Albert Moore Reese.

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a hole that the nest is built, as will be described
later.

Often from a small swamp or slough alligator
"trails" lead off in different directions. These
trails are narrow, winding gullies such as might be
made by cattle in a damp pasture. If followed
from the main slough the trail will usually be
found to end in a "hole," in which an alligator will
probably be found (Fig. 7). In a great swamp like
the Everglades or the Okefinokee such holes would
naturally not be fotmd.

On one side of the hole is usually a smooth place
where the vegetation is worn away; it is here that
the 'gator "pulls out" to sleep in the sun; and
wary must the hunter be to approach within sight



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12 The Alligator and Its Allies

of the animal before being seen or heard by him.
At the first alarm he slides quietly or plunges
quickly into the muddy water, and the hunter
must wait long if he expects to see the 'gator come
to the surface.

The opening of the cave is always below the
surface of the water, but it is possible that there
may be a subterranean chamber that is not com-
pletely filled with water. How the animal is
gotten from his cave will be described later. Ac-
cording to some writers the alligator retires to his
cave to hibernate during the cooler winter months.
This is possibly true in the more northerly limits
of his range. It is well known that if kept in cool
water the alligator will lie dormant and refuse all
food for months at a time. The writer has had
young alligators in captivity, under these condi-
tions, that refused food from late in the auttmm
until nearly the first of April.

The proprietor of one of the largest alligator
farms in the country ^says: ''Otu: alligators stop
eating the first week in October and do not begin
to eat until the latter part of April. We have
experimented with our stock to see if we could get
them to eat in the winter, and found that by keep-
ing the water in the tanks at a certain temperatture
they would eat, but we found out that the warm
water would make their bowels move, and that
they would not eat enough to keep themselves up,
as in the stmimer, and as a result they would be-



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The Biology of the CrocodiHa 13

come very poor and thin, so we do not force them
to eat any more." The effect upon the growth
of an animal of these two methods of feeding will
be noted later when the age and rate of growth are
discussed. The same writer says, in answer to a
question about hibernation: ''In their wild state
they go into their dens under water and remain
dormant all winter." Whether this statement is
the result of actual observation the writer is not
able to say, but, judging by some other statements
from the same source, it is probably from hear-
say. The writer, having visited the alligator haunts
only in late spring and stmimer, has had no oppor-
tunity of studyinjg the habits of the animal in its
natural habitat during the winter season. During
the heat of stimmer the animal does not seek the
sun as he is said to do during cooler weather, but
spends more time on the bank at night and during
the cooler parts of the day.

That he sometimes wanders over dry land, per-
haps going from hole to hole, is evident from the
tracks that are sometimes seen crossing a dusty
road or path. These trails are easily recognized
by the clawed footprints with a line, made by
the dragging tail, between them. Although most
awkward on land, he can, if necessary, move very
quickly. It is, however, in the water that he
shows to best advantage; he is an active, power-
ful swinmier, his tail being used as a propeller as
in the fishes. When swimming actively the legs



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14 The Alligator and Its Allies

are held close against the bcxiy in order that they
may retard the animal's motion as little as possible.
While swimming in a leistirely way the top of the
head is at the surface of the water, perhaps just
the nostrils and eyes projecting above the surface,
so that the size of the animal can be estimated by
the distance between these projecting points. One
afternoon the writer and a guide, while paddling
along an old canal that was dug years ago into
the Okefinokee Swamp, were preceded for perhaps
half a mile by a large alligator that swam just fast
enough to keep out of otu: reach until he came to the
place where he wanted to turn off into the swamp.

Although so awkward on land, the alligator is
said to be able to defend himself very effectively
with his tail, which he sweeps from side to side
with sufficient force, in the case of a large specimen,
to knock a man off his feet. Although the writer
has seen captured and helped to capture alive
several alligators up to eight feet in length he has
never seen this vigorous use of the tail as a weapon
of defense.

While the alligator, like most other wild animals,
will doubtless defend itself when cornered, it will
always flee from man if possible, and the writer
has frequently waded and swam in ponds and lakes
where alligators lived without the least fear of
attack. This might not have been possible years
ago when the animals were more numerous and
had not been intimidated by man and his weapons.



