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FIELD MUSEUM OF NATURAL HISTORY

PUBLICATION 220
ZOOLOGICAL SERIES VOL. XII, No. 6

NOTES ON CENTRAL AMERICAN CROCODILES

BY

KARL P. SCHMIDT

Assistant Curator of Reptiles and Amphibians

REPORTS ON RESULTS OF
THE CAPTAIN MARSHALL FIELD EXPEDITIONS

WILFRED H. OSGOOD

Curator, Department of Zoology THE UBHAftf OF Tfff

Mil- 1924
UNIVERSITY OF ILLINOIS

CHICAGO, U. S. A.
May 19, 1924

NOTES ON CENTRAL AMERICAN CROCODILES

BY KARL P. SCHMIDT

The Field Museum of Natural History, through the generous sup-
port of Captain Marshall Field, sent an expedition to British Honduras
and Honduras early in 1923, primarily for the study of reptiles. In a
future paper I hope to present a more complete account of this ex-
pedition, with an annotated list of the amphibians and reptiles collected.
The present paper concerns itself only with the crocodiles collected,
and the field observations of my companion, Mr. Leon L. Walters,
and myself upon them. We were especially interested in securing
crocodiles for museum exhibition, and while we were disappointed in
not finding very large specimens, we were fortunate in finding crocodiles
in great numbers, living in a unique habitat, especially interesting and
suitable for reproduction as a museum group.

BELIZE CROCODILE.

Crocodylus moreletii A. Dumeril.

One of the most interesting and unexpected results of our collecting
in British Honduras was the rediscovery of Crocodylus moreletii at
Belize. This species was described in 1851 by A. Dumeril, from
specimens said to have been collected at Lake Peten, in northern
Guatemala, by M. A. Morelet. It was redescribed and figured by
Dumeril and Bocourt in the "Mission Scientifique au Mexique," in
1870, with the addition of Belize and the Rio Polochic, in eastern
Guatemala, as further localities for the species.

Giinther in 1885, in the "Biologia Centrali-Americana," came to
the conclusion that this form represented only a variety of Crocodylus
americanus (= acutus). He adds to its synonymy the Alligator lac-
ordairei of P. de Borre (Bull. Acad. Belg., (2) 28, p. no, pi., 1869),
described from Belize, and the Crocodylus mexicanus of Dumeril and
Bocourt from Tampico. Boulenger, in 1889, in his "Catalogue of the
Crocodiles in the British Museum," places C. mexicanus in the synon-
ymy of C. americanus, retaining moreletii as confined to Guatemala and
Honduras (=British Honduras). He records no specimens in the
British Museum. Other references to this form are purely nominal,
and the failure of so large and conspicuous a form to appear for so
many decades, together with the facts that young specimens are difficult

79

8o FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

to distinguish from acutus and that the skull of moreletii is scarcely
distinguishable from that of C. rhombifer of Cuba, led Barbour and
Ramsden, in 1919, in their "Herpetology of Cuba" (Mem. Mus. Comp.
Zool., 47, p. 209), to refer C. moreletii to the synonymy of C. rhom-
bifer, with the assumption that it was based on a specimen transported
from Cuba to Central America by Morelet. This procedure is made
highly plausible by the fact that many species of mollusks, collected by
Morelet and said to be from Central America, are apparently Cuban,
M. Morelet having visited Cuba en route to Central America. A further
factor casting suspicion on the validity of C. moreletii is the fact that
the figure of Alligator lacordairei from Belize is not distinguishable
from the young of C. acutus. Dr. C. C. Mook, in his excellent paper
on "Skull Characters of Recent Crocodilia" (Bull. Amer. Mus. Nat.
Hist., 44, pp. 123-268, 1921), omitted C. moreletii from his list, fol-
lowing Barbour in regarding it as synonymous with C. rhombifer.

Belize is situated at one of the mouths of the Belize River, on a
narrow strip of land scarcely higher than sea-level. Immediately to
the west of the city, and cutting it off entirely from the higher land
of the interior, lies the Sibun swamp, a great area of almost impen-
etrable jungle, broken in places by broad areas of cat-tail marsh. In
spite of its slight elevation above the river and sea, its water is fresh.
The only road leading out of the city is bordered on both sides by
this swamp. Along this road there are occasional areas of cleared
higher ground used as pastures, and these open pastures are inter-
sected by ditches. The ditches, which are often choked with floating
vegetation, form an ideal refuge for young crocodiles. In walking
along about five miles of this swamp road at night with a headlight,
one probably sees several hundred small crocodiles by the reflection
from their eyes. The great majority of these are small specimens
under two feet in length. In several trips we saw only three larger
specimens, one of forty-six inches, one of sixty-three inches, and one
of about the same size which escaped us. The smallest specimen we
collected measured eleven and a half inches. The young crocodiles
of the season must have been rather recently hatched at the time of
our arrival in Belize, in late January. They are easily secured by
shooting with number 10 shot in .44 cartridges.

