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Full text of "The small mammals of Colorado"

WARREN 
The Small Mammals of Colorado 




QL 

719 

C6 

W25 



The 

Small Mammals of Colorado 



By 

EDWARD ROYAL WARREN, S. B. 




ILLUSTRATED 



Published by 
THE COLORADO MOUNTAIN CLUB 

June, 1921 

George H. Harvey, Jr President 

3120 West Twenty-third Avenue, Denver. 

George C. Barnard Vice President 

615 Seventeenth Street, Denver. 

Katharine Bruderlin Secretary 

1276 Emerson Street, Denver. 

William L. Myatt Treasurer 

3053 West Twenty-ninth Avenue, Denver. 

Publication No. 7 Price: 25 Cents 



\twaan asun 

L The 

Small Mammals of Colorado^ 



By 

EDWARD ROYAL WARREN, S. B. 




ILLUSTRATED 



Publii-hrd by 

THE COLORADO MOUNTAIN CLUB 

June, 1921 

George H. Harvey, Jr President 

8120 West Twenty-third Avenue, Denver. 

George C. Barnard Vice President 

01") Seventeenth Street, Denver. 

Katharine Bruderlin Secretary 

127(5 Emerson Street, Denver. 

William L. Myatt Treasurer 

3053 West Twenty-ninth Avenue, Denver. 

Publication No. 7 Price: 25 Cents 



COPYRIGHT, 1921. 

BY THE 
COLORADO MOUNTAIN CLUB. 



INTROD 



THIS bulletin on the small mammals of Colorado omits all mention of 
the tree squirrels, ground squirrels, chipmunks, and gophers, which 
were excellently treated by Mr. Robert Rockwell in his bulletin on those 
animals. The present paper aims to give some mention of our smaller 
mammals, though it has been a little difficult at times to tell where to 
draw the line, and what to include and what to omit. Many of these ani- 
mals are but little known to the casual observer, largely because of the 
nocturnal habits of the majority of the species, and the retiring habits of 
others. When one becomes acquainted with them and their ways he finds 
them very interesting, and their life histories well worth studying. In 
fact there is still much to be learned about many of them. 

Since the writer's "The Mammals of Colorado" was published, some 
ten years ago, a number of the genera of North American mammals have 
been studied by specialists, with the result that some species and sub- 
species have been added to and others dropped from our local list, and 
some of the scientific names have been changed. While not making the 
latter especially prominent in the text, they have invariably been given, 
for they are a more positive identification of the species than any English 
or vernacular names. No detailed descriptions of any of the species are 
included, only a general idea of the color and size is given. The total 
length is from the end of the nose to the end of the tail, measured in a 
straight line when the animal is stretched out, and the tail is measured 
from the root to the tip. 

I have omitted all mention of the bats, although a considerable number 
of species is found in the State. These belong to so many different genera 
that a general description of the animals would be very unsatisfactory, and 
a detailed account is somewhat beyond the scope of this paper. 

For interesting and authoritative accounts of the habits of many of 
our small mammals I would refer my readers to "The Wild Animals of 
North America," by E. W. Nelson, Chief of the U. S. Biological Survey, 
published by the National Geographic Society. Mr. Nelson's opportunities 
of observing the habits of many of our species have been remarkable, and 
he has made much use of the work of other naturalists. 

In giving scientific names, when the name of a genus is repeated it is 
not given in full but abbreviated to the initial letter; likewise in the case 
of repetition of specific names. 

Unless otherwise mentioned, the illustrations are from my own photo- 
graphs. Nos. 1, 2, 3, 4, 6, 7, 8, 10, 11, 13, 14, 15, 16, 18 and 20 were 
originally published in the "Mammals of Colorado" and are printed from 
the cuts used in that book. For several of the illustrations which have not 
hitherto been published, I wish to acknowledge my indebtedness to Mr. 
Charles Mace, Mr. Clark Blickensderfer, Mr. Albert Haanstad, and the 
Colorado Agricultural College through Mr. W. L. Burnett. 

The pictures will doubtless be of as much use as the text In showing 
what the animals are like. E. R. W. 



3 



The Small Mammals of Colorado 



MOLES AND SHREWS. 

Our single species of mole is confined to the northeastern portion of 
Colorado, indeed the only record of which I have knowledge is from Wray. 
This species is the Northern Plains Mole, Scalopus aquaticus caryi. In 
"The Mammals of Colorado" it is called the Large-nosed or Western 
Silvery Mole. Both moles and shrews belong to the order Insectivora, the 
members of which depend largely upon insects and similar forms of ani- 
mal life for their subsistence. 

Of exclusively underground habits, moles are rarely seen on the sur- 
face of the ground, though they make their presence known by the mounds 
of earth which they throw up from their tunnels. These tunnels are made 
in their search for food, which consists of earthworms and grubs. The 
forelegs are short, with wide, naked hands, the palms being turned out- 
ward, and forming splendid instruments for digging. The velvety fur 
almost hides the eye. This fur is brown, with grayish shades, lighter 
below, appearing dull or bright and silvery according as the light strikes 
the hair. Moleskins are used as fur, being very soft and warm, though it 
takes many to make a garment. 

The small animals known as Shrews are often confused with mice, to 
which they are not at all nearly related, belonging, as previously stated, 
to the Insectivora, while mice are rodents, or gnawers. Four of our Colo- 
rado species are tiny brown animals about four inches long, of which the 
tail comprises somewhat less than half. They live about the damp meadows 
in the mountains, along the streams, and also among the dead logs and 
underbrush in the timber, and range to timberline, and even to the summit 
of Pikes Peak. They make much use of meadow mice runways, and are 
often captured in traps set in such places. Voracious little animals, with 
sharp teeth and savage dispositions, they have no hesitation in attacking 
prey as large as themselves. If two are confined together one usually kills 
and eats the other, and they are said to occasionally kill mice.. The eyes 




No. 1. Dusky Shrew, Sorex obsenruH; photographed from a dead specimen. 
5 



are very small, and doubtless the sight is poor and the animal much de- 
pendent on the flexible, sensitive snout to aid it in its activities. Shrews 
are about both by day and by night. 

The four species of small shrews in Colorado are the Masked Shrew, 
Sorex personatus, Dobson's Shrew, Sorex vagrans dobsonl, Dusky Shrew, 
Sorex obscurus, and the Dwarf Shrew, Sorex tenellus nanus. 

Besides these small shrews there is a larger species, the Water Shrew, 
Neosorox navigator, about the size of our common deer mice. It is a hand- 
some little animal, with close, soft, glossy fur of a plumbeous color, mixed 
with hoary above and silvery white below. It is found along the moun- 
tain streams, more especially at the higher altitudes, ranging from 7,000 
to over 10,000 feet. Its food habits are much the same as those of the 
small species. 

RING-TAIL. 

The Ring-Tail, known to the Mexicans as "Cacomixtle", and also 
called "Civet Cat", a name to which it has exactly as much right as the 
Spotted Skunk has which is none at all is an inhabitant of the lower 
portions of southwestern Colorado, and has been taken as high as 6,800 
feet, though its usual range is no doubt much lower than that. It is a 
pretty little animal, about 29 inches long, the tail being about half of the 
total length. Buff mixed with black is the body color, and the tail is ringed 
alternately with black and white and has a white tip. 

Really closely allied to the raccoon, it is like that animal in being a 
somewhat indiscriminate feeder, eating jats, mice, and other small mam- 
mals, birds, insects, and at times fruits and berries. It is strictly nocturnal. 
Miners and others sometimes make pets of these animals, and find them 
very interesting. The scientific name is Bassariscus astutus. 

MARTEN. 