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The Biology of the Crocodilia 15

Food. The food of the adult alligator consists
of fishes, birds, mammals, and possibly smaller
individuals of its own species. The young eat
small fish, frogs, insects, or worms.

If the animal be too large to swallow whole it
is shaken, and torn, the shaking being so vigorous
that, according to Ditmars, the entrails of the
prey may be thrown to a distance of twenty feet
or more. Should two alligators seize the same
prey at the same time they whirl about in opposite
directions so violently that the prey is torn apart.
This action may be illustrated by giving two small
captive alligators a piece of tough meat; they hold
on with bulldog tenacity, and each, folding its legs
close to its body, will use its tail like a propeller
until the animal whirls around with remarkable
speed. The commotion that two ten-foot alli-
gators would cause when thus struggling can easily
be imagined. That a large alligator, if it tried,
could easily drag under the water and drown a man
or possibly a much larger animal is evident.

While the alligator has a valve-like fold of skin
in its throat that enables it to open its mouth and
crush its prey under water, it is said that it must
raise its head above water in order to swallow
its food. A young alligator on land will usually
throw back its head when trying to swallow a
large piece of meat, so that it may be simply this
motion that brings the head of the alligator above
the surface of the water.



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i6 The Alligator and Its Allies

Ditmars thus describes the fate of a dog that
approached too near a very large alligator: "As
a dog, weighing about fifty pounds, unwarily ap-
proached the edge of this creatture's tank, it was
suddenly grasped and before completing its first
yelp of terror was dragged beneath the surface. A
few minutes later the twelve-foot saurian appeared
at the top, holding the dead canine in its jaws.
The dog was shifted about, amid the sotmd of
breaking bones, and swallowed head first, and
entire, after a few gulps."

Size and Growth. Although, years ago, alligators
of fifteen feet length may have been common in
favorable localities in the South, it is probable
that few if any such monsters now exist. A
twelve-foot alligator, owing to its great girth, is a
huge animal and but few of this size are to be
found in captivity. The largest specimen the
writer has ever seen is the one in the Bronx
Zoo, which is barely thirteen feet in length. At
hatching the alligator is about eight inches in
length.

Clarke (17) says: "The largest specimen I saw
measured twelve feet in length; and none of the
many htmters and natives of Florida I have met
have seen any longer than thirteen feet. All the
hunters agree that it is only the males that acquire
the great size; no one had ever seen a female that
meastured over eight feet, and the majority are not
over seven. The male has a heavier, more power-



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The Biology of the Crocodilia 17

fill head, and during the breeding season especially
is more brilliantly colored."

It is a very common belief, even among those
who should be most familiar with their habits,
that the growth of the alligator is remarkably slow,
so that a large specimen may be described by the
exhibitor as more than a century old. The same
dealer in alligators quoted above says upon this
subject: "You can figure about two inches a year
to their growth." He also says: "We judge that
an alligator about twenty-five to thirty years old
will breed." Even scientific writers of reputation
have not been free from this error in their writings.
That the alligator may live to an extreme age, as
seems to be true of some of the tortoises, is quite pos-
sible, and it is probable that after reaching a length
of twelve or fifteen feet the growth is very slow.

In captivity, when kept in warm water and
other favorable conditions, the alligator will grow,
according to measurements taken at the New York
Zoological Park, at the rate of about one foot a
year, for about the first ten years. Under unfavor-
able conditions the growth may be exceedingly
slow. Under favorable conditions in nature the
rate of growth may exceed that given above.

Instead of requiring twenty-five to thirty years
to reach sexual maturity, as quoted above, it is
likely that the female may lay eggs at five to ten
years, though such a fact is difficult to determine
of animals in their native haunts.