The stomach contents of the smaller specimens (29 to 74 cm.),
show a varied diet with only a small number of vertebrates and a
high proportion of water insects. Of the seven stomachs examined,
all contained insect remains, of which beetle fragments, Carabidae,
Scarabidae (Chalepus), water beetles and their larvae, and water bugs,

MAY, 1924. NOTES ON CENTRAL AMERICAN CROCODILES — SCHMIDT. 81

chiefly Belostomidac, compose the greater part. Four stomachs con-
tained the opercula of snails; three, remains of small Crustacea; and
three, vegetable matter. One stomach, of a 39 cm. specimen, contained
a small fish 4 cm. long. The stomach of the largest specimen examined
(74 cm.), contained a mass of gray mammal hair. All of the stomachs
contained a small amount of fine gravel, much of it small pieces of
quartz. A small hard nutlet may have been picked up as a stone by
the largest specimen. Parasitic worms were present in two stomachs.

With no specimens available of C. rhombifer, the nearest relative of
C. morelctii, I shall limit my description of the specimens at hand to a
comparative discussion of some of the characters which have been
employed in defining moreletii. Reference may be made to the excellent
figure of the dorsal armor of rhombifer given by Barbour and Ramsden
(loc. cit., pi. 12) and to the figure of the skull of rhombifer described
by Mook (loc. cit., p. 194, fig. 8).

The first distinguishing characteristic of the Belize crocodile to
attract one's attention is the dark coloration. In specimens more than
a meter long (specimens a meter and a half in length appear to be
fully adult), the color pattern of the back can be described as black
with yellow spots and markings. In this it agrees, essentially, with
the Cuban C. rhombifer and contrasts notably with the light olive, with
black markings, of C. acutus. In the smaller specimens, (29-39 cm.),
transverse bands of black are discernible, the interpaces being rather
more yellow than black; the most anterior of these bands borders the
dorsal shield in front and extends diagonally backward and downward
on the sides, and is constant in position in the six specimens in which
it appears. It is followed by three or four transverse black bands
anterior to the hind legs, with ten or eleven similar bands on the tail.
In a specimen of 74 cm. length, the amount of black on the dorsal
scutes has increased to such an extent that it is difficult to distinguish
any crossbands. In the largest specimen, there is no trace of cross-
bands, and the yellow is reduced to isolated spots and flecks. It is
difficult to find a color character, or at least to put in words the color
character, to distinguish juvenile moreletii from juvenile acutus of
similar age.

The arrangement and character of the dorsal scutes is very char-
acteristic in C. rhombifer, which has six uniform rows of heavily keeled
shields, C. acutus having four rows, the outer of which are not en-
tirely continuous. C. moreletii has a much greater number of scutes
than C. acutus, but their arrangement tends to be irregular and they
are all very low keeled. There are a greater number of enlarged

82 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

nuchals in C. moreletii, but this is a character by no means well defined.
The scales of the upper side of the limbs are perfectly smooth in C.
moreletii, keeled in C. rhombifer, and slightly keeled in C. acutus. The
diagonal anteorbital ridge, employed by Boulenger as a key character
to set off moreletii and rhombifer from palustris and the supposed
C. robustus, is not well chosen, as it is poorly developed at best in the
present series of specimens of moreletii. The shortness and breadth
of the snout are obvious, but can best be discussed in describing the
skull.

The skull exhibits the more important and definitely definable
specific characters of C. moreletii. These, in general, ally it to C.
rhombifer even more plainly than the external characters. In a dorsal
view of the skull of the largest available specimen (PI. VI, fig. I,
and PI. VII), its massiveness and its greater breadth anteriorly
distinguish it well from a skull of acutus of similar size. The flare
of the posterior quadrate- jugal angles in acutus disguises the propor-
tionate breadth of the skull if this measurement is used. A useful
measurement appears to be the breadth at the tenth tooth. The absence
of distinct preorbital ridges in moreletii appears to distinguish it to
some degree from C. rhombifer. The square form of the posterior
part of the skull and of the cranial table distinguish the skull of moreletii
from both rhombifer and acutus. The eyelid bones are smaller and
of a different shape in moreletii from those of acutus.