The Pine or Rocky Mountain Marten, Martes caurina origenes, is con- 
fined to the heavy spruce timber of the highest mountains and is rather 
rare, being irregularly distributed through its range. It leads to a great 
extent an arboreal life, being as much at home in a tree as a squirrel. It 
is a handsome animal with its brown coat and fine soft fur, which always 
brings a good price. The throat is yellow and orange from the chin to 
between the forelegs, this varying much in different individuals. Like 
other weasels, it lives on rats, mice, squirrels and birds. The young are 
born early in spring, and are about six to the litter, the nests being in 
hollow trees, under fallen timber, and in holes in the ground. 

WOLVERENE. 

Wolverenes (Gulo luscus) are very rare animals in Colorado, and are 
confined to the higher portions of the timber in the mountains. It is 
seldom one hears of the animal, and it is often found on enquiring that 
it is unknown in the locality. It is a powerfully built creature, about forty 
inches long, of which the tail comprises ten inches. The stout, heavy-set 
body and short legs with long, sharp claws make an effective combination 
for the destructive work of which the animal is capable, and with which it 
is credited in the northern regions, such as destroying traps, and caches 
of food and supplies. The color is dark brown above, and lighter along 
the sides and beneath. The fur has considerable value. The young are 
born about June and are from one to three in a litter. 

WEASELS. 

For real bloodthirstiness the Weasels probably come as near deserving 
the palm as any group of mammals. Certainly they are wicked little 
beasts, and courageous too, for they will put up a fight against enemies 

6 



many times their size. The Marten and Wolverene are also weasels, 
though of larger size than the species to which the term is restricted in 
popular parlance. Of the four species of weasel found in Colorado, three 
have a white winter coat and a brown summer coat, the fourth, the Black- 
footed Ferret (Mustela nigripes), keeps its yellowish brown coat- the year 
round. The first three species are the Long-tailed Weasel, Mustela longi- 
cauda, Mountain Weasel, Mustela arizonensis, and the Dwarf Weasel, 
Mustela streatori leptus, the first-named being the largest, and an inhabi- 
tant of the plains, while the other two live in the foothills and mountains. 
While the Ferret is 19 to 20 inches long the Dwarf Weasel is about 9^ 
inches in length. 

The Ferret was discovered by Audubon and described by him, ana 
then no additional specimens were seen by naturalists for so many years 
that it came to be regarded almost as a myth. It is, however, pretty well 
distributed over the plains region, though nowhere common, and in Colo- 
rado occurs in South Park, and possibly in our other high parks. It is 
addicted to living about the prairie dog towns, where it preys on the in- 
habitants. 

Weasels live on mice, chipmunks, ground and tree squirrels, and birds 
when they can catch them. Once when I was riding up a steep mountain 
trail a chipmunk came running down the hill before me and turned up 
the trail, squealing all the time as if in mortal terror, for which there 
seemed ample reason when a moment later a weasel came along, nose to 
the ground, following the chipmunk's trail. It stopped a second or two 
to look at me, then went on, and I doubt not that soon a chipmunk came 
to an untimely end. 

Weasels have rather large families, six or eight in a litter, once a 
year, and no doubt the parents have to rustle hard to provide food for the 
hungry mouths. They destroy many mice, and no doubt as a rule they 
are beneficial rather than otherwise. 

All weasels are provided with scent bags near the rectum and, though 
small, if one is cut open the odor is very penetrating and almost over- 
powering. 

MINK. 

Minks are weasels leading a semiaquatic life, and are somewhat larger 
than the Black-footed Ferret, being about two feet long. Their brown fur 
has always been in demand, and brings a good price; it is not only a 
handsome fur, but a very durable one, wearing well for many years. Mink 
are probably found along all the streams which contain food for them, 
both on the plains and in the mountains. Fish are eaten, as well as mice, 
squirrels and birds. They are not too particular, so long as it is flesh 
and they capture it themselves, or if they can steal it from the captor, as 
they will fish if left where it is accessible. Occasionally a Mink makes 
a raid on a poultry yard with destructive results. The home is in a hole 
near the water, and doubtless muskrat burrows are often occupied. 

SKUNKS. 

These malodorous animals are represented in Colorado by species be- 
longing to two different genera, the large skunks with white stripes on 
the back, belonging to the genus Mephitis, and the smaller spotted skunks 
belonging to the genus Spilogale. There are two species of the large 
skunks in Colorado, the Northern Plains Skunk (Mephitis hudsonica), and 
the Long-tailed Texas Skunk (Mephitis mesomelas varians). The latter is 
probably the most widely distributed of the two, but skunks are found all 
over the state, going to at least 10,000 feet, at which altitude in Gunnison 
county I once had the pleasure of inhaling the perfume of one in March 

7 



when the snow was five feet deep, but did not see the animal itself, and 
knew not what stirred it up. 

These animals are not at all particular as to their diet. They eat 




No. 2. Long-tailed Texas Skunk, Mephitis mes 



mice and any other small animals which come their way. Ground-nesting 
birds and their eggs suffer, while grubs and grasshoppers are eaten in 
large numbers. I think at times they must largely subsist on these latter 
insects. Take it all around, skunks are really useful. They are prolific 
breeders, six or eight young in a litter. 

Recently, when furs were at the top prices, the best black skunk skins 
were quoted at figures once applicable to far more valuable furs. It is a 
really good and durable fur, however, wearing very well indeed. 

SPOTTED SKUNKS. 

These pretty little skunks furnish the fur known to the trade as 
"Civet," a name properly belonging to a quite different animal. There are 
four species of these skunks found in Colorado, the Prairie Spotted Skunk, 
Spilogale iiiterrupta, Arizona Spotted Skunk, Spilogale arizonae, Rocky 
Mountain Spotted Skunk, Spilogale temiis, and the Great Basin Spotted 
Skunk, Spilogale gracilis saxn tills. These skunks do not range so high 
in the mountains as their larger relatives, 8,000 feet probably being their 
limit in altitude. Below this they appear to be pretty generally distributed 
over the state. While there is a general similarity in the habits^ of both 
groups, the small ones are more lightly built and active and even to some 
extent climb into trees and bushes. In many parts of the West they are 
called "Hydrophobia Skunks" or "Phoby Cats". There is a somewhat uni- 
versal impression that their bite always causes hydrophobia and is invari- 
ably fatal. A. H. Howell of the U. S. Biological Survey says in this con- 
nection: "While there are a few authentic cases of skunk bite having 
resulted fatally there are also many instances in which it has produced no 



ill effects whatever. The recorded cases of skunk rabies are nearly all 
from the plains region of the west (Kansas, Texas, and Arizona) ana 
relate more to Mephitis than to Spilogale. The most plausible explanation 
of these facts seems to be that at certain periods rabies may become locally 
epidemic among dogs and wolves, and by them be communicated to 
skunks." 

I recall a somewhat amusing incident in this connection. I was in 
western Gunnison county on a surveying expedition, having a couple of 
men along. A deer had been killed after arriving at camp and was hang- 
ing up close to our beds. I slept with one of the men. Toward daylight 
I was awakened by his making a sudden movement and exclaiming very 
emphatically "Get out of here". I said, "What's the matter, Henry?" 
Henry looked rather foolish, and said, "Oh, nothing." Next morning he 
told me that a skunk had been poking about after scraps of meat, and he 
was afraid it might bite him, so had thrown his hat at it. Fortunately 
nothing disagreeable had happened, but I suggested he would better not 
be so impulsive next time. 

Neither of the skunks has many enemies besides man, though the 
Great Horned Owl does kill and eat them, thereby rendering its plumage 
distinctly odoriferous. 

The stripes and spots on the small species make a decidedly effective 
fur and it is in considerable demand. 

HOG-XOSED OR WHITE-BACKED SKUNK. 