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i8 The Alligator and Its Allies

Voice. The alligator, unlike most other members
of its class, the Ophidia, Chelonia, and Lacertilia,
has a voice, which, in an adult bull, may be heard
for a mile or more. This bellowing is difficult to de-
scribe; it is something between a moan and a roar,
and may be to attract the opposite sex or to serve
as a challenge to other large animals. It is usually
ascribed to the male, but whether confined to him
or not the writer is unable to say.

In younger animals the voice is, of cotirse, less
deep and in very young individuals it is a squeak
or grunt, easily imitated by hunters for the purpose
of luring the animals from their hiding places.

Breeding Habits. Judging from the statements
of native hunters the laying season of the alligator
might be thought to be at any time from January
to September. As a matter of fact the month of
June is the time when most, if not all, of the eggs
are laid. S. F. Clarke gives June 9th and June
17th as the limits of the laying season in Florida,
but I found at least one nest in which eggs were
laid as late as Jtme 26th: no eggs were foimd before
the first date given by Clarke. It seemed quite
certain that the laying, during the season in ques-
tion, had been delayed by an extreme drought that
had dried up the smaller swamps and reduced the
alligator holes to mere puddles. Nests were foimd
in considerable numbers as early as Jtme 8th, but no
eggs were laid in any of them until the end of the
dry period which occurred nearly two weeks later.



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The Biology of the Crocodilia 19

Almost immediately after the occurrence of the rains
that filled up the swamps eggs were deposited in all
of the nests at about the same time. From the fact
that all of these completed nests had stood for so
long a time without eggs, and from the fact that
all of the eggs from these nests contained embryos
in a well-advanced state of development, it seemed
evident that the egg-laying had been delayed by the
unusually dry weather. Eggs taken directly from
the oviducts of an alligator that was killed at this
time also contained embryos that had already
passed through the earlier stages of development.
Thus it was that the earliest stages of development
were not obtained during this sunmier.

It is said that dtiring the mating season, which
precedes by some time, of course, the lajdng season,
the males are noisy and quarrelsome, and that
they exhibit sexual characteristics of color by
which they may be distinguished from the females.
Never having been in the alligator country at this
season, the writer has made no personal observa-
tions along these lines, but from the frequency
with which alligators with mutilated or missing
members are found it is evident that fierce encoim-
ters must sometimes take place, whatever the
cause. During Jime and July, at least, and prob-
ably during most of the year, the alligators are
very silent, an occasional bellow during the very
early morning hours being the only audible evi-
dence that one has that the big reptiles are in the



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20 The Alligator and Its Allies

neighborhood. Whatever may be the sexual differ-
ences during the mating season, at ordinary times
the two sexes are so much alike that I have, on
more than one occasion, seen experienced hunters
disagree as to the supposed sex of an alligator that
had just been killed.

Although I have never seen a nest actually during
the process of construction, it is easy to imagine,
after the examination of a large ntimber of freshly
made nests, what the process must be like.

The alligator, probably the female, as the male,
after the mating season, takes no interest whatever
in the propagation of his species, selects a slight
elevation on or near the bank of the "hole"
in which she lives. This elevation is generally,
though not always, a sunny spot, and is frequently
at the foot of a small tree or cltimp of bushes.
Where the alligator is living in a large swamp she
may have to go a considerable distance to find a
suitable location for her nest; when her hole is
scarcely more than a deep, overgrown puddle, as
is often the case in the less swampy regions, she
may find a good nesting place within a few feet of
her cave. That the female alligator stays in the
neighborhood of her nest after she has filled it
with eggs seems pretty certain, but that she defends
it from the attacks of other animals is extremely
doubtful: certainly man is in very little danger
when he robs the nest of the alligator, and, accord-
ing to the statement of reliable hunters, bears are



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The Biology of the CrocodiHa 21

very persistent searchers for and eaters of alligator
eggs. Having selected (with how much care it
is impossible to say) the location for the nest, the
alligator proceeds to collect, probably biting it
off with her teeth, a great mass of whatever vegeta-
tion happens to be most abundant in that imme-
diate vicinity. This mass of flags or of marsh grass
is piled into a conical or rounded heap and is
packed down by the builder repeatedly crawling
over it.

