American Alligator
Dinosaurs
still walk the earth in Oklahoma. Southeast Oklahoma to be exact
and they swim more often than they walk. Remaining unchanged for
65 million years, the American alligator is Oklahoma’s
representative from the Triassic period. They are actually more
closely related to birds, which are direct descendants of
dinosaurs, than they are to modern reptiles like lizards.
Fully grown male alligators typically reach 13 to 15 feet and
females reach lengths of just under 10 feet. Adults tend to be a
grayish-black in color with lighter colored bellies. The young
can be more colorful with yellow or white highlights. The whole
body is armored with large, bony plates. Eyes, ears and nostrils
are near the top of the head, with valves to close the ears and
nostrils when the alligator is submerged. A transparent eyelid
allows them to see underwater. While they move with serpentine
grace in water, they are less graceful on land. They either
lumber along, or raise themselves off the ground and move at
speeds up to 20 miles per hour for a short distance.
Their large, strong mouths have 80 teeth, and are used to
capture, crush and dismember their prey. Alligators cannot chew,
so they swallow their food whole or in chunks. They often lose
teeth in encounters with prey but they are quickly replaced.
Each tooth contains a small replacement tooth within its pulp
cavity and examination sometimes reveals a further tiny tooth
ready to erupt within that.
The American alligator’s breeding season usually begins around
May and lasts for six to eight weeks. They mate underwater
during the last several days of their courtship season. Females
construct the nests in June and July on mounds of high banks.
The construction of the nest provides a constant temperature for
the 20-30 eggs so that the female doesn’t have to sit on the
nest like her avian cousins.
Sex of the hatchlings is determined by the temperature of the
eggs during incubation. Temperatures greater than 91 degrees
produce males, temperatures less than 85 degrees produce females
and temperatures in between produce both sexes. Hatching occurs
in mid-August after about 65 days of incubation. When the
hatchlings break out of their eggs, they make a distinctive call
and the female digs up the eggs. Female alligators are very
protective of their offspring, which may stay near her for more
than two years. They are very vulnerable to predation by
raccoons, otters, herons, snakes, fish, bullfrogs and other
alligators.
Juveniles eat a wide variety of small invertebrates,
particularly insects, and small fish and frogs. As they grow
larger, their diet increases to include larger prey. Eventually,
large adults can tackle nearly all aquatic and terrestrial prey
that comes within range, although their diet mostly includes
fish, turtles, small mammals, and birds.
Alligators can often be found basking with just their eyes,
nostrils and snouts above the water primarily in freshwater
swamps and marshes, but also in rivers, lakes and smaller bodies
of water. In Oklahoma they are found in Red Slough Wildlife
Management Areas and the Little River National Wildlife Refuge.
Though they have been found in other counties, Choctaw County
and McCurtain County claim the highest number of the scaly
predators. It is unlikely that they could survive the winter any
further north.
Alligators hibernate in burrows, also known as “alligator
holes,” when the average temperature falls below 75 degrees.
Even outside their burrows, however, they can tolerate limited
periods of freezing conditions. Known as the “icing response,”
they submerge their body but keep their nostrils projecting
above the water surface, so that when the surface freezes they
can still breathe. Essentially their upper body becomes trapped
in the ice.
Anyone who wants a chance to see walking, or swimming, history
can make a trip to the southeast corner of Oklahoma on a warm
summer day. Though rarely glimpsed, you just might see
Oklahoma’s resident dinosaurs basking lazily in the sun.