- 
pear as a delicate, double-helix structure. 

There are a few bugs in this picture, 
though. For one thing, between 
the bottom of the double helix and the 
molecular ring around the galactic cen- 
ter is a gap of more than 100 light-years. 
For another, the double helix doesn't 
point directly at the ring. Moreover, 
since there are always two magnetic 
poles, a second double helix should be 
protruding downward, perpendicular 
to the ring in the opposite direction. 
But there's only one. 




Infrared image of the central region of our galaxy was made by the 
Spitzer Space Telescope (SST). The detail (top of opposite page) shows 
the recently discovered Double Helix Nebula, about 100 light-years long; 
that image was also obtained with the SST, but at a longer infrared 
wavelength. The origin of the double-helix structure may be a coil-shaped 
magnetic wave emanating from a flattened, spinning ring of gas near the 
black hole at the galactic center. Both black hole and ring are hidden from 
view within the bright white dot near the center of the image above. 



Here's another complication. Can a 
delicate torsional wave persist long 
enough to form a double helix that 
keeps its shape through the rough- 
and-tumble galactic center and con- 
tinues twisting evenly hundreds of 
light-years beyond that? 

One example of how dynamic things 
can get comes from a recent study by 
Angelle M. Tanner of the Jet Propul- 
sion Laboratory in Pasadena and sever- 
al colleagues (including Morris). Tan- 
ner's team showed that the stars with- 
in two light-years of Sgr A* — that is, 
closer to the black hole than to its en- 
circling gaseous ring — appear to orbit 
in roughly the same orientation. But 
unlike the nearby molecular gas, they're 
not arranged in a ring. Tanner says the 
stars' scattered arrangement suggests 
they formed elsewhere and were pulled 
into the neighborhood rather recently; 
their "migration" may well have dis- 
turbed or disrupted a torsional wave. 

Another contributor to the dy- 
namism of the galactic center is the 
unstable nature of the gaseous ring it- 
self; huge amounts of gas 
continuously flow in and 
out of it, which could 
make the structure of its 
magnetic field too variable 
to sustain a prolonged tor- 
sional wave. 

Until investigators do 
detailed supercomputer 
simulations, there probably 
won't be a complete expla- 
nation of the Double Helix 
Nebula. But I wouldn't be 
surprised if, years from 
now, its portrait becomes an 
icon in the gallery of as- 
tronomy. Like the face on 
Mars, it's a striking image. 
Unlike that face, though, 
this picture may actually 
shed light on the mysteries 
of the cosmos. 



Charles Liu is a professor of 
astrophysics at the Cay ( Universi- 
ty of New York and an associate 
with tlw American Museum of 
Natural History. 



July/August 2006 NATURAi HISTORY 




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52. NEW MEXICO 

Where unparalleled scenic beauty, 
outdoor adventure, world -renowned art 
and cultural diversity rest under the 
same magical sunset. 

53. NEW YORK STATE 

Plan your next getaway to New York 
State! I LOVE NEW YORK! What a 
great vacation. 

54. NORTH CAROLINA OUTER BANKS 

The Outer Banks of NC — Immerse 
yourself in culture and history. Here 
anytime is quality time. 

55. THE GREAT STATE OF TEXAS 

Discover a vacation you nev er knew 
existed. Discover mountains, prairies, 
open skies and endless coastlines. 
Discover it all in your FREE Texas State 
Travel Guide. Discover why Texas really 
is like a whole other country. 

56. TUCSON 

Tucson, Real. Natural. Arizona. 
Discov er a w hole new side of nature in 
our fascinating desert landscape. And 
the weather's perfect for exploring our 
spectacular scenerv any time of year. 



THE SKY IN JULY AND AUGUST 



By Joe Rao 



Mercury is too dim and too close to the 
Sun to see until the last few days of Ju- 
ly. It passes through inferior conjunc- 
tion, between the Earth and the Sun, 
on July 18 and moves into the morn- 
ing sky. Look for it at the end of the 
month, low in the east-northeast sky 
about forty-five minutes before sunrise. 