While the manuscript of this bulletin was in course of preparation 
Mr. C. E. Aiken of Colorado Springs called the writer's attention to a 
skunk which had been brought to him for mounting. It was immediately 
recognized as a Hog-nosed or White-backed Skunk, belonging to the genus 
Conepatus, a Middle and South American group, ranging as far north as 
Albuquerque, New Mexico; at least this was the northernmost record until 
the above-mentioned specimen was secured on Little Fountain Creek, 
southwest from Colorado Springs. The Biological Survey refers it pro- 
visionally to Mearns' Skunk, Conepatus mesoleiious mearnsi. These ani- 
mals are distinguished by having the nose prolonged into a naked, some- 
what piglike snout, a single broad white stripe on back and tail, and very 
long, strong claws on the fore feet. They subsist very largely on grubs 
and insects which they dig from the ground with their claws or root up 
with the nose. This sudden and unexpected discovery raises the question 
whether this species has been hitherto overlooked, or whether one or more 
individuals may have wandered north far from the usual range. I should 
bo pleased to hear from anyone knowing of similar occurrences in Colo- 
rado. 

BADGER. 

The Badger is a rather unnecessarily maligned animal. True, it does 
dig big holes in the ground into which a horse may thrust a leg, giving its 
lider a bad fall and possibly also breaking the leg in the hole, but the 
chances are that the hole was dug in order to get a prairie dog for dinner, 
so that the Badger had a really good excuse for digging. As a matter of 
fact badgers are quite useful animals, destroying many prairie dogs, 
ground squirrels and similar vermin. Their powerful forelegs and paws 
armed with long stout claws are efficient tools for excavating, and the 
flattened, compressible body is excellently adapted for underground work, 
while the heavy coat of long, coarse hair protects the body from dirt and 
dampness. Badgers range all over Colorado, living both on the plains and 
in the mountains, even up to timberline. 

I once saw a badger traveling along after a couple of coyotes. A friend 



has told me of a similar instance, and Thompson Seton makes mention 
of another. The object of the association is unknown. Can any of my 
readers offer any information, or give any further occurrences of this 




No. 3. Badger, Taxidea tnxus. 

nature? Badgers are too often killed at sight, which is to be deplored, 
for they are too useful to be destroyed. While the fur has a certain value 
it is hardly enough to make it worth while to kill them merely for that. 
The scientific name is Taxidea taxus. Mr. J. D. Figgins has recently de- 
scribed a subspecies. Phipps' Badger, T. 1. phippsi, from southwestern 
Colorado. 



Leaving the carnivorous animals which have just been described we 
come to the rodents, which group comprises by far the larger number of 
the mammals to which we apply the term "small". They are easily identi- 
fied by the large incisor teeth, two each in the upper and lower jaws. 
Rabbits, while they also have long incisors, have four in the upper jaw, a 
small pair behind the large front ones, and because of this and other 
structural differences are now placed, together with the conies, in a sepa- 
rate order, the Lagomorpha, which means literally having the form of a 
hare. 

GRASSHOPPER MICE. 

The first of the rodents on our list are the Grasshopper Mice, or 
Scorpion Mice as they are sometimes called, belonging to the genus 
Onychomys, which is confined to western North America, ranging from the 
plains of Alberta, Saskatchewan and Manitoba, south to central Mexico, 
-and east to western Minnesota and eastern Kansas. These animals are 



10 



near relatives of the deer mice, but are easily distinguished from the 
latter by their heavy bodies, short tails and usually paler colors. They are 
dwellers in the open country, never, to the best of my knowledge, found 
in underbrush or about rocky places. They live largely, if not entirely, 
in holes in the ground, sometimes in holes abandoned by other animals, 
such as prairie dogs, for I have taken them at the old burrows; and they 
may dig homes for themselves, as they have good, strong fore paws and 
claws and are often taken at small holes on the prairie. As might be in- 
ferred from the names, they eat animal as well as vegetable food, destroy 
a good many insects such as grasshoppers and beetles, and are called 
"Scorpion Mice" because they eat scorpions when found. One which I 
kept in confinement for a short time preferred raw meat to any of the 
vegetable foods I offered it. Their animal diet causes them to decompose 
much more rapidly after death than mice which feed mainly on vegetable 
matter. They have a considerable range in altitude, being found from 
the lowest elevations in the state to as high as 8,500 feet in North Park. 

The species are all bicolored, the under parts and feet being white, 
while the color of the upper parts in adults of course varies in different 
species, but is generally some tawny color, occasionally quite reddish in 
individuals. The young, as in the case of the deer mice, are blue or mouse 
gray in color, gaining the adult colors with maturity. They breed in spring 
and summer, having from three to six young in a litter, four probably 
being the average number. 

The body is stout and heavily built, and while the total length is 
about the same as that of the deer mice inhabiting the same regions, the 
Grasshopper Mice look larger because of the proportionately shorter tail. 
The total length is six inches or a trifle less, and the tail 1.7 inches. 

In Colorado we have two species or rather subspecies of these ani- 
mals, Seton's Grasshopper Mouse, Onychomys leucogaster arcticeps, and the 
Black-browed Grasshopper Mouse, Onychomys leucogaster melanophrys, the 
two having separate distributions, but together inhabiting most of the open 
prairie and park country of the state, and, as before stated, attaining an 
altitude of 8,500 feet in North Park. 

HARVEST MICE. 

The Harvest Mice, whose generic name is Rheithrodontomys, are small 
animals inhabiting in North America the two Sonoran zones. East of the 
Mississippi river they do not occur north of the Ohio and Potomac valleys, 
whereas in the western United States they range into North Dakota, Mon- 
tana and Washington, and southward through Mexico and Central America 
to Panama. In Mexico and Central America the genus ranges from the 
tropical zone at or near sea level through all the zones to and including 
the Canadian at timberline. Howell, in a recent revision of the genus, 
recognizes fifty-eight forms, of which four are found in Colorado. 

The members of this genus can always be recognized by the upper 
incisors each having a longitudinal groove. This groove is very fine and 
one sometimes has to look quite closely to find it. While they have a 
superficial resemblance to the deer mice, they are smaller in size, with 
proportionately longer tails, which are slender, scaly, and thinly haired. 
The ears are prominent. 

Our Harvest Mice are dwellers in the open, preferring places over- 
grown with grass or weeds. One of the Colorado species, the Pallid Harvest 
Mouse, is found only in dry, sandy uplands. In the dry western regions 
these mice in general are apt to frequent the grassy borders of sloughs, 
small streams, and irrigation ditches. The nests are built of grass, lined 
with soft materials, and placed either on the ground, or above it in bushes 

11 



or low trees. They travel in runways of their own, and also in those 
made by other mice, and are out both by day and night. The food is 
mainly seeds and grain, with some green vegetation. The young are four 
or more in number, and they appear to breed throughout spring and 
summer into the fall. 

Gary noted one at Wray moving about in the brush and often winding 
its tail around a twig to assist itself. The writer found one at Barr under 
an old piece of sheet iron lying on the prairie. 

The colors of the various forms in Colorado vary from light buff to 
various shades of brown, usually light, but often, if not always, mixed with 
blackish hairs. The tail is bicolor, brown above, lighter or white below. 
Adults vary in length from 4.8 to 5.95 inches, and the tail from 2 to 2.5 
inches. 

The Harvest Mice occurring in Colorado are the Pallid Harvest Mouse, 
Rheithrodontoinys albescens albescens; the San Luis Valley or Mountain 
Harvest Mouse, R. moiitanus; the Aztec Harvest Mouse, Rheithrodontoinys 
megalotis azteciis; and the Prairie or Nebraska Harvest Mouse, R. m. 
dychei. 

The Mountain Harvest Mouse is interesting from the fact that the 
first specimen was taken by one of the Pacific Railroad surveying parties 
in August, 1853, and was described by Baird in 1855. The type specimen 
long remained unique. A single immature specimen was taken by Vernon 
Bailey at Del Norte in 1904. In the fall of 1907 Merritt Gary went to the 
Medano Ranch, 15 miles northeast of Mosca, probably not far from the 
place at which the type was taken, and collected a considerable series of the 
animals, enabling a detailed study to be made for the first time. He found 
them on a low sandy ridge running through the meadows on the ranch, 
The present writer was unable to secure any at the same place two years 
later, but did take one at Crestone, several miles farther north. 

