Alabama is home to approximately 85 species of native reptiles, including turtles, lizards, snakes, and one species of crocodilian. The state's warm, temperate climate and great variety of aquatic and terrestrial habitats provide homes to reptile species that range in size from the ground skink (Scincella lateralis), at three inches long (seven centimeters), to the Atlantic leatherback sea turtle (Dermochelys coriacea), which at 74 inches long (178 centimeters) and up to 1,200 pounds (544 kilograms) is the world's largest turtle. In addition, four species of exotic lizards may have become established in recent years. Reptiles are an integral and important part of Alabama's ecology.
Reptiles are ectothermic ("cold blooded"), air-breathing, vertebrate animals characterized by amniote (usually shelled) eggs,
scales, claws, and sometimes horns or rattles. Although most lay eggs, some reptiles (including all pit vipers) give birth
to live young. Some reptiles may appear to be shiny, but their waxy skin generally lacks glands and is not moist (as in most
amphibians). Because the body temperatures of reptiles are determined by the temperatures of their surrounding environments, their activities
are largely restricted to the warmer seasons. They frequently bask in the warming rays of the sun to absorb heat, which is
essential for normal activity. Reptiles generally become dormant during cold winter months. But because Alabama's climate
is so moderate, some reptiles may remain active during much of the year, even during warmer periods of the winter months.
Types of Alabama Reptiles
Turtles (Order Chelonia or Testudines)
Alabama has 30 species of turtles, which constitute the most ancient group of reptiles known. Lacking teeth, turtles are characterized by prominent, hard shells that encase most of their bodies, and that are connected directly to their vertebral columns (backbones). Turtles may live on land or in fresh water, salt water, or brackish water. All turtles—even those that are solely aquatic or marine—lay eggs on land in nesting cavities that they dig with their legs. The embryos then develop independently of their parents. Turtles exhibit a wide range of diets: some, such as gopher tortoises (Gopherus polyphemus), are primarily herbivorous; others, such as snapping turtles (Chelydra serpentina), are carnivorous; and still others, such as the Eastern box turtle (Terrapene carolina), are omnivorous. Terrestrial turtles are known as tortoises. Because of their basking habits, turtles are frequently observed in nature. One of the most common aquatic species is the pond slider (Trachemys scripta). The Eastern box turtle (Terrapene carolina), a woodland species, is the most familiar terrestrial turtle. Alabama has three species of aquatic softshell turtles that constitute one of the most distinctive groups. Flat, leathery, pancake-shaped and devoid of any scales, softshell turtles are quick movers and strong swimmers; like most turtles, they will readily bite people who pick them up. The only species of turtle in North America that resides in brackish water—the diamondback terrapin (Malaclemys terrapin)— inhabits the coastline. The loggerhead (Caretta caretta) is the only sea turtle known to nest commonly on Alabama beaches, although four other species of marine turtles may frequent coastal Alabama. Unique to central Alabama, the flattened musk turtle (Sternotherus depressus) is restricted to the Black Warrior River System. In addition to three species of sea turtles, the Alabama red-bellied turtle (Pseudemys alabamensis) is listed as endangered by the federal government. This freshwater turtle inhabits shallow, vegetated backwaters along rivers and streams in parts of Mobile and Baldwin counties, especially in the Mobile-Tensaw Delta. Because it was believed to be endemic to Alabama, the Alabama red-bellied turtle was designated as the official state reptile in 1990. However, another apparent Alabama red-bellied turtle population has been discovered recently in the Pascagoula River, in southeastern Mississippi; if so, it is the only population known to occur outside of Alabama.
American Alligator (Order Crocodylia)
Alabama is home to only one species of crocodilian, the American alligator (Alligator mississippiensis), which occurs in freshwater habitats along the coastal plains. Closely related to dinosaurs and birds, predaceous alligators remain near fresh water, where they feed on fishes, turtles and other reptiles, birds, and small mammals. Naturally shy, alligators normally avoid contact with humans; they are not usually aggressive except in areas where they are fed and lose their fear of humans. Occasionally, however, an alligator will become a nuisance, especially in state parks (where people may mistakenly feed them), and require trapping and relocation. Like other crocodilians, alligators lay shelled eggs that they deposit in nests (in marshes) and cover with vegetation. As the vegetation decays around the eggs, it produces additional heat that helps to incubate the embryos. Crocodilians have conspicuous dermal bones (osteoderms) in their skin that make them appear rough and bumpy. They are also the only reptiles with a four-chambered heart, which is somewhat similar to that of endothermic ("warm-blooded") birds and mammals. All other reptiles have a three-chambered heart. Much like their avian relatives (and apparently some dinosaurs), the somewhat social alligators also vocalize and care for their young.
Lizards and Snakes (Order Squamata)
The order that includes lizards and snakes accounts for a majority (54) of the reptiles in Alabama; it constitutes the most recent group of reptiles to evolve. Species in this order are characterized by small scales, sometimes reduced or absent legs, and a three-chambered heart. Male lizards and snakes possess a paired copulatory organ known as a "hemipenis," whereas the male of other reptilian orders displays a single penis. Many lizards and snakes range throughout Alabama and neighboring states, although some of them are restricted to specific habitats such as sandhills, marshes, fields, rivers, rocky outcrops, or woodlands.
Alabama is home to 12 native species of lizards that also occur in other southeastern states; none are endangered or restricted to Alabama. Most unusual are the three species of limbless glass lizards (Ophisaurus spp.), which superficially resemble snakes. The majority of lizards, however, typically possess legs, conspicuous eyelids, and external ear openings. Among the more notable and widely distributed lizards are the terrestrial ground skink (Scincella lateralis), arboreal green anole (Anolis caroli nensis), and fence lizard (Sceloperus undulatus). All of these occur throughout the state. Also widely distributed, the six-lined racerunner (Cnemidophorus sexlineatus) is restricted to sandy upland habitats. All lizards in Alabama are insectivorous. The Mediterranean gecko (Hemidactylus turcicus) has become established in recent years in major coastal cities. This lizard is common on and in larger, older urban buildings with basements, where it can find shelter from the cold. Typically, it does not occur in natural habitats, and it is not known to be invasive. Because they are so mobile, more exotic species of lizards have been introduced than any other group of reptiles. Three other exotic species that may have become established in Alabama are the brown anole (Anolis sagrei), the Indo-Pacific gecko (Hemidactylus garnotii), and the Texas horned lizard (Phrynosoma cornutum). It is too soon to determine whether or not they may pose problems in the future.
Alabama has 42 species of snakes, six of which are venomous. Snakes lack legs, external ear openings, and eyelids. All snakes are carnivores, although many have very specific dietary requirements, including species that eat only worms, fishes, insects, mice, toads, or other snakes. Because snakes have jaws with ligaments that can stretch, they can eat food items that are wider than their own mouths and bodies. Although legless, snakes can burrow, climb, and swim very well. Most of them are