In August this speedy planet makes a 
fine morning apparition, as it gains alti- 
tude and reaches its greatest western 
elongation on August 7. On that morn- 
ing it shines at magnitude +0.1 and ris- 
es nearly ninety minutes before sunup. 
During the next two weeks Mercury 
slowly drops back toward the Sun, but 
as if to compensate, it grows progres- 
sively brighter. On the mornings of 
the 9th and 10th you'll find Mercury 
roughly two degrees below brilliant 
Venus. Then, on the morning of the 
20th, Mercury shifts to just a little more 
than one degree above Saturn. Two 
mornings later, a slender crescent Moon, 
less than thirty-six hours from its new 
phase, appears to hover weD above Mer- 
cury. By then, Mercury brightens to 
magnitude —1.4, matching Sirius, the 
brightest star in the sky. For the rest of 
the month it disappears into the dawn. 

Venus shines brilliantly at magnitude 
—3.8 in the morning sky. From the be- 
ginning of July through the middle of 
August it rises out of the east-northeast 
sky just as dawn breaks. In August it 
passes a couple of degrees above Mer- 
cury on the mornings of the 9th and 
10th. In the second half of August it 
loses altitude noticeably as it begins its 
plunge back toward the Sun. A nar- 
rowing crescent Moon slides past Venus 
on the mornings of the 21st and 22nd. 
By the end of August Venus is rising a 
bit more than an hour before the Sun. 

Mars starts July setting a little more than 
two hours after the Sun. But the planet 
is shining at only magnitude +1.8 — as 
dim as it can get. Look for it low in the 
west-northwest sky, beginning about an 
hour after sunset. Don't confuse it with 
Saturn, which is about three times 
brighter, but well below and to the right 



of Mars. Ifyou are blessed with very clear 
weather on the evenings of the 21st and 
22nd, look for Mars hovering less than 
a degree above and to the right of Reg- 
ulus, the brightest star in the constella- 
tion Leo, the lion. You'll probably need 
binoculars to pick them up, but if you 
do, you'll likely be impressed by the col- 
or contrast between yellow-orange 
Mars and bluish Regulus. 

This summer Jupiter is the most favor- 
ably placed planet to view. At the start 
of July it's shining brightly at magni- 
tude —2.3 in the south-southwest sky 
and doesn't set until around 2 A.M. lo- 
cal daylight time. At the start of August 
it's in the southwest at sunset and sets 
around midnight. By the end of Au- 
gust it's setting about two and a half 
hours after sunset. Jupiter's retrograde, 
or westward, motion among the stars 
ends on July 6; thereafter, it starts shift- 
ing back to the east and will approach 
the star Zubenelgenubi, also known as 
Alpha Librae in the constellation Libra, 
the scales, for the rest of July and Au- 
gust. By August 1 , the star and the plan- 
et are within five degrees of each oth- 
er, but the two bodies continue closing 
in to a separation of less than two de- 
grees by month's end. Look for Jupiter 
at dusk on the 29th, hovering above 
and to the right of a fat crescent Moon. 

Saturn, for the first couple of weeks of 
July, can be spied low in the west-north- 
west sky for about an hour after sunset. 
Ultimately, however, the planet disap- 
pears into the glow of evening twilight. 
Use Mercury and brilliant Venus to 
guide you to Saturn as it emerges into 
the morning sky in late August. On the 
20th, Saturn approaches to within 
slightly more than one degree of 
Mercury; both planets lie below and to 
the left of Venus. A sliver of a crescent 
Moon passes well above and to the left 
of Saturn on the morning of the 22nd. 
The next morning, Mercury and Venus 
form the end points of a diagonal line 
about eight degrees long against the sky, 
while Saturn lies almost exactly halfway 
in between. By the 26th, Saturn lies a 



half degree below and slightly to the left 
of Venus. By the following morning it 
is a half degree above and slightly to the 
right of Venus. But compared with that 
dazzling morning "star," Saturn appears 
only a forty-eighth as bright. 

The Moon in July waxes to first quarter 
on the 3rd at 12:37 P.M., and becomes 
full on the 10th at 11:02 p.m. It wanes 
to last quarter on the 17th at 3:12 P.M. 
and to new on the 25th at 12:31 A.M. 
On the 20th a waning crescent Moon, 
24 percent illuminated, occults, or pass- 
es in front of, the Pleiades star cluster as 
seen from eastern North America. That 
early-morning event takes place about 
a quarter of the way up in the eastern 
sky. In some ways it will be the reverse 
of the occultation of April 1 . This time, 
between roughly 3 and 5 A.M. eastern 
daylight time, stars disappear along the 
Moon's sunlit crescent and reappear 
from behind the dim earthlit edge. 