As a whole the distribution of Harvest Mice in Colorado is not 
very well known. They seem to be quite common in northeastern Colorado, 
have been taken at Canon City, and are also found in various portions of 
southwestern Colorado. I have not found them at Colorado Springs, nor 
did I take any in southeastern Colorado in 1905. 

DEER MICE OR WHITE-FOOTED MICE. 

Of our native wild mice probably the best known to outers are those 
belonging to the group collectively known as Deer Mice or White-footed 
Mice, the former name being derived from the tawny color of many of the 
species, something like that of the red coat of a deer, and the latter from 
the fact that most of them have white feet. They are members of the 
genus Peromyscus, a very large group which has been subdivided into 
several subgenera. In Colorado we have no less than eight species and 
subspecies. 

There is more or less similarity in the habits of all these. They are 
strictly nocturnal. It would be difficult to find a locality or situation 
which was not inhabited by one or more species. In certain portions of 
Colorado I have found four species in the same locality. They are sure 
to be found about rocks, and dead logs and brush. The banks of the dry 
arroyos of the prairies often have holes inhabited by these mice. Traps 
set in meadow mice runways in wet grassy places usually yield their quota 
of deer mice. In short, they are practically everywhere. In altitude they 
range from the lowest elevations up to timberline at least. Osgood says: 
"Throughout practically all of the western United States they exist in 
countless numbers, perhaps exceeding those of the other combined mam- 
malian inhabitants of the region." 

Usually, so far as my observations go, living in holes in the ground 

12 



or about rocks and logs, they will occasionally make their nests of grass 
and other soft materials under boards or pieces of sheet iron lying on the 
ground. In places where the common house mouse is not found they 




No. 4. Tawny Deer-mouse, PeromyKcu.s ni. rnflmix. 

often come into houses and other buildings and act much as the latter does. 
From my bed I have seen mice running about the floor of a log cabin. 
The least movement and away they scampered. 

Their food consists of almost anything, I think. Seeds and berries of 
all sorts, and meat is also eaten. They nibble about dead carcasses, and 



No. 5. Long-nosed Door-mouse, I'cromyseus iin.sutus. 




when several are confined together in a cage, they are sometimes, but not 
always, cannibalistic enough to eat their own kind. Grain is sometimes 
carried away from the farmers' stacks, and because of their large numbers 
they may do considerable damage. 

The first coat of the young is a bluish gray in color, quite different 
from that of the adult, which is not attained until the animal is full 
grown, or nearly so. 

Some of our species are about the size of the common house mouse, 
others are noticeably larger. The smaller species have a total length of 
six inches, including the tail, which is 2.6 inches, and our largest species 
is 7.5 inches long, half of which is included in the tail. Our eight species 
may be divided into two groups, one of which we will call the small-eared 
group, and the other the big-eared group. The species belonging to the 
former are the Tawny Deer Mouse, Peromyscus maniculatus rufinus; the 
Nebraska or Black-eared Deer Mouse, P. in. osgoodi; the Yellow Deer 
Mouse, P. m. nebrascensis; and the Tornillo Deer Mouse, P. leucopus tor- 
iiillo. The big-eared species are the Golden-breasted Deer Mouse or Buff- 
breasted Canon Mouse, P. crinitus auripectus; Rowley's Deer Mouse, P. 
boylc-i rovvleyi; True's Deer Mouse, P. truei; and the Long-nosed Deer 
Mouse or Estes Park Cliff Mouse, P. iiasutus. 

The mice of this latter group appear to make their homes more ex- 
clusively about rocky places than those of the first group. Thus, in 
southwest Colorado I found the Tawny, Rowley's, the Golden-breasted and 
True's Deer Mice all living among the rocks in a canon of the Dolores 
river, but only the first-named was taken elsewhere, as for instance out 
in the sage brush and greasewood, and this has been my experience in 
other localities. 

WOOD RATS. 

Most of us Colorado people have met with Mountain Rats, Wood 
Rats, Pack Rats, or Trade Rats, as they are variously termed, for one 
species or another is found over the whole area of the state, though in 
some of the eastern counties they are very locally distributed because of 
the lack of country preferred by them. There are in all ten species and 
subspecies of these animals found in Colorado, six belonging to the round- 
tailed group and four to the bushy-tailed group. They all belong to the 
genus Neotoma, the bushy-tailed animals being placed in the subgenus 
Teonoma, while the round-tailed belong to the subgenus Neotoma. 

The genus, with six other allied genera, belongs to the subfamily 
Neotominse, which is confined to North and Middle America, from Nica- 
ragua and Guatemala northward into Alaska and northern Canada to 
latitude 62, and in the southern United States from the Atlantic to the 
Pacific. There are no other animals in this state with which any of the 
species is likely to be confused, unless it be the common brown rat, and 
the naked tail of this animal at once suffices to distinguish it, as the 
tails of our native species are all haired, while none of them are at all 
like the brown rat in color. 

The various Wood Rats have at least one habit in common, no matter 
where they may happen to live, and this is the accumulation of piles of 
trash and rubbish about their nests, or nest sites when the nests happen 
to be in holes. These accumulations are also placed away from the nests 
at times. It is the habit of carrying away articles of all sorts which has 
given these animals the names of "Pack Rats" and "Trade Rats", 
the latter because of a myth that something is left in exchange 
for what is taken. Where there are rocks the nests are in holes 
or crevices, but the pile of trash is ever present, and it is also there 

14 



when, as is sometimes the case, the nest is in a hollow tree. Some of 
the species make nests under bushes or tree cactus, piling a heap of 
stuff over the nest. It would be easier to say what is not in these heaps 




Bailey's Wood-rat c 

Photograph by Herman W. Nash. 



nileyi. 



than what is, for anything portable is carried to them, sticks, bones, cow 
chips, horse dung, pieces of metal, rags, anything not too much for the 
animal's .strength. Nor do the animals always take their booty to the 
nests. A lot of knives, forks and spoons were once missed from a mine 




No. 7. Nest of Bailey's Wood-rat. Photograph by Herman W. Nash. 
15 



cabin which had been unoccupied all winter, and were found under the 
floor, but not at a nest. Another rat industriously carried chips from a 
wood pile into a blacksmith shop and dropped them into a barrel standing 




No. 8. Bailey's Wood-rat, female with two young. 
Photograph by Herman W. Nash. 

(here. The surroundings of the nests always appear decidedly untidy 
because of the rubbish piles and the dung of the owners scattered about, 
though it is said that the nests themselves are always clean and tidy. 

All the species are usually nocturnal, but they may occasionally be 
seen in the daytime. Their food is mainly of a vegetable nature, though 
they will occasionally eat flesh. All sorts of fruits, seeds, berries and 
nuts are eaten, and no doubt such insects as may be captured are de- 
voured. 

I think but one litter of young in a season is the rule for our species. 
The offspring are born late in the spring or early summer, and are from 
three to six in number. 

Our smallest species, the Desert Wood Rat, has a total length of 11.25 
inches, of which the tail occupies 4.8 inches, while the largest species, the 
Mountain Rat, is 15 inches or more in total length, with the tail 6.3 
inches. 1 have measured specimens which were 18 inches over all, but 
these were unusually large. 

The names of those of our Wood Rats included in the Round-tailed 
Group are as follows: Bailey's Wood Rat, Neotoma floridana baileyi; 
Baird's Wood Rat, N. micropus micropus; Hoary Wood Rat, N. m. canes- 
cens; Warren's White-throated Wood Rat, N. albigula warreni; Gale's or 
the Colorado Wood Rat, N. Mexicana fallax; and the Desert Wood Rat, 
N. desertorum. The Bushy-tailed Group includes: the Mountain Rat or 
Colorado Bushy-tailed Wood Rat, X. cinerea orolestes; the Arizona Wood 
Rat, N. c. arizona?; the Cinnamon Wood Rat, N. c. cimiamomoa; and the 
Pallid Wood Rat, X. c. rupfcola. 