In the lateral view (PI. VI, fig. 2), the nearly straight profile and
the great depth of the skull distinguish it from acutus and ally it to
rhombifer. The posterior teeth are all very blunt and rounded, sug-
gesting that they must belong to an old, or at least fully adult specimen.
This condition suggests a mollusk or crab-eating habit. The posterior
teeth of rhombifer also are notably blunt. Age is also suggested by
the arch of the palatal surface, which is only matched in the largest
skulls of acutus available for examination. The festooning of the
lateral border of the maxillary is noteworthy.

From the palatal view (PI. VIII), the most noteworthy character
is the transverse premaxillo-maxillary suture. In this it agrees with
rhombifer, and I believe that this is the most dependable character for
distinguishing doubtful juvenile specimens. The suture is easily ex-
amined in alcoholic specimens by lifting a flap of skin on the palate.
The relatively short extension of the palatines anterior to the palatal
fenestrae is similar to the condition illustrated by Mook for rhombifer.

The following are measurements in millimeters of two skulls of
C. moreletii, with those of a third from the flesh, and those of C.

MAY, 1924. NOTES ON CENTRAL AMERICAN CROCODILES — SCHMIDT. 83

rhombifer (after Mook) and of a specimen of C. acntus for com-
parison.

C.moreletii C. rhombifer C.acutus

F.M.N.H. F.M.N.H. F.M.N.H M.C.Z. F.M.N.H.

4432 4431 4430 4032 5775

a. Snout to supraoccipital 113.0 170. 218.0 280. 235.0

b. Snout to ends of quadrates 122.5 246.0 320. 257.0

c. Length of snout 67.5 104. 141.5 180. 158.0

d. Breadth of snout at base 38.5 65. 88.0 112. 67.5

e. Breadth at loth tooth 33.5 52. 70.5 84. 52.5

f. Breadth at quadrato-jugals 56.0 114.0 160. no.o

g. Breadth cranial table (ant.).... 30.0 63.0 73. 52.0

h. Breadth cranial table (post.).... 32.5 50. 68.0 102. 60.5

Ratio f/a 50 .... .51 .57 -47

Ratio d/c 57 .62 .62 .62 .43

Ratio e/a 30 .31 .32 .30 .22

The occasion of the addition of a species to the recognized croco-
dilian fauna of America may warrant a synopsis of the American
species of crocodiles. These may be distinguished from all other
American crocodilians (Alligator, Caiman, and Jacare) by the notch-
ing of the skull for the fourth lower tooth, which is thus visible from
a lateral view.

A. Premaxillo-maxillary suture transverse; snout notably short
and broad.

B. Cranial table nearly parallel-sided; dorsal scutes irregular
and with low keels. (Tampico to Belize).

Crocodylus moreletii.

BB. Cranial table much narrowed in front; dorsal scutes strong-
ly keeled, in six regular longitudinal rows. (Confined to

Cuba) Crocodylus rhombifer.

AA. Premaxillo-maxillary suture produced backward; snout mod-
erate or slender.

B. Mandibular symphysis extending to the seventh or eighth
tooth ; nasal bones not reaching the external narial aperture.

(The Orinoco River) Crocodylus intermedius.

BB. Mandibular symphysis extending to the fourth or fifth tooth ;

nasal bones entering the external narial aperture. (Maz-

atlan, Mexico, to Ecuador ; Central America, Cuba, Jamaica,

Haiti, and the southern tip of Florida) . . Crocodylus acutus.

The Field Museum has a small crocodile from Forlon, Tamaulipas,

Mexico, northwest of Tampico, collected by Dr. S. E. Meek in 1903.

This is, apparently, the northernmost known occurrence of crocodiles

on the Gulf Coastal Plain of Mexico. In spite of the difficulty, which

I have stressed above, of distinguishing juvenile specimens of croco-

84 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

diles, I am unable to avoid the conclusion that this specimen is more
nearly allied to moreletii than to acutus. Furthermore, a specimen
from Achotal, Vera Cruz, collected by Heller and Barber, agrees still
more closely with moreletii, both of these Mexican specimens being
short-snouted, with moderately distinct diagonal pre-orbital ridges, a
somewhat better developed dorsal shield, and transverse premaxillo-
maxillary suture. A specimen from Managua, Nicaragua, of similar
size, is plainly acutus, and I believe that acutus is the only form found
on the west coast of Mexico, where crocodiles are abundant as far
north as Mazatlan. I believe, therefore, that Giinther was right in
referring Crocodylus mexicanus from Tampico to C. moreletii, although
Boulenger did not follow him in this conclusion. There is the further
contingency that C. mexicanus may prove to represent a valid northern
subspecies of moreletii, Gadow (Proc. Zool. Soc. London, (2), p.
209, 1905) follows Giinther in giving the range of moreletii as from
Tampico to Honduras (=British Honduras). It seems evident that
much remains to be done to define the range of moreletii and to
determine its interrelations with the range of acutus. It is to be ex-
pected that the distribution of acutus may bear the same relation to
that of moreletii on the mainland as to that of rhombifer in Cuba.