There is a great deal of variation in the size and
form of the different nests, some being two meters
or more in diameter and nearly a meter in height,
while others are much smaller in diameter and so
low as to seem scarcely more than an accidental
pile of dead vegetation. It is probable that the
nests are under construction for some time, per-
haps to give time for the fresh vegetation of which
they are composed to ferment and soften, and
also for the material to settle into a more compact
mass. The compactness of the alligator's nest
was well illustrated one day when the writer used
an apparently deserted nest as a vantage ground
from which to take a photograph: on opening this
nest it was foimd, after all, to contain eggs, and
though some of the eggs were cracked, none of
them vere badly crushed. This nest although it
was so low and flat that it was thought to be one
that had been used during some previous season,
contained forty-eight eggs, a greater number than



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22 The Alligator and Its Allies

was found in any other nest; while in other nests
that were twice as large as this one were found less
than half as many eggs, showing that there is no
relation between the size of the nest and the number
of eggs. The average nimiber of eggs per nest,
in the twelve nests that were noted, was thirty-one.
One observer reported a nest that contained sixty
eggs, but this, if true, was a very unusual case.
Reports of still larger ntimbers of eggs in one nest
probably refer to crocodiles, which are said to lay
one hundred or more eggs in a nest. Although
crocodiles may be found in certain parts of Florida,
the writer has had no opportunity of observing
their nesting habits.

The eggs are laid in the nest without any apparent
arrangement. After the nest has been prepared,
and has had time to settle properly, the alligator
scrapes off the top, and lays the eggs in a hole
in the damp, decaying vegetation; the top of the
nest is again rounded off, and it is impossible to
tell, without examination, whether the nest con-
tains eggs or not.

As to whether the same nest is used for more
than one season there is a difference of opinion
among alligator hunters, and the writer has had
no opportunity of making personal observations.

While it is usually stated that the eggs are in-
cubated by the heat of the sun, it is held by some
observers that the necessary heat is derived not
from the sun but from the decomposition of the



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Fig. 7. A Typical 'gator " Hole."

Only a few yards across, and surrounded by a dense growth of vegetation. On the
far side is seen an opening in the surrounding grass and flags where the ground is
worn smooth by the alligator in crawling out of the hole. Under the bank, probably
near the place where the alligator "pulls out," is the deep cave into which the in-
habitant of this hole quickly goes on the approach of danger. As this cave may be
fifteen or twenty feet deep it is not an easy matter to get the animal out. When a
female alligator inhabits such a hole, a nest may often be found within three or four
yards of the water, though it is sometimes at a greater distance. Such a hole as this
may be connected by narrow, winding "trails " T\'ith larger ponds, as noted under
Fig. 6. (From a Photograph by the Author.)



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The Biology of the Crocodilia 23

vegetable matter of which the nest is composed.
Possibly heat may be derived from both of these
sources, but it seems likely that the conditions
that are especially favorable to normal incubation
are moisture and an even, though not necessarily
an elevated, temperature. Moisture is certainly
a necessary condition, as the porous shell allows
such rapid evaporation that the egg is soon killed
if allowed to dry. The inside of the nest is always
damp, no matter how dry the outside may become
under the scorching sim, so that this condition is
fully met. The eggs of the Madagascar crocodile,
according to Voeltzkow,' offer a marked contrast
to those of the alligator. Instead of being laid
in damp nests of decaying vegetation, they are
laid in holes that are dug in the dry sand, and are
very sensitive to moisttire, the early stages, espe-
cially, being soon killed by the least dampness. A
crocodile's nest containing eggs is shown in Figure
5. In this species of crocodile, probably C. porosus,
the nest resembles that of the Florida alligator.
The photograph was taken by Mr. Rowley on the
edge of a small lake on the Island of Palawan, P. I.
The daily range of temperattire in the Southern
swamps is sometimes remarkably great, so that if
the eggs were not protected in some way they would
often pass through a range of temperature of pos-

' Vodtzkow, A., "The Biology and Development of the Outer Form
of the Madagascar Crocodile," Abhandl, Senckherg. Gesell., Bd. 26,
Hft.I,