Of our various species the Mountain Rat is perhaps the most widely 
distributed. Beginning with the upper foothills of the Front and Pikes 
Peak Ranges it extends westward through the mountains, and even down 

16 



to such low altitudes as Grand Junction, 4,600 feet, giving one of the 
greatest zonal ranges of any Colorado mammal. 

This' species is the Mountain Rat, I am tempted to say of fable, and 



mmt 




X<>. 0. Mountain Rat or Pack Rat, Xeatomn cinerea orolentcs. 

Photograph by Charles E. Mace. 

certainly many fables have been told about the creature, which is well 
known to all dwellers in its range. Were you ever in a cabin or house 
which had a canvas or cloth ceiling, and where a rat lived? And after 
you had turned in did you not enjoy having that rat run foot races with 
himself all over that canvas, making as much racket as a four-horse 
team? One rat can certainly give a fellow the impression that there are 
a dozen of them scampering about up there. Perhaps when you roll out 
in the morning and pull on your shoe you find a nice chip tucked away 
in the toe. Merely Brother Rat's playfulness. Some of your smaller be- 
longings may be missing and you find them elsewhere than where you 
left them the night before, or even do not find them at all. Your friend 
was very busy while you slumbered. 

Wherever these rats are found they make their homes in every 
imaginable location. Among other places they go into abandoned mine 
tunnels, among the drifts and timbers. I took one in an old tunnel at 
Querida, Custer County, at a point 29, 5 feet from the entrance. It is in 
the fall and winter that these animals are most prone to come into habita- 
tions and other buildings, though they are just as likely to come into an 
empty' house, a stable, or an abandoned shaft house as into an occupied 
dwelling. I have seen green aspen leaves in their piles in at least two 
cases, and actually saw a rat eating one of the leaves. At the same place 
were pieces of fungus from dead logs, apparently gathered for food. 



17 



MEADOW MICE OR FIELD MICE. 

The group or family of mammals known as Field Mice, Meadow Mice, 
or Voles is of wide distribution, being found over practically the whole of 




No. 10. Nest of Mountain Rat; found on sill under a building, removed 
to outside and placed on steps in same position with respect to the 
boards as in its original location; composed almost entirely of 
shredded sunny sacks. 



the northern hemisphere outside of the tropical regions. Technically it is 
known as the subfamily Microtiiue, and it is represented in Colorado by 
four genera, Microtus, comprising what may for convenience be termed 
the true Meadow Mice; Evotomys or the Red-backed Mice; Phenacomys, 
the Mountain Voles or False Lemming Mice; and Fiber or Ondatra, the 
Muskrats. 

Except the Muskrats these are all small, heavy-bodied, short-tailed 
animals, leading terrestrial lives in grassy places, usually damp by prefer- 
ence, or in the woods, among fallen logs or about the brush, and in Colo- 
rado at all elevations from the plains to above 14,000 feet. Their food is 
largely vegetable, consisting of grasses and other green stuff, as well as 
seeds and bark. It is by gnawing the bark of fruit trees that much dam- 
age to orchards is done by these mice. None of the species is known to 
hibernate. 

Of these four genera the Muskrats are easily distinguished by their 
large size and general adaptation to a semiaquatic life; and the Red-backed 
Mice, as their name suggests, by the reddish color of the back. The two 
remaining genera are more difficult to distinguish from one another, and 
as a matter of fact the Mountain Voles were for a long time confused 
with the other Field Mice until Dr. C. H. Merriam discovered that their 
molar teeth had root^ while the molars of the others were always rootless. 
The Colorado species of Mountain Voles have a proportionately much 

18 



shorter tail than our various species of Field Mice, with one exception, 
and that one is not likely to cause any confusion. 

Of this family the Field Mice have the greatest number of species in 




No. 11. Cantankerous Vole, Microtug mordax; about two-thirds life size. 

Colorado, namely five, and they are found almost everywhere except in 
the driest prairie regions. When living in grassy places they make 
numerous runways through the grass, along which they travel and which 
are utilized by the other small mammals inhabiting such places, such as 
deer mice and shrews. Their holes are not far from the runways, and in 
the burrows are globular nests of grass and other plant fibers. In addition 
to having holes these mice make nests on top of the ground of the same 
materials as the underground nests, and they also make nests under pieces 
of board or sheet iron which may be lying about. 

The names of our Field or Meadow Mice are as follows: The Saguache 
Meadow Mouse, Microtus pennsylvanicus modestus; the Dwarf Meadow 
Mouse, M. namis; the Cantankerous or Rocky Mountain Meadow Mouse, 
M. mordax; the Pigmy Meadow Mouse, M. pauperrimus; and Hayden's 
Meadow Mouse or Upland Mouse, M. ochrogaster haydeni. 

RED-BACKED MICE. 

The Red-backed Mice, genus Evotomys, are, as previously stated, dis- 
tinguished from the other Colorado meadow mice by the reddish color of 
the back. The genus is circumpolai in distribution, and ranges little, if 
any, below the Canadian Zone. The species found in Colorado is the Colo- 
lado Red-backed Mouse, Evotoinys gapperi galei. 

In Colorado 8,000 feet is about the lowest altitude to which this species 
ranges. Whether it is to be found above timberline I cannot say as there 
are no records bearing upon this point, but it is confined to the boreal 
zones. It lives in the woods and is found about the fallen logs, making 
its nests both under logs and in burrows. It does not hibernate and is not 
known to lay up any stores of food for winter use. Its food is seeds of 

19 



various sorts, also grass. From four to six young are born in a litter, and 
the breeding season extends from May into July. 




Xo. 12. Nest of Colorado Red-backed Mouse, Evotomys Capper! j^nloi; 

on ground under piece of building paper. Photograph by 
Albert Haanstad. 

MOUNTAIN LEMMING MICE OR VOLES. 

It is difficult so to describe the Mountain Voles that a layman can 
distinguish them from the true Meadow Mice. They are small animals 
with proportionately shorter tails than most of our species of Meadow 
Mice. The most certain distinguishing characteristic is the molar teeth, 
each of which has two roots in the adult animals, while the molar teeth 
of the Meadow Mice have no roots, the portion which is seated in the jaw 
being the same shape as the external portion. 

The name Pheiiaconiys means "false mouse", and was given because 
the members of the genus had* been placed in Microtus because of their 
external resemblance to that genus. The genus is North American and is 
confined to the boreal regions of the continent and higher elevations of 
the Rocky and other western mountains. There are two species in Colo- 
rado, the Mountain Lemming Mouse or Idaho Mountain Vole, Phenacomys 
oropliilu^, and Treble's Lemming Mouse or Mountain Vole, P. preblei. 

Vernon Bailey, in his account of the mammals of the Glacier National 
Park, says this species lives in burrows in the grassy parks, and makes 
tiny runways through the grass from one burrow to another, but both 
the burrows and runways are well concealed. The animals are largely 
nocturnal. They seer- to eat much green vegetation. The nests appear 
to be entirely underground. They apparently have in a season several 
litters of from four to six young. 

At present Preble's Mountain Vole is known only from the type local- 

20 



ity, which is Twin or Lillie's peak, near Long's peak, at 9,000 feet, and 
from North Boulder creek, also at about 9,000 feet elevation. The type 
was taken in a perfectly dry locality covered by forest, most of which 
had fallen. 

MUSKRATS. 