In August the Moon waxes to first 
quarter on the 2nd at 4:46 A.M., and to 
full on the 9th at 6:54 A.M. The Moon 
wanes to last quarter on the 1 5th at 9:5 1 
P.M., and returns to new on the 23rd at 
3:10 P.M. The Moon then comes back 
to first quarter for the second time in 
August on the 31st at 6:56 p.m. 

Earth reaches aphelion, its farthest point 
from the Sun, on July 3 at 7 P.M.; the two 
bodies will be 94,507,915 miles apart. 

The Perseids are one of the most active 
and reliable meteor displays of the year. 
Unfortunately, the bright light of a 
waning gibbous Moon — four days past 
full — will largely spoil this year's Per- 
seid show. The show peaks on the 
morning of August 13. You might want 
to watch anyway, because even in the 
brightest moonlight a brilliant Perseid 
fireball occasionally blazes across the 
sky. The best time to watch is between 
midnight and dawn. Lie down and gaze 
at the part of the sky directly away from 
the Moon. 

Unless othemnsc noted, all rimes are given 
in eastern daylight time. 



58 



NATURAL HISTORY July/August 2006 



1 



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Egypt's Nile Delta 
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Backcountry 
Archaeology: 
Comb Ridge 

May 6-12, 2007 

Chaco Canyon: 
Two Perspectives 

May 20-26, 2007 

Northern Chaco 
Seminar 

May 27-June 2, 2007 



SUMMER 



Prehistory to Present: 
French Caves, Castles, 
& Canvases 

June 9-19, 2007 

Archaeology of 
Bandelier and 
the Pajarito Plateau 

June 10-1 6, 2007 

Clay Workshop with 
Michael Kanteena 

July 1-7, 2007 

Northwest Coast Art 
& Cultures of 
Vancouver Island 

August 1-11. 2007 

1006 Tours Available 

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ARCHAEOLOGICAL CENTER 
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800.422.8975 / www.crowcanyon.org 




At the Museum 

American Museum o Natural History 



www.amnh.org 



Yellowstone to Yukon 

Opens July 15, 2006 



Yellowstone to Yukon, an enthralling 
exhibition of over 40 full-color 
photographs, opens July 15, 

2006, in the Ameri- 
can Museum of Nat- 
ural History's IMAX 
Corridor on the first 
floor. On view 
through January 15, 

2007, the exhibition 
showcases the diverse 
flora, fauna, and geol- 
ogy of the North 
American West — 
from Wyoming to the 
Yukon Territory — 
with lush images of 

breathtaking landscapes and spectacular 
wildlife. These photographs take viewers 
on an unrestricted journey through the 
wilderness as well as the rapidly develop- 
ing areas of the Yellowstone to Yukon 
region to explore an ambitious corridor 
initiative that connects habitats so wide- 
ranging animals can travel unimpeded 



Moose in burnt boreal forest 



by human structures and development. 

The photographs on display illustrate 
some challenges and current solutions for 
reconciling human 
and economic devel- 
opment with wildlife 
conservation. The 
exhibition depicts, 
for example, wild 
animals crossing 
roadways, which is 
hazardous to both 
the animals and 
drivers. Juxtaposed 
against these scenes 
of humans' interac- 
tion with the wild are 
images of animals using "wildlife over- 
passes" constructed for the animals' safe 
passage, demonstrating marked headway 
in conservation efforts in the region. 

Eleanor Sterling, Director of the 
Museum's Center for Biodiversity and 
Conservation, curates the installation of 
Yellowstone to Yukon at the Museum. 





Herd of pronghorn antelope 

Some of the photographs in this exhi- 
bition are taken from the book Yellow- 
stone to Yukon: Freedom to Roam, which 
is available in the Museum Shop. 

This exhibition was developed by the American Museum 
of Natural History's Center for Biodiversity and Conser- 
vation in concert with the Yellowstone to Yukon 
Conservation Initiative and the Wilburforce Foundation 
and is made possible by their support. Additional gener- 
ous support provided by the Woodcock Foundation. 



LIZARDS & SNAKES: ALIVE! 

July 1, 2006-January 7, 2007 




This new exhibition at the American Museum of 
Natural History will captivate children and adults 
alike with more than 60 live lizards and snakes. Visi- 
tors will learn how lizards and snakes are part of the 
same group of animals; about the way these diverse 
creatures move, from leaping to slithering to running 
on water; the way they capture food, from "snaking" 
out their projectile tongues to unhinging their gaping 
jaws; their effective methods of camouflage; and 
other sometimes surprising adaptations. 



