Order: Testudines
Family: Chelydridae
Macroclemys temminckii (Alligator Snapping Turtle)
Written by Toby Turtle, Georgia Natural History student (2002); Editor OK
Geographical Distribution- The
alligator snapper can be found in sw.
Georgia and n. Florida, west to e.
Texas and northward in the
Mississippi Valley to Illinois and
Indiana. Alligator snappers can be
found in almost every river system
from Florida to e. Texas.
Physical Characteristics- The very
large head, three-keeled carapace,
and extra marginal scutes of the
alligator snapper are its most
diagnostic features. Carapace lengths of adult alligator snappers range from about 38 to 80
cm and individuals over 300 lbs. have been recorded. Sexual dimorphism is pronounced
with males attaining larger overall size. The shell ranges from light brown to black and the
dark brown skin is covered with pronounced scales called tubercles. The tail is very long
and is crested by saw-toothed scales. Often the skin and shell of the turtle are covered with
algae. The young (3-4.5 cm at hatching) have a rough textured shell.
Habitat- Alligator snappers can be found in the deeper waters of large rivers, creeks, lakes,
and swampy backwaters. Areas with abundant aquatic vegetation, a soft substrate, and
emergent trees and stumps are preferred. They can also be found in brackish water.
Food Habits- Alligator snapping turtles are primarily piscivorous (fish-eaters). However, a
wide variety of vertebrate and invertebrate prey have been found in stomach analyses. In
addition, plant material is frequently consumed including acorns and aquatic macrophytes.
Alligator snappers are also fond of
carrion.
Behavior- Alligator snappers are almost
completely aquatic and rarely venture
onto land except to lay eggs. They actively forage and scavenge at night. By day, they tend
to remain motionless on the bottom where they ambush fish and other aquatic vertebrates.
To lure fish, alligator snappers wiggle a worm-like lure inside the bottom jaw. When the fish
attempt to eat the “worm” the turtles snap their jaw closed, severing the fish or impaling it on
its sharply hooked jaws. Upon capture, they keep their mouth open and will clamp onto
anything that happens to pass between their jaws
Reproduction- Alligator snappers probably reach maturity between 11 and 13 years.
Observations of copulating pairs indicate that alligator snappers mate primarily during
spring. Females deposit their eggs in well-drained soils within about 50 meters of water. The
clutch size varies in accordance with female size and the number of eggs is generally
between 8 and 52. The gender of hatchlings is determined by the incubation temperature
with females produced at intermediate temperatures and males produced at either extreme.
Conservation- Throughout its range the alligator snapping turtle is threatened by habitat
alteration, overcollection of adults for food, and pollution. Population studies suggest that
the species undergoing a decline from its historically low densities in southeastern rivers
and streams. Take (trapping, capture of turtles) is prohibited in Arkansas, Florida, Georgia,
Indiana, Missouri, Tennessee. Take is allowed with the necessary permit in Alabama,
Illinois, Kansas, Louisiana, Oklahoma and Texas.
References and Photograph CreditsPeterson Field Guide to Reptiles and Amphibians. Conant and Collins. Third Edition. 1991.
Turtles of the United States and Canada. Ernst, Lovich, and Barbour. Smithsonian
Institution Press. 1994
http://www.redlist.org/ - The 2000 IUCN Red List of Threatened Species
http://animaldiversity.ummz.umich.edu/index.html - The University of Michigan Museum of
Zoology Animal Diversity Website.
http://www.qamla.com/ - Qualma Zoo’s website (first photograph).
http://www.bigwoods.net/ - Bigwoods on The Trinity website (second photograph).