The Muskrat is well adapted to the semiaquatic life which it leads, 
having a dense close under fur with long guard hairs which it is almost 
impossible to wet through, at least while the animal is alive, an almost 
naked tail flattened vertically, and large webbed hind feet set obliquely 
to the leg so that they can be turned edgewise when carried forward. The 
ears are small and hidden in the fur. It makes its home in holes in the 
banks of streams and ponds, and houses of mud and grass are also built 
in shallow water. Even though it is extensively trapped for its fur it is 
still abundant, and is almost as much so in closely settled regions as in 
the wilderness. At least civilization seems to have no terrors for it, and 
the proximity of mankind does not drive the animal away. (After I had 
written the preceding I learned that in Minnesota and elsewhere the catch 
of Muskrats had decreased greatly the last year, the decrease being ap- 
parently due to overtrapping during the period of extraordinarily high 
prices for furs.) The food is grass and other vegetation; we often see 
on the waters of ponds floating grass which these animals have cut for 
lood. Where fresh water mussels occur these are brought up from the 
bottom and opened by biting the hinge between the two valves, whereupon 
the contents are devoured. 

While more or less of nocturnal or twilight habits the Muskrat is 
often seen about in the daytime, especially when not much disturbed, 
sometimes swimming or feeding, or sunning itself in some convenient 
place. Trails are often worn through the grass where the animals come 
up from the water or travel across from one water to another. The litters 
are large, up to twelve in number, and are born from May to July, and 
probably at least two litters in a season are the rule in Colorado. 

Two species are found in Colorado, the Rocky Mountain Muskrat, 
Ondatra zibcthicus osoyooensis, which is the Muskrat found west of the 
summit of the continental divide and the Sangre de Cristo Range; and 
the Great Plains Muskrat, O. z. cinnnmominus, the species of the plains 
region, but ranging up the eastern slopes of the mountains as high as 
Ward, Boulder County. The summits of the ranges appear to form the 
barrier between this and the Rocky Mountain Muskrat. 

POCKET MICE. 

The daintiest little animals we have are the smaller species of Pocket 
Mice, the bodies of some of which are hardly as large and long as two 
joints of one's finger, and which are clothed in a soft, silky fur. Unfortu- 
nately one seldom sees them in life as they are practically exclusively 
nocturnal. They have cheek pouches, or pockets with external openings, 
hence their name, these pouches being used for carrying food. These mice 
make their homes in burrows as tiny as their occupants, often about 
yuccas o'r among low bushes, and sometimes with little trails leading from 
one to another. The entrances are often closed during the day. Not all 
these mice make small burrows, for the large Kansas Pocket Mouse makes 
a good-sized hole, often going straight down into the ground. The food 
consists -of the seeds of any of the plants occurring in their habitat. 

Pocket Mice are nocturnal in their habits. Some of the species are 
among our very smallest mammals. Our smaller species vary in total 
length from 4.5 to 5.5 inches, the tail being from 2 to 2.65 inches. The 
Kansas Pocket Mouse has a total length of 8.75 inches, and tail 4.25 

21 



inches. There are six species of Pocket Mice recorded as actually having 
been taken in Colorado, as follows: The Buff-bellied Pocket Mouse, 
Perognathus fasciatus inf raluteus ; the Plains Pocket Mouse, P. flavescens; 
the Black-eared Pocket Mouse, P. apache melanotis; the Colorado Pocket 
Mouse, P. a. caryi; Baird's Pocket Mouse, P. flavus, and the Kansas Pocket 
Mouse, P. hispidus paradoxus. In color they are various shades of buff, 
with many black or blackish hairs mingled in the back. They are found 
in the prairie and other dry regions of the state. 

KANGAROO RATS. 

Kangaroo Rats are an exclusively western group of mammals, ranging 
from Oregon well south into Mexico, and always confined to more or less 
arid regions. Like the Pocket Mice and Pocket Gophers they have external 
cheek pouches, opening on the outside of the mouth, not on the inside as 
in the case of the chipmunks and similar animals; these pouches are lined 
with hair and are used for carrying food to the nests and storage places. 
Their hind legs are greatly elongated, and the tail is extremely long, with 
a tuft or pencil at the tip, and is well-haired its full length. All the 
species have certain markings in common, these being more or less dis- 
tinct crescentic black facial lines, white spot over eye and behind ear, and 
a white stripe across the thigh. The upper parts are buffy, with more 
or fewer black hairs; the under parts and feet white. The tail has a dark 
stripe above and another below, with white between. The pencil is dark. 
The total length is about ten inches, the tail about six. 

We have four forms in Colorado, the Mountain or San Luis Kangaroo 
Rat, Perodipus ordii montamis; the Moki Kangaroo Rat, P. o. longipes; 
the Wyoming Kangaroo Rat, P. o. luteolus; and Richardson's Kangaroo 
Rat, P. o. richardsoni. They inhabit many of the lower arid portions of 
the state. 

The habits of these animals are very interesting. While mainly 
twilight or nocturnal, as their large eyes would lead one to suspect, yet 
they do occasionally go abroad by daylight, and the individual whose 
picture is shown here was captured in the daytime in the San Luis Valley 
where it was out among the greasewood and sage brush. Two of us had no 
difficulty in running it down and taking it in our hands. It did not appear 
to leap in trying to escape, but rather to run. They live in burrows, 




No. 13. Mountain Kangaroo Rat, Perodipus montanus. 
22 



usually preferring sandy soil, and often throw up quite good-sized mounds, 
to which there are several entrances, each with a well marked trail leading 
from it. The entrances are often closed during the day. Frequently the 
holes are under a bush or yucca, and almost invariably there are two 
entrances, one on either side of the bush. Trails run from one bush to 
another, and the colony is a network of trails. I have on a few occasions 
dug out burrows, but without gaining much information as to the habits 
of the owners; but I may have been unfortunate in my choice of digging 
places. They are quite social and live in colonies of various sizes, a num- 
ber of holes being found not far apart. 

The food is principally seeds of various kinds, and leaves of som? 
plants are also eaten. Stores are laid up in the burrows against scarcity 
and inclement weather, for while they do not hibernate, they may remain 
within doors during cold or stormy weather. The food is placed in the 
cheek pouches with the fore paws, used like hands. When it is desired 
to empty the pouches the animal puts its fore paws behind the pouches 
and brings them forward, pressing against the face at the same time, thus 
forcing out the contents. I have seen a pocket gopher do this and the 
movements are very quick. 

JUMPING MICE. 

The Jumping Mice, which must not be confused with the Kangaroo 
Rats, belong to the genus Zapus, a small group which with the exception 
of one species is confined to North America. They are small animals, 
with bodies about the size of House Mice, with the hindlegs greatly elon- 
gated, and with very long tails. Of some twenty known species and sub- 
species two have been found in Colorado, the Prairie Jumping Mouse, Zapus 
luidsonius campostris, and the Rocky Mountain Jumping Mouse, Zapus 
priiu-eps. The former has been found in various counties in northeastern 
Colorado, while the latter appears to be pretty generally distributed 
through the mountainous portions of the state. 

The color is buff, which on the back is much darkened by blackish 
hairs, so that the animal appears to have a wide buff stripe on either side. 




Rocky Mountain Jumping Mouse, K:ipu.x princcpM; about half 
life size. 



23 



The under parts are white with some buff. The tail is bicolor, dusky 
above, whitish below. The total length is about 9 inches, and tail 5.5 
inches. These animals live in meadows, along the edges of woods, and 
in shrubby fields, showing a preference for moist places. I have taken 
them near streams in quite heavy timber in the mountains, and also in 
open ground along small spring runs. In Colorado the altitudinal range 
is up to above 9,000 feet. The nests are of grass, sometimes under- 
ground, sometimes above, in the grass or by small bushes. Five or six 
young are born in late spring or early summer. The food is seeds and 
similar material. They hibernate in holes underground, but may come out 
for a short time in mild weather. 

PORCUPINE. 