Veiled chameleon 



PEOPLE ATTHEAMNH 



Michael Cosaboom 

Manager of Interactive Exhibits 
Department of Exhibitions 




Michael Cosaboom, whose team 
develops computer-based 
media for special exhibitions, says 
that of all the projects he's worked 
on in his nearly five years at the 
Museum, the new exhibition Lizards 
flf Snakes: Alive! is his favorite. 

"This is the first show where I've 
been involved from start to finish on 
not just the technical side but content 
as well. The curators have been amaz- 
ing, giving really specific feedback 
about what they want." 

Michael and his team collaborated 
with the curators to create an interac- 
tive, educational video game of a 
snake on the hunt that ends with a 
high-definition depiction of the 
snake's skull while it swallows its prey. 

"People will see a desert environ- 
ment from the point of view of a 
snake, see how it moves when it 
strikes, and what happens when it 
swallows something. We were able to 
produce this with scientific accuracy — 
and it's fun." 

After studying anthropology at the 
University of Michigan, the Wilming- 
ton, Delaware, native spent several 
years doing social work and youth 
work when he got "excited by how 
young people reacted to computers." 
He went on to hone his skills in com- 
puter programming and design at 
NYU's Interactive Telecommunica- 
tions Program. 

Off the job, Michael spends as 
much time as he can with his five-year- 
old son, Wilder, who is as excited 
about his father's workplace as 
Michael is. "Wilder loves coming to 
the Museum. In his imagination, he 
has his own museum that he runs." 



Last Chance! DARWIN 

Closes August 20 




Galapagos tortoise 



This tortoise is just one of the live 
animals in Darwin that has made 
the exhibition so popular that it 
was extended three months past 
its original closing date. But now 
your last chance to see this stun- 
ning exhibition is approaching: 
Darwin closes August 20. Don't 
miss live animals, original manu- 
scripts, specimens collected by 
the great naturalist himself, a 
meticulous re-creation of his 
study, and much more. 



Starry Nights Live Jazz 



Rose Center for Earth 
and Space 

Friday, June 2 

6:00 and 7:30 p.m. 

Jeremy Pelt & Creation 




Friday, August 4 

6:00 and 7.J0 p.m. 

Visit www.amnh.org for lineup. 

The 7:30 p.m. set will be broadcast live on 
WBCOJazz 88.3 FM. 



Starry Nights is made possible, in part, 
by Fidelity Investments. 



Starry Nights, the enormously popular series of live jazz performances under the sphere 
of the Hayden Planetarium, takes place on the first Friday of every month. The series fea- 
tures renowned jazz musicians performing in one of the most spectacular settings in New 
York. Visitors to Starry Nights can enjoy mouthwatering tapas along with wine and other 
beverages during performances. 



Space Shuttle Launch LIVE 

Visit AMNH Space Events Web page for details 



July marks the return of NASA's Space Shuttle fleet to 
service after more than three years of engineering 
analysis and redesign. Join scientists and space educa- 
tors from AMNH to watch the launch of Space Shuttle 
Discovery live in the Cullman Hall of the Universe in 
the Rose Center for Earth and Space. Launch is cur- 
rently scheduled for no earlier than July 1. Please visit 
www.amnh.org/space-events to get an up-to-the- 
minute schedule of events as the launch approaches. 




The contents of these paces are provided to Natural History by the American Museum of Natural Histor' 



Museum Events 

American Museum 5 Natural History \jC ) 



www.amnh.org 



EXHIBITIONS 

LAST CHANCE! Darwin 

Through August 20, 2006 
Featuring live animals, actual 
fossil specimens collected by 
Charles Darwin, and manu- 
scripts, this magnificent exhibi- 
tion offers visitors a comprehen- 
sive, engaging exploration of the 
life and times of Darwin, whose 
discoveries launched modern 
biological science. 

The American Museum of Natural 
History gratefully acknowledges 
The Howard Phipps Foundation 

for its leadership support. 
Significant support for Darwin 
has also been provided by 
Chris and Sharon Davis, 
Bill and Leslie Miller, 
the Austin Hearst Foundation, 
Jack and Susan Rudin, 
and Rosalind P. Walter. 
Additional funding provided by 
the Carnegie Corporation of New York, 
Dr. Linda K. Jacobs, and the 
New York Community Trust- 
Wallace Special Projects Fund. 