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24 The Alligator and Its Allies

sibly fifty degrees or more; while in the center of a
great mass of damp vegetation they are probably
kept at a fairly constant temperatiire. Unfortu-
nately no thermometer was taken to the swamps,
so that no records of the temperatures of alligator
nests were obtained, but it was frequently noticed
that when, at night or very early in the morning,
the hand was thrust deep into the center of an
alligator's nest the vegetation felt decidedly warm,
while in the middle of the day, when the surroimd-
ing air was, perhaps, fifty degrees (Fahrenheit)
warmer than it was just before simrise, the inside
of the same nest felt quite cool. It is probable,
then, that the conditions of temperature and
moisture in the center of the nest are quite uniform.
One lot of eggs that had been sent from Florida to
Maryland continued to incubate in an apparently
normal way when packed in a box of damp saw-
dust, the temperature of which was about 80 de-
grees Fahrenheit. Another lot of eggs continued
to incubate, until several young alligators were
hatched, in the ordinary incubator, at a tempera-
ture of about 95 degrees Fahrenheit.'

The fact that eggs taken directly from the ovi-
ducts of the cold-blooded alligator contain embryos
of considerable size seems to indicate that no such
elevation of temperature as is necessary with avian
eggs is necessary with the eggs of the alligator.

' Reese, A. M., "Artificial Incubation of Alligator Eggs," Amer.
Nat., March, 1901, pp. 193-195.



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Fig. 8. A Typical Alligator's Nest, Made Chiefly of Grass.

The guide is feeling for eggs without disturbing the outside of the nest. Being
made of the same material as the background, the nest does not stand out very
sharply, though in nature the contrast is somewhat more marked, owing to the
fact that the surrounding grass is green while the grass of which the nest is built
is dead and brown. (From a Photograph by the Author.)



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The Biology of the Crocodilia 25

The complete process of incubation probably
extends through a period of about eight weeks,
but no accurate observations along this line could
be made. For some hours previous to hatching
the young alligators make a curious squeaking
sound inside the shell, that may be heard for a
distance of several yards: this sound may be for
the purpose of attracting the attention of the female
alligator, who will open the top of the nest in time
to allow the just hatched alligators to escape : unless
thus rescued, it would seem impossible for the little
animals to dig their way out from the center of
the closely packed mass of decaying vegetation.

At the time of hatching the alligator is, as already-
noted, about eight inches in length, and it seems
impossible that it should have been contained in
so small an egg.

The size of alligator eggs, as might be expected,
is subject to considerable variation. In measuring
the eggs a pair of brass calipers was used, and the
long and short diameters of more than four hundred
eggs were obtained. A ntimber of eggs of average
size, when weighed in mass on the scales of a
country store, gave an average of 2.8 oz. per egg.

There was more variation in the long diameter
of eggs than in the short diameter.

The longest egg of all those measured was 85
nmi.; the shortest was 65 mm. The widest egg
(greatest short diameter) was 50 mm.; the nar-
rowest egg (least short diameter) was 38 mm.



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26 The Alligator and Its Allies

The average long diameter was 73.742 mm.; the
average short diameter was 42.588 mm.

The greatest variation in long diameter in any
one nest of eggs was 15.5 mm.; the greatest varia-
tion in short diameter in the eggs of any one nest
was II mm.

The average variation in the long diameter of
the eggs from the same nest was 1 1.3 18 mm.; the
average variation in the short diameter of the
eggs from the same nest was 5.136 mm.

It will be seen from the above that the average
variation in the long diameter of eggs from the
same nest is between one sixth and one seventh of
the long diameter of the average egg; while the
average variation in the short diameter of the eggs
from the same nest is less than one eighth of the
short diameter of the average egg.

S. F. Clarke' gives the limits of the long diameter
as 50 mm. and 90 mm., and the maximtim and
minimum short diameters as 45 mm. and 28 mm.
No such extremes in size were noticed among the
eight hundred or more eggs that were examined.

Economic Importance.^ More than one himdred
years ago attempts were made to utilize the skin


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