Yellow-haired Porcupine (Erothizon epixanthus) is the name of our 
prickly friend whose work is often seen in the forests in the shape of bare 
spots on the trunks of trees where the bark has been gnawed away. Some- 
times the trees are girdled and die, more often the bare places are scattered 
here and there on the tree and do no permanent harm except possibly by 
affording opportunities for insect enemies of the tree to begin their de- 
structive work. With their powerful claws and limbs porcupines are 
excellent though usually rather slow climbers, yet can scuttle up a tree in 
fairly lively fashion if alarmed. The bark of trees forms their principal 
article of diet. They are by preference frequenters of the coniferous 
forests, but at times wander away and have even been captured on the 
plains well away from the foothills. The young are from one to four in 



3 ^ 
K p 



P g 




No. 15. Yellow-haired Porcupine, Erethizon cpixunthum. 

24 



number, are born with their spiny armament already developed, and are 
large as compared with the size of the parent. 

In spite of the protecting quills some animals are brave enough or 
reckless enough to kill and eat porcupines. Mountain lions are said to do 
it, and other animals may do so. I have seen the remains of porcupines 
which had been killed and eaten, and evidently the victim had been turned 
on its back and the belly opened. Beside the damage done to trees porcu- 
pines are frequently nuisances about cabins, gnawing anything which has 
been handled by man, apparently attracted by the salty flavor left by 
perspiration, and cabin floors are often badly damaged by the powerful 
teeth of these animals. The flesh is palatable, or at least eatable, though 
personally I can plead guilty to having eaten but one, or my share thereof, 
a half grown animal which came about our camp at Mud Springs on White 
River plateau and disturbed our slumbers. As we were out of meat it was 
decided that a fitting punishment for the animal was for us to eat it. The 
flesh had a peculiar gamy flavor, different from anything I have ever 
tasted. Adults are about 36 inches in total length, with tail about 9 
inches. They may weigh as much as 20 pounds. The quills are overlaid 
by long guard hairs, and have short hairs mingled with them, and are 
everywhere on the animal except the nose. They are very loosely held to 
the skin and pull out readily when the points enter some foreign body 
such as a dog's nose, for they are barbed and once they have penetrated 
are difficult to extract. 

MARMOTS OR WOODCHUCKS. 

Once we thought there was but one species of Marmot in Colorado, 
but an examination of series of specimens has resulted in the separation 
of our marmots into three forms, all subspecies of the Yellow-bellied Mar- 
mot, Mnrmota flaviventer. They are the Park Marmot, M. f. luteola, War- 
ren's Marmot, M. f. \\arreni, and the Dusky Marmot, M. f. obscura. Mr. 




No. 16. Western Woodchuck, Marmotu flnvivonter; half grown young. 
25 



J. D. Figgins has described a fourth, Campion's Marmot, M. f. campion! . 
The Dusky Marmot is largest and darkest. Marmots are of various shades 
of brown, with more or less black hairs and with white markings about 
the face. The total length is two feet, more or less, and the tail is 8 or 9 
inches long, including the hair. In Colorado, as elsewhere, the vernacular 
names are Woodchuck and Groundhog. The range in altitude inhabited 
by these animals is considerable, as I have taken them in the White River 
country below 7,000 feet, and they reach the summits of the highest 
mountains, being reported from the top of Long's Peak. 

Marmots make their homes in a variety of situations, sometimes dig- 
ging their burrows in the earth on the open hillsides, but more often, I 
think, preferring to live about the slide rock, in which, or under which, 
they can excavate their homes, and which affords a refuge from their 
enemies. Here they lie on top of rocks which command a good view of 
the surrounding country, and sleep in the sun, uttering a sharp whistle of 
alarm when anyone comes in sight. The food is grass and presumably 
other plants. No stores are laid up for the winter, for that season is spent 
in hibernation, which begins usually in October. At that time the animals 
are very fat. The young, four to eight in number, are born in late spring 
or early summer, and may be seen out of the holes the last of June or early 
in July. 

PRAIRIE DOGS. 

Prairie Dogs are such familiar animals to most Coloradoans that it 
seems somewhat absurd to try to describe them in a publication of this 
sort. We are all acquainted with these chunky little animals, which sit 
on the mounds by the holes, ready to pop out of sight at the least indica- 
tion of danger. However, it may be of interest to know that there are 




No. 17. Adult Plains Prairie "Dos, Cynomys liidovicianus; in winter 
pelage. Photograph by Clark Blickensderfer. 



2G 



I'our species and subspecies of these animals in Colorado, as follows: the 
Plains Prairie Dog, Cynomys ludovicianus; the White-tailed Prairie Dog, 
(.'. leucums; Gunnison's Prairie Dog, C. gunnisoni; and the Zuni Prairie 
Dog, C. gunuisoni y.uniciisis. The first named is the prairie dog of the 
plains region east of the foothills, and is the species which lives in the 
largest colonies or towns. The others are found in the large mountain 
parks, and in the open spaces in the western part of the state, but never 
living in such large towns as the preceding. The total length of an adult 
is from 13 to 14 inches, of which the tail occupies 2.5 to 3 inches. The 
color varies, naturally, in the different species, but is some shade of brown, 
with a certain number of black hairs intermingled. The Plains species 
has a black-tipped tail; the others have tails with white tips. The breed- 
ing season is in the spring, and the young are large enough to come out 
of the holes some time in May or early June. The Plains Prairie Dog does 
not hibernate, though it may, in severe winter weather, remain under- 
ground for a few days. The other species, through most of their range at 
least, probably spend the greater portion of the cold weather in hiberna- 
tion, but they have at times been seen out in midwinter in cold weather. 
These animals are of much economic importance because of their 
destructive habits. When living on uncultivated lands they eat the grass 
and other vegetation, consuming what would otherwise feed many cattle 
or sheep. When near farms they do great damage to crops of many sorts. 
Much work has been done in the way of destroying them, and by concerted 
action of the landowners of a region good results can be obtained and the 
pests kept under control. It is hardly needful to say that the good old 
story of the prairie dog, owl and rattlesnake living in the same hole is a 
myth. The two latter animals are likely to live on the prairie dogs rather 
than with them. The snakes, if not the owls, certainly eat the young 
ones. Eagles and various hawks, to say nothing of coyotes and badgers, 
also prey on the prairie dogs. It is not true that the dogs dig deep holes 
to water. Their moisture is obtained from the vegetation they eat. 

CONY. 

To meet these curious and interesting little cousins of the rabbits one 
has to seek the higher elevations and the slide rock, especially the latter, 
lor sometimes the animals follow an unusually attractive rock slide down 
to a comparatively low elevation. Cony is the name by which they are 
universally known through our mountains. "Pika" is a book name of 
whose derivation I am ignorant, and Sir John Richardson, in the 'Fauna 
Boreali-Americana, calls them the "Little Chief Hare". They are really 
very close relations of the rabbits, and no kin to the cony of the Bible 
except as belonging to the class Mammalia. Colorado has two forms 
the Colorado Cony, Ochotona saxatilis, and Figgins's Cony, O. s. figginsi. 

These animals are generally distributed through the mountains at the 
higher altitudes, ranging usually from about 9,000 feet almost to the sum- 
mits of the highest peaks, provided always that they have their favorite 
slide rock to live in, for they are seldom found away from it. Here they 
find innumerable cracks and crevices in which to make their homes, and in 
which they can take refuge from their enemies. Their food consists of 
plants of all sorts, which they gather from the hillsides by their homes, 
and which they store as "hay" for the winter. Sometimes they make real 
little haycocks, in a typical rounded heap, or again the hay is stored under 
Hat rocks. One of their stacks found in New Mexico contained thirty- 
lour different kinds of plants. The plants are gathered by biting off the 
stems and then, raking the ends of several into his mouth, the little hay- 
maker starts for his stack dragging his plunder beside him. 