Darwin is organized by the American 
Museum of Natural History, New York 
(www.amnh.org), in collaboration with the 
Museum of Science, Boston; The Field 
Museum, Chicago; the Royal Ontario 
Museum, Toronto, Canada; and the Nat- 
ural History Museum, London, England. 



els, videos, and interactive sta- guest from the United Nations, 
tions will complement the more 
than 60 live animals represent- 




Blue-footed boobies 

Lizards <£ Snakes: Alive! 

Opens July 1, 2006 
Live lizards and snakes are the 
center of attention in this engag- 
ing exhibition that will explore 
these creatures' remarkable 
adaptations, including projectile 
tongues, deadly venom, amaz- 
ing camouflage, and sometimes 
surprising modes of movement. 
Fossil specimens, life-size mod- 



mg 27 species. 

Lizards, t- Snakes: Alive 1 , is made 
possible, in part, by grants from 
The Dyson Foundation and the Amy 
and Larry Robbins Foundation. 

Lizards & Snakes: Alive! is organized by the 
American Museum of Natural History, 
New York (www.amnh.org), in collabora- 
tion with the Fernbank Museum of Nat- 
ural History, Atlanta, and the San Diego 
Natural History Museum, with apprecia- 
tion to Clyde Peeling's Reptiland. 




Ding Shunchang 

EXTENDED! Voices from 
South of the Clouds 

Through January 2, 2007 
China's Yunnan Province is re- 
vealed through the eyes of the in- 
digenous people, who use pho- 
tography to chronicle their cul- 
ture, environment, and daily life. 

The exhibition is made possible by a gener- 
ous grant from Eastman Kodak Company. 
The presentation of this exhibition at the 
American Museum of Natural History is 
made possible by the generosity of the 
Arthur Ross Foundation. 

Vital Variety 

Ongoing 

Beautiful close-up photo- 
graphs highlight the diversity 
of invertebrates. 

GLOBAL WEEKENDS 

Indigenous Peoples' Day 

Saturday, 8/12, 1:00-5:00 p.m. 
The afternoon includes Native 
American cultural perfor- 
mances, films, and a special 



Global Weekends are made possible, in 
part, by The Coca-Cola Company, the 
City of New York, and the New York City 
Council. Additional support has been 
provided by the May and Samuel Rudin 
Family Foundation, Inc., the 
Tolan Family, and the family of 
Frederick H. Leonhardt. 



LECTURES 

Adventures in the 
Global Kitchen: Rum 

Tuesday, 7/11, 7:00 p.m. 
Explore the rise, fall, and re- 
turn of rum. This program 
includes tastings of rum- I 
based cocktails. 



Join the co-curators of the exhi- 
bition Lizards a[ Snakes: Alive! to 
learn what inspired them to be- 
come scientists. 

LIZARD SUNDAYS 
$25 each; $65 for all three 
(of the same age group) 

Lizard Locomotion 

Sunday, 7/16, 11:00 a.m- 
12:30 p.m. (Ages 4-6, each child 
with one adult) and 1:30- 
y.oop.m. (Ages 7-9) 



Lessons of the Gecko 

Tuesday, 7/18, 7:00 p.m. 
The millions of tiny hairs on a 
gecko's feet are helping scien- 
tists develop new adhesives. 
Discuss the implications of this 
research and its potential uses. 

FAMILY AND CHIL- 
DREN'S PROGRAMS 
Wild, Wild World: 
Lizards & Snakes 

Saturday, 7/1, 12:00 noon- 
1:00 p.m. and 2:00-3:00 p.m. 
Live lizards and snakes, intro- 
duced by "Lizard Man" Clyde 
Peeling. 

Wild. Wild World is made possible, in part, 
by Mortimer B. Zuckerman. 





Clyde Peeling with alligator 

Free Event! How I 
Became a Herpetologist 

Sunday, 7/9, 12:00 noon- 
1:15 p.m. 



Gecko adhering to glass 



Lizards Who Lunch 

Sunday, 7/2}, 11:00 a.m- 
12:30 p.m. (Ages 4-6, each child 
with one adult) and 1:30- 
y.oop.m. (Ages 7-9 J 

Lizard Lore 

Sunday, 7/30, 11:00 a.m- 
12:30 p.m. (Ages 4-6, each child 
with one adult) and 1:30- 
y.oop.m. (Ages 7-g) 

AMNH ADVENTURES: 
SUMMER CAMPS 
Three- and five-day sessions en- 
gage children in fun investiga- 
tions of different scientific fields: 

• Monkey Business: 
Primatology 

• Leapin' Lizards 

• Meet the Beetles: 
Darwin Adventures 

• Destination Space: 
Astrophysics 

• Robotics 

For details, visit www.amnh.org 
or call 212-769-5758. 