The importance of this form to the genus as a whole, is evident
from what Mook says (loc. cit., p. 199) concerning the primitive
character and relations with fossil forms of C. rhombifer. Crocodylus
moreletii adds a link between the Cuban fauna and that of the mainland
of Central America. The existence of broad-snouted crocodiles, for
the most part small species, in Central America and Cuba, India (C.
palustris), and Central Africa (especially Osteoblepharon osborni),
strongly suggests a case of the radiating dispersal from a northern
center in accordance with Matthew's general theory of dispersal. The
extensive overlapping of the ranges of these smaller forms respectively
by C. acutus in the Americas, C. niloticus in Africa, and C. porosus
in the Oriental region, all extremely vigorous and wide-spread species,
appears to represent a later radial dispersal. This leaves the smaller
and, presumably, more primitive forms with a distribution by no
means peripheral. I believe, however, that restriction of habitat and
of range may frequently take the place of migration in a species re-
treating before the development of a more modern competitor. The
narrow-snouted crocodiles (C. intenncdiits of South America, C. cat-
aphractus of Africa, and C. johnstoni of Australia), appear to rep-
resent parallel forms, adapted to the mechanical requirements of catch-
ing active fish in the water.

MAY, 1924. NOTES ON CENTRAL AMERICAN CROCODILES — SCHMIDT. 85
AMERICAN CROCODILE.

Crocodylus acutus Cuvier.

The American crocodile, Crocodylus acutus, is a much more wide
spread form than the Belize species, and its occurrence in the southern
tip of the Florida peninsula makes it familiar to American herpetolog-
ists. We did not meet this species in British Honduras, but during
our subsequent field work in Honduras, we were fortunate in finding
a location where Crocodylus acutus was abundant, with habitat con-
ditions apparently extremely favorable to crocodilian life.

This was at Lake Ticamaya, a locality to which we were attracted
largely by the advice of Dr. S. M. Waller, of San Pedro Sula. It is
situated about fifteen miles east of San Pedro not far from the Cham-
elecon River, and is a picturesque body of water, its shore-line broken
by deep bays and its surface by numerous islets, some of which are
reefs of bare rock. It is surrounded on all sides, though at varying
distances, by low hills, nowhere more than a few hundred feet high.
The surface of the lake is about a hundred feet above sea level. Its
north and south length is perhaps two miles, while its breadth varies
from about a mile at the widest point, to scarcely a quarter of a mile
at the narrowest, where the water is reduced to two channels of a
hundred yards each by a large island. The water of the lake is
shallow for the most part, with a rather uniform depth (at low
water) of a foot. One of the channels at the island above mentioned
and the central part of the largest bay are the deepest parts, but even
these holes are probably nowhere more than five feet deep. The
bottom is covered with a soft ooze of decayed vegetation, but beneath
this there is a firm bottom, and many parts of the shore line are
gravelly or rocky. The heads of the bays and the shallower western
shore of the lake are fringed with cat-tails. Where the shore is rocky
there is a well defined beach, which may be due to the variation in
level of the water in the wet and dry seasons. At the time of our
arrival, the first week in April, at the height of an unusually rainless
dry season, the water was already low, and during our stay of three
weeks, it fell nearly a foot to the low-water mark.

Perhaps the most extraordinary characteristic of the lake is the
green color and opacity of the water, apparently due to suspended
microscopic algae. The extremely soft mud of the bottom, probably
formed by this plant life, gives off marsh gas during the day, which
rises to the surface and forms a bubbly scum that drifts before the
wind, covering half the lake by the end of the day, to disappear, in

86 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

part, during the night. In the bays and on the lee shores this scum
gathers into thick and permanent crusts on which the jacanas walk.
Small fishes, jumping to escape a passing crocodile or turtle, have
difficulty in breaking through it to return to the water. In the bays,
the crust of algae acquires varied colors, browns, pinks and greens,
often in regular succession from the shores.