27 



Conies are diurnal in habit, and when not feeding or making hay, 
spend much of their time sunning themselves on rocks near their nests. 
They have a high-pitched, squeaky note, quite penetrating, and uttered in 




saxatilis. 



a spasmodic fashion. I always think it sounds as though someone had 
squeezed the animal suddenly as one would a toy, making it squeak. 
Nelson renders it by the syllables "eh-eh". They have three or four young 
in a litter, born early in the summer. In winter they probably move about 
in the slide rock, and possibly just on top of it, under the snow, but it must 
be confessed that little is known about their winter habits. The coat is 
rather long and soft, very similar in texture to that of a rabbit, and in 
color is a mixture of brown, gray and black. The total length is about 
eight jnches, with the tail practically wanting. 

RABBITS. 

Our rabbits divide naturally into two groups, one including the Jack 
Rabbits and the Snowshoe Rabbit, the other the Cottontails. The former 
are really Hares, belonging to the genus Lepus, and their young are born 
fully furred and with their eyes open; the latter belong to the genus 
Sylvilagus, and their young are born naked and blind, as is the case with 
our domestic rabbits. The Jack Rabbits divide again into two groups, the 
White-tails and Black-tails, and are found over most of the open parts of 
the state. The Black-tails are confined to the lower elevations, while the 
White-tails range even to above timberline on some of our highest moun- 
tains. There are two subspecies of each, the White-tailed Jack Rabbit, 
L. toAvnsendi campanius, and the Western White-tailed Jack Rabbit, L. 
townsendi townsendi; the Great Plains Jack Rabbit, L. californicus me- 
lanotis, and the Texas Jack Rabbit, L. c. texianus. 

Living as they do in the open, the Jack Rabbits make their forms 
under protecting weeds or low bushes, usually, I think, where they can 

28 



have a good outlook for possible enemies. Two or more litters are born 
in a season, from three to five or six in a litter. 

Though belonging to the same 
genus as the Jack Rabbits, the Snow- 
shoe Rabbit (lj. bairdi) has a very 
different habitat, living in the woods 
or about brushy places in the moun- 
tains, but never in the open. It 
changes its coat according to the sea- 
son, becoming white in winter. The 
White-tailed Jacks in the snowier 
parts of their range do the same, but 
do not become so completely white as 
the Snowshoes. This change takes 
place in October, and the return to 
the brown summer coat begins in 
April. The comparatively enormous 
hindfeet, with wide-spreading toes, make excellent snowshoes, holding'! up 
the animal in the snow. The hindfoot is as long as that of the much larger 
Jack Rabbit, and makes a larger track in the snow. 

COTTONTAILS. 

Colorado is blessed with five species and subspecies of Cottontails, as 
follows: the Nebraska Cottontail, Sylvilagiis floridanus similis; the Rocky 
Mountain Cottontail, S. mittalli pinetis; the Black Hills Cottontail, S. n. 
!>iaii?>ei-i; the Wyoming or Bailey's Cottontail, S. auduboni baileyi; and 
the Colorado Cottontail. S. a. warroni. These various forms occupy sepa- 
rate, though sometimes overlapping ranges. The Nebraska Cottontail is 
confined to the northeastern part of the state, ranging back toward the 




White-tailed Jack Rabbit, 
: ;:. i-amiu-Mtri.s. . 



No. 20. Rocky Mountain Cottontail, S.vlvilnKiiM n. pinetiN. 




foothills, as at Arvada and Littleton, and occupying the country in com- 
mon with the Wyoming Cottontail, but with this essential difference in 
habits that the Nebraska prefers to live in the brush along the streams, 




Younj? Cottontails in nest in alfalfa field. Photograph from 
Colorado Agricultural College, through W. L. Burnett. 

while the Wyoming lives on the more open prairie, about the sage and 
rabbit brush. In other respects the habits of all these animals are similar. 
They occupy almost all kinds of habitats, they live both in burrows and 
in forms, and the young are born naked and blind in nests lined with fur 
from the mothers' breasts. Tn some parts of the mountains the Rocky 
Mountain Cottontail goes nearly to timberline. Ledges of rock with plenty 
of cracks and holes are favorite dwelling places for all the species. On 
the plains cottontails are often found about the prairie dog towns, living 
in abandoned holes. 



30 



BIBLIOGRAPHY. 

I have divided the following brief bibliography into two parts: The 
first includes publications of a more technical character, in all of which, 
however, will be found interesting data on the habits and life histories of 
the groups treated. The second part includes papers pertaining to the 
economic status and habits of the animals: 

TECHNICAL PAPEHS. 

Bailey, V. Revision of the American Voles of the Genus MIcrotus. North 

American Fauna No. 17. 1900. 
Goldman, E. A. Revision of the Wood Rats of the Genus Neotoma. North 

American Fauna No. 31. 1910. 
Hoi lister, N. A Systematic Synopsis of the Mu.skrats. North American Fauna 

No. 32. 1911. 
Hollister, N. A Systematic Account of the Prairie DORS. North American 

Fauna No. 40. 1916. 
Hollister. N. A Systematic Account of the Grasshopper Mice. Proceedings U. 

S. National Museum. Vol. 47, Pp. 427-489. 1914. 
Howell, A. H. Revision of the Skunks of the Genus (him- ha (Mcphitift). North 

American Fauna No. 20. 1901. 
Howell, A. H. Revision of the Skunks of the Genus SpiloKsilo. North American 

Fauna No. 26. 1906. 
Howell, A. H. Revision of the American Harvest Mice. (Genus Ilhelthrodon- 

t oni<k .s.i North American Fauna No. 36. 1914. 
Howell, A. H. Revision of the American Marmots. North American Fauna No. 

37. 1915. 
Jackson, H. H. T. A Review of the American Moles. North American Fauna 

No. 38. 1915. 
Nelson, E. W. The Rabbits of North America. North American Fauna. No. 29. 

1909. 
Osgood, W. H. Revision of the Pocket Mice of the Genus PeroKnnthu*. North 

American Fauna No. 18. 1900. 
Osgood, W. H. Revision of the North American Genus PeroanyncuH. No*rth 

American Fauna No. 28. 1909. 

Preble, E. A. Revision of the Jumping Mice of the Genus Zaputt. North Amer- 
ican Fauna No. 15. 1899. 

OTIIEIl PAPEKS. 

P.urnett, W. L. Report on Prairie Dog Investigations in Colorado. Agricultural 
College Circular 8. 1913. 

P.urnett, W. L. The Prairie Dog Situation in Colorado. Agricultural College 
Circular 17. 1915. 

P.urnett. W. L,. Rodents of Colorado in Their Economic Relations. Agricul- 
tural College Circular 25. 1918. 

Burnett, \V. L. Meadow Mice (.Microtux). Agricultural College Circular 18. 
1916. 

Lantz, D. K. Meadow Mice in Relation to Agriculture. Year P.ook of Depart- 
ment of Agriculture. 1905. 

Lantz, D. K. An Economic Study of Field Mice (Genus Microtus). Biological 
Survey Bulletin No. 31. 1907. 

Lantz, D. E. The Rabbit as a Farm and Orchard Pest. Year Book of Depart- 
ment of Agriculture. 1907. 

Lantz, D. E. The Muskrat. Farmers' Bulletin 396, Department of Agriculture. 
1910. 

Lantz, D. E. The Muskrat as a Fur Bearer. Farmers' Bulletin 869, Department 
of Agriculture. 1917. 

Lantz. D. E. Economic Value of North American Skunks. Farmers' Bulletin 
587, Department of Agriculture. 1914. 

Lantz, D. E. Field Mice as Farm and Orchard Pests. Farmers' Bulletin 587. 
Department of Agriculture. 1915. 

Merriam. C. H. The Prairie Dog of the Great Plains. Year Book of Depart- 
ment of Agriculture'. 1901. 

Warren, E. R. The Mammals of Colorado. Putnam, New York. 1910. 



31 



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