HAYDEN PLANETARIUM 
PROGRAMS 

TUESDAYS IN THE DOME 
Virtual Universe 
Stars of Many Colors, Includ- 
ing Red, White, and Blue 

Tuesday, 7/4, 6:30-7:30 p.m. 
The Grand Tour 

Tuesday, 8/1, 6:30-7:30 p.m. 

This Just In... 
July's Hot Topics 

Tuesday, 7/18, 6:30-7:30 p.m. 
August's Hot Topics 

Tuesday, 8/35, 6:30-7:30 p.m. 

Celestial Highlights 
Midsummer Skies 

Tuesday, 7/25, 6:30-7:30 p.m. 
The Triangle and 
the Celestial Sea 

Tuesday, 8/29, 6:30-7:30 p.m. 




Kids show off their 
summer camp projects. 



HAYDEN PLANETARIUM 
SHOWS 

Cosmic Collisions 
Journey into deep space — well 
beyond the calm face of the 
night sky — to explore cosmic 
collisions, hypersonic impacts 
that drive the dynamic forma- 
tion of our universe. Narrated 
by Robert Redford. 

Cosmic Collisions was developed in col- 
laboration with the Denver Museum of 
Nature & Science; GOTO, Inc., Tokyo, 
Japan; and the Shanghai Science and 
Technology Museum. Made possible 
through the generous support of CIT. 
Cosmic Collisions was created by the 
American Museum of Natural History 
with the major support and partnership 
of the National Aeronautics and Space 
Administration's Science Mission Direc- 
torate, Heliophysics Division. 

SonicVision 

Fridays and Saturdays, 
7:30 and 8:30 p.m. 
Hypnotic visuals and rhythms 
take viewers on a ride through 
fantastical dreamspace. 

SonicVision is made possible by generous 
sponsorship and technology support from 
Sun Microsystems, Inc. 

LARGE-FORMAT FILMS 

LeFrak I MAX Theater 
journey into Amazing Caves 
Visit www.amnh.org for 
showtimes. 

IMAX films at the Museum are made 
possible by Con Edison. 




The Museum's spectacular new Space Show 
INFORMATION 

Call 212-769-5100 or visit www.amnh.org. 

TICKETS AND REGISTRATION 

Call 212-769-5200, Monday-Friday, 9:00 a.m. -5:00 p.m., 
or visit www.amnh.org. A service charge may apply. 
All programs are subject to change. 

AMNH eNotes delivers the latest information on Museum 
programs and events to you monthly via email. Visit 
www.amnh.org to sign up today! 



Become a Member of the 
American Museum of Natural History 

As a Museum Member, you will be among the first to 
embark on new journeys to explore the natural world 
and the cultures of humanity. You'll enjoy: 



Unlimited free general 
admission to the Museum 
and special exhibitions, 
and discounts on Space 
Shows and IMAX films 

Discounts in the Museum 
Shops and restaurants and 
on program tickets 



Free subscription 
to Natural History 
magazine and to Rotunda, 
our newsletter 

Invitations to Members- 
only special events, 
parties, and exhibition 
previews 



For further information, call 212-769-5606 
or visit www.amnh.org/join. 




From our newest exhibition, Lizards & Snakes: Alive! this adorable 
veiled chameleon comes perched on a Museum mug or preying on a fly 
on this canvas tote. 



Call our Personal 
Shopper at 
1-800-671-7035 
or shop at 
www.amnh.org. 




The contents of these paces are provided to Natural History by the American Museum of Natural History. 



EN DPAPER 



Grumpy, fuzzy, scholarly 
type was beside himself. 
Halfway up the ten-foot- 
high rock wall he'd run out of toe- 
holds, and he clung desperately to 
the tiny fingerholds above him. 
The wall was made of layers of 
shale, inch-thick ledges protruding 
irregularly from the mesa, and he 
couldn't find a higher one to stand 
on. The distinguished professor of 
physiology and evolution was stuck. 

I pushed on his bottom. Someone 
pulled him from above. Finally he 
scrabbled onto the top of the mesa 
and fell, prostrate, on the flat, hard, 
dusty surface. After a minute he rolled 
over, tears of exertion still in his eyes. 