The lake is very little above the level of the Chamelecon River,
into which it drains during high water. Old shore lines show that it
must formerly have had a considerably greater extent, the advancing
shore-lines being marked by cat-tail near the water, with Mimosa and
Cassia as the most characteristic elements of the low, shrubby vegeta-
tion behind them. On the higher shores are Cohune Palm and vine
clad hardwoods, among which an occasional gigantic Silk-cotton Tree
is conspicuous. The general area of low and apparently ancient hills
in which the lake is situated, contains a number of other lakes, some
of which are in the last stages of conversion into broad and uniform
expanses of cat-tail marsh. These lakes are very different in origin
and appearance from the oxbow lakes along the river.

The reptiles associated with Lake Ticamaya, other than crocodiles,
were rather few in species. Iguanas and basiliscs were occasionally
seen, but almost invariably escaped into the bushes. One iguana,
started on the large island, dashed into the water, and the wild haste
with which he crossed the strait to the mainland suggested that the
crocodiles had long since disposed of the more aquatically inclined
iguanas. Bascilicus was never seen taking to the water. Three species
of turtles, at least, occur in the lake. A specimen of Kinosternon, too
much decomposed for preservation, was seen on the lake shore; a dry
shell of the Central American snapping turtle (Chelydra rossignonii)
was found near the lake, and a species of Pseudemys was extremely
abundant in the lake. Logs or rocks which were favorite sunning
places of the latter form, were often crowded with individuals to such
a degree that the last possible foothold was occupied. One or two
specimens were caught by setting double spring steel traps on these logs.

Two species of frogs are abundant on the lake shore, the spotted
frog (Rana austricola) and Leptodactyhis melanonotus. Occasional
specimens of Bufo valliceps and Bufo marinus were seen near the lake.

The bird life of the lake is abundant and varied. Several flocks
of cormorants and snake-birds, roosting on the low trees of some of
the islets, fish in groups on its surface. Ducks, chiefly blue-winged
teal, are numerous in the shallow cat-tail fringed bays. Jacanas walk
everywhere along the shores, running well out on the hardened crust

MAY, 1924. NOTES ON CENTRAL AMERICAN CROCODILES — SCHMIDT. 87

of algal scum. Herons, egrets and Tiger Bitterns stand motionless
in the shallow water. The small boat-billed heron is frequently seen.
Rails and sandpipers frequent the vegetation of the shores.

So numerous a bird population, together with the great numbers of
turtles and crocodiles, indicates a great number of fish as their principal
food supply. Small fish jump out everywhere in advance of the canoe,
or of passing turtles and crocodiles. A top-minnow, a small sardine-
like characin, and one or two small species of cichlids were the only
fishes collected, and these were the casual specimens which jumped into
the canoe on being frightened by the paddle.

Crocodiles are extremely numerous in Lake Ticamaya, though very
shy. With a binocular, Mr. Walters was able to count seventy-five
heads of crocodiles in sight at once, in a single bay. At night, on
almost any sector of the shore, thirty to thirty-five eyes could be dis-
tinguished within the range of the head-light. The larger specimens
confined themselves chiefly to the two deeper parts of the lake and
when hunted in one place, could be counted on to appear at the other
on the following day. In marked contrast with the situation at Belize,
there was a total absence, apparently, of small specimens under three
feet in length. At any rate, none were found or seen with the light.
Nor was there a great number of very large specimens, though we
had no difficulty in securing four which exceeded ten feet in length.

The demand for crocodile skins is not continuous in Honduras,
and at the time of our visit, they were not being actively hunted.
The lake, however, attracts a good many duck-hunters, and many of
these take casual shots at the crocodiles, sometimes taking a section
of the skull, chopped out with the machete, as a souvenir. Many
skulls and parts of skeletons are to be found on the lake shore. The
largest skull found measured twenty inches in length. The largest
specimen secured by us measured eleven feet and two inches; its
skull measuring twenty and five eighths inches from snout to occiput,
or .15 of the total. It does not appear, therefore, that the crocodiles
of iLake Ticamaya reach a length of more than twelve feet. The
largest skull we saw (in the possession of Dr. Waller at San Pedro),
measured slightly more than twenty-two inches in length. It is scarcely
necessary to add that these lengths are much increased in reports cur-
rent at San Pedro. As a typical example of exaggeration, a specimen
shot by an American hunter on the day of our arrival was reported
to us as being twelve feet long, while in San Pedro it reached a length
of thirteen feet. Actual measurement of the specimen, on the follow-
ing day, gave it a length of eight feet and ten inches. Much larger

88 FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

specimens of this crocodile are reported from various parts of Central
America, the maximum record know;n to me being twenty-three feet.

The considerable amount of shooting and pursuit to which they
are subjected makes the crocodiles of Lake Ticamaya very shy. It is
difficult to approach within a hundred yards of a specimen on the bank
in daylight. A good pair of field glasses is, therefore, a necessity for
making detailed observations of their positions. A blind on the shore
at the deepest part of the lake proved a very successful aid to ob-
servation. This we constructed very simply by adding to the natural
screen of vines and bushes at the lake shore, clearing out a place be-
hind it, and a path to it from the rear. Plate IX, fig. i is a photograph
from this blind. We frequently surprised a group of crocodiles sunning
themselves on the bank, on rounding a point, and enjoyed seeing their
rush for the water. The quickness of their motions is surprising, and
still more so, the height at which the body is carried. A walking alligator
carries itself clear of the ground, with the hips very slightly higher
than the shoulders. In the crocodiles (with reference to C. acutus),
the hips are notably higher than the shoulders, particularly, when the
animal rises to its feet and walks deliberately. The instant comparison
that comes to the mind of an observer is with the familiar restorations
of the quadrupedal dinosaurs. We did not see crocodiles piled one upon
another as alligators so frequently are in captivity. When lying on
the bank, the head is frequently held free from the ground, often with
the mouth wide open.

The singular habitat conditions of Lake Ticamaya, apparently
favorable to crocodilian life, determine the method of hunting them
in use by the native Carib hunters. The ooze of the bottom gives off
marsh-gas at the slightest touch, and a slowly moving submerged
crocodile can be followed by means of the tracks of persistent bubbles
which register every footprint of the hind feet on the surface above
him. When frightened, he darts off at high speed, leaving a uniform
trail of bubbles called his "pump" by the resident Caribs. A fair
estimate of the size of the crocodile can be made from breadth of
his trail of bubbles. Given this means of following, it is possible to
capture them by harpooning. We found the harpoons of native design
very effective. The points are forged from a short piece of three cornered
file, with one or two barbs on each corner, set in the end of a slender
pole and held in place by the rope which is separately attached to the
point and made fast to the shaft by a hitch at the upper end. About a
hundred feet of three-eighths inch manila rope proved to be ample for
the purpose. One native, living near the lake, enjoyed considerable

MAY, 1924. NOTES ON CENTRAL AMERICAN CROCODILES — SCHMIDT. 89

reputation as a crocodile hunter and appeared, in fact, to be the only
person in the whole San Pedro Valley who had any skill or experience
in harpooning. We employed him to collect our first crocodiles, but
soon learned that we could do nearly as well as the natives ourselves.
Provided with harpoon, .22 rifle, .30 calibre Winchester, in case
of trouble, and single paddles, we set out in a dug-out canoe as early
as possible in the morning. At about eleven in the forenoon, the
wind rises and makes it difficult to follow the trails as well as to
manage the canoe with the harpooner standing in front. The round-
bottomed native dug-outs are by no means easy to handle. A double
paddle would be extremely useful, once the hunt is under way. Arriv-
ing at the upper bay, there is no difficulty in finding a fresh crocodile
trail. As soon as the crocodile finds that he is being pursued, it re-
quires the attention of both paddler and harpooner to keep to the
trail, for the hunted crocodile doubles and turns, and the paddles
leave swirls of bubbles in which his trail is indistinguishable. When
the crocodile takes a straight course, the harpooner tries to judge his
position under water and makes a trial cast of the harpoon, usually
with no other effect than to make him turn off or double back on his
trail. Even a direct hit may fail to take effect if one strikes the head
or one of the bony plates of the back. After a few minutes of pursuit,
the crocodile attempts to hide by coming to a stop on the bottom.
This offers the crocodile his best chance of escape, for if he persists
in sulking and does not happen to be located promptly, it is soon im-
possible to find him at all. We therefore strike into the water with
harpoon shaft and paddle, prodding the bottom and making as much
noise as possible in the water. There is some danger of an upset at
this stage, for when the crocodile is struck or frightened, he creates
a violent commotion in starting out. In fifteen or twenty minutes the
crocodile is compelled to come to the surface for air, but exposes only
the tip of his nose. At some stage of the pursuit, the crocodile nearly
always begins to circle, gradually narrowing the diameter of his course
as he is followed, until he is turning almost in his own length, where-
upon he comes to a stop on the bottom, and must be started again by
prodding with the harpoon or paddle. If, however, he is persistently
followed, in a few minutes more he comes to the surface and swims
with his head out, apparently giving up the under water tactics. When
this occurs, it is of course only a matter of a few minutes until the
harpoon is fast in the crocodile's back. At this he submerges again and
the harpooner recovers the harpoon shaft and then hastens to pay out

QO FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

rope, as it is dangerous to tempt a large crocodile by remaining too
close to him while pulling on the rope.

Landing the crocodile is still a matter of some difficulty. Specimens
over ten feet in length could not be towed with the canoe. One of us,
therefore, stripped and waded in the breast-deep water, hauling steadily
on the long rope. With a long rope, even the largest specimens we
secured were rather easily managed in this way. The unfortunate
beast makes a few struggles, rushing about at the surface of the water
with open jaws, but it is surprising that so powerful an animal makes
so little effectual resistance. It is important to choose a rocky shore
on which to beach the crocodile as he may otherwise become deeply
buried in the mud.

Once hauled out, a large crocodile is a savage customer, snapping
viciously at his captors and at the rope. The largest specimen which
Mr. Walters and I secured alone, snapped at the bullet that killed him,
the jaws making a report very much like that of the .22 rifle. Our
first specimens we shot in the water with the .30 calibre Winchester,
but we presently found it was quite simple to manoeuvre into position
and despatch them by shooting vertically into the neck, at the base of
the skull, with the .22 rifle. This shot not only does not damage the
skull, but has the advantage of killing the animal with a minimum of
reflexes left in the body.

The skinning by natives is crudely done, largely with the
machete. The whole skin is used in the smaller specimens, up to six
or seven feet in length, but in the larger ones only the belly, sides,
legs and the base of the tail are skinned, the bony plates of the back
being too thick, at any rate for the native tanners. For our purpose,
skinning required much more care and thoroughness than any
native would give it, and we did this ourselves. In addition to
skins, we made three complete and several partial plaster molds.

In waters less favorable to crocodile hunting than Lake Tica-
maya, other methods than the one described must be employed.
The use of a baited set line, and hunting from a blind with a
tethered bait are well-known methods of hunting, especially for
solitary individuals whose location is more or less permanent. By
far the most practicable method is night shooting. We spent
several nights on the lake equipped with carbide head-lights, rifle
and harpoon. At night on Lake Ticamaya, with the head-light,
one sees crocodile eyes on every hand. Their fiery red reflections
may be seen from every angle, even from the rear. One very rarely

MAY, 1924. NOTES ON CENTRAL AMERICAN CROCODILES — SCHMIDT. 91

sees both eyes, and for an estimate of the size of the animal, it is
usually necessary to depend upon the apparent size of the eye,
which is not a very reliable guide. One can usually approach closely
enough, however, to see the outline of the head, though rarely
near enough to use the harpoon, except on the smaller specimens.
We secured several four and five foot specimens alive in this way,
but did not attempt to capture any large ones. We once had a
narrow escape from upsetting the dug-out when we ran full onto
the back of a good sized crocodile, near shore, where he had sub-
merged to evade our pursuit. In shooting, it is necessary that the
animal be killed outright, and even then it may be difficult to locate
the body which usually appears at the surface only once.

The food of the smaller specimens doubtless consists, almost
exclusively, of small fish. One stomach examined contained the
remains of eight top-minnows, together with the handful of small
stones which are to be found in every crocodile stomach, whether
otherwise empty or not. The diet of the larger specimens is more
varied. Mr. Walters observed a large crocodile whirling what ap-
peared to be a smaller one in the air, as is the habit of crocodilians
in tearing apart larger prey. We found a turtle in the lake which
had been cut in two, apparently, by the bite of a large crocodile.
That the larger crocodiles eat both the young of their own species
and turtles, was confirmed by finding horny plates of turtle shell
and the vertebrae and several limb bones of a four or five foot
crocodile in the stomach of a ten foot specimen. This stomach also
contained a hair ball and the horny hoofs of (probably) a peccary.
Another ten foot specimen had only two small fish in its stomach,
and several stomachs were entirely empty except for the stomach
stones.

At the time of our leaving the lake, the crocodiles were begin-
ning to lay their eggs. We found a single nest containing fresh
eggs, on the shelving gravel beach of the largest island. The nest
was situated in an open space a few yards broad, between the sedge
and water plants at the water's edge and the abrupt screen of vines
which marks the higher ground. The position of the nest was
indicated by a small amount of fresh gravel about a foot away
from the edge of the nest. Above the nest, the gravel was in
every way uniform with the surrounding surface except for its
looseness. There was no fresh gravel at the top of the nest itself.
Some of the stones in the gravel are three to five inches in diameter.

pa FIELD MUSEUM OF NATURAL HISTORY — ZOOLOGY, VOL. XII.

When dug out, the upper layer of eggs was found to be about eight
inches below the surface. The total depth of the hole was twelve
inches. The diameter at the top was about sixteen inches, at the
bottom about twelve inches. The twenty-two eggs were in two
layers without regular arrangement. The nesting site and a set of
eggs are shown in Plate IX, figures 2 and 3. The largest and
smallest eggs measure, respectively, 76x45.5 mm. and 70x42 mm. The
shape is a uniform oval. The shell is hard and rather strong, its
surface porcelain-like. It may be nearly smooth, or rugose and pitted.
We tested their edibility and found that, beyond a slight toughness,
there was scarcely any appreciable difference between them and ordinary
hens' eggs. The natives assured us that they were entirely inedible,
with a strong and disagreeable flavor.

The egg-laying habits of Crocodylus acutus thus form a close par-
allel to those of C. niloticus. Barbour, quoting Gundlach, gives a
similar habit for C. rhombifer. It appears that the crocodiles are
rather well distinguished in their egg-laying from the American
Alligator and some of the Caimans, which build a considerable "nest"
of plant material in which the eggs are deposited. Life histories thus
lend support to the taxonomic arrangement. Accounts of the egg-
laying of other species of crocodiles, of the various species of Jacare
and Caiman, and especially of the Chinese Alligator, would be of great
interest in reenforcing or refuting this evidence of relationship.

In the interior of Honduras, crocodiles are rather local in their
distribution. We saw specimens at Lake Yojoa, at two thousand feet
above sea level, and specimens were reported from the Rio Verdugo,
emptying into the Gulf of Fonseca, on the Pacific side. In the rivers,
large specimens frequently take up residence in a hole, where they
apparently live a solitary life. Crocodiles were formerly numerous at
Puerto Cortes, and they probably abound in the brackish lagoons along
the northern coast.

A study of geographical variation in this species of crocodile may
be expected to prove highly interesting. It is a variable form, the
characteristic hump on the nose being often absent. The distribution,
extending northward on both coasts of Mexico, southward to South
America, and through Cuba, Jamaica and Haiti to the southern tip of
Florida, is by no means well defined. Barbour (Herpetology of Cuba)
has shown its peculiar habitat and distributional relations with Croc-
odylus rhombifer in Cuba. The relations with C. moreletii in these
respects are unknown, except that we found no Crocodylus acutus at
Belize, in the same waters with C. moreletii.

THE UBHA81 Of IHE
JUL 1 ' 1924

iwlVERSlTY OF ILLINOIS

FIELD MUSEUM OF NATURAL HISTORY.

ZOOLOGY, VOL. XII, PL. VI.

FIG. 1. DORSAL VIEWS OF SKULL OF Crocodylus moreletii (RIGHT) AND C. acutus

(LEFT), FIELD MUSEUM Nos. 4430 AND 5775, x .48.
FIG. 2. LATERAL VIEW OF SKULL OF C. moreletii, FIELD MUSEUM No. 4430, x .45.

FIELD MUSEUM OF NATURAL HISTORY. ZOOLOGY, VOL. XII, PL. VII.

DORSAL VIEW OF SKULL OF C. moreletii, FIELD MUSEUM No. 4430.
X .65.

ntlYERSITY OF ILLINOIS LIBBAB'

FIELD MUSEUM OF NATURAL HISTORY. ZOOLOGY, VOL. XII, PL. VIII.

PALATAL VIEW OF SKULL OF C. moreletii, FIELD MUSEUM No. 4430.

X .65.

FIELD MUSEUM OF NATURAL HISTORY.

ZOOLOGY, VOL. XII, PL. IX.

FIG. 1. VIEW OF LAKE TICAMAYA, WITH CROCODILES SUNNING THEMSELVES ON THE
DISTANT SHORE, AND THE HEAD OF A SUBMERGED CROCODILE IN THE FOREGROUND.
TAKEN FROM A BLIND.

FIG. 2. NESTING SITE OF Crocodylus acutus AT LAKE TICAMAYA. THE SAME SHORE
AS SHOWN ABOVE WITH THE CROCODILES.

FIG. 3. NEAR VIEW OF THE EGGS AND NEST OF Crocodylus acutus, TO SHOW THE
DEPTH OF THE HOLE AND CHARACTER OF THE SOIL.

UNIVERSITY OF ILLINOIS-URBANA