About ten people toiled atop the 
mesa, all paleontologists. We were 
prospecting for fossils at one of those 
small, scarcely known paleontologica 
sites that abound in the western 
United States. This one — Bear 
Gulch — is situated on a cattle ranch 
in central Montana. The leader of 
our team had written profusely about 
shark fossils of the Mississip- 
pian period, 300 million 
years ago. Back then, Bear 
Gulch was an inlet of what 
was to become the Pacific 
Ocean. Warm and shallow, it 
was a perfect pupping ground 
for sharks. Occasionally a ju- 
venile shark would die there 
and sink to the seafloor, soon to be 
buried in the soft, oxygen-poor bot- 
tom mud. 

Those rich, shallow waters teemed 
with plankton. They, too, sank to the 
bottom when they died, forming a 
layer on top of the mud. Bacteria 
dined on them, oxidizing the proto- 
plasm of the dead plankton layer. Re- 
producing every twenty minutes, the 
bacterial masses used up virtually 
every molecule of available oxygen. In 
this oxygen-starved burial place, the 
shark carcasses remained intact until 
the mud, gradually and under im- 
mense pressure, became stone — shale. 
Along with their encasement of mud, 
the tiny sharks turned to stone. Three 
hundred million years later, a team of 



Hard Labor 
at Bear Gulch 

By Eugene H. Kaplan 




Layers of petrified sediment 
in Bear Gulch, Montana 
(above), hold some of the 
best-preserved marine fossils 
in the world, including this 
300-million-year-old horse- 
shoe crab (left). 



toiling paleontologists broke into their 
tombs and let the sunshine in. 

The graduate students punctuated 
their jolly conversations with 
grunts of exertion as they pried up 
layers of the petrified mud. The tech- 
nique was to slip the sharp end of a 
five-foot steel spike into the junction 
between two layers and pound at the 
seam until the layers loosened. Then 
they would wedge the spike into the 
shale and lever it upward, breaking off 
a slab a yard or so wide. When the 
slab was turned over, it would usually 
reveal . . . nothing. But occasionally a 
more professional-sounding grunt 
drew everyone's attention to a digger 



who had found, in all its perfec- 
tion, the imprint of a tiny shark, 
its scales defined and its eyes 
turned upward in a stony stare. 

My fuzzy, distinguished colleague 
and I also grunted frequently while 
we worked — not to prove we were 
just as professional as the grad stu- 
dents, but because our aging bodies 
made it hard to lift the heavy layers 
of rock. Sweating under a glaring sun, 
we finally learned how to use mechan- 
ical advantage, wedging up pieces of 
shale with the best of them. Neverthe- 
less, the flat undersides of slab after la- 
borious slab had nothing to show us. 

Finally the two of us came upon a 
curled object — shaped like a sinuous 
peanut — embedded in the shale. Ex- 
cited, we dragged the two-foot-wide 
chunk of rock to the head honcho, 
who stared at it intently and informed 
us it was a coprolite. We looked at him 
quizzically "It's petrified fish feces," he 
explained. All that labor and exhaus- 
tion only to find ancient fish poop! 

The team worked until dark, our 
labors illuminated by a magnificent, lu- 
minous sunset. After dinner that 
evening the buttes and mesas rang with 
laughter as we were presented with our 
hard-won trophy — the coprolite — 
which, to this day, lies in state in the 
glass-fronted case that doubles as my 
class museum. Thoroughly tired, and 
mildly amused by our moment of tri- 
umph, I crawled into my tent, pushing 
at its nylon floor to carve out a flat 
space amid the ubiquitous cow flops. A 
pat of "prairie pancake" was my pillow. 

The next day, another grunt 
brought us running. Although the 
fossil turned out to be of little interest 
to this group of ancient-shark special- 
ists, to me it was a real treasure. I let 
loose a holler. There on the under- 
side of the rock was a small, perfect, 
300-million-year-old replica of a 
modern-day horseshoe crab. 

Eugene H. Kapl.4n is Axinn Distinguished 
Professor of Conservation and Ecology at Hqfstra 
University, in Hempstead, Sen- York. This story 
is adapted from his book Sensuous Seas: Tiles 
of a Marine Biologist, which will be pub- 
lished in August by Princeton L J uivcrsity Press. 



NATURAL HISTORY July/August 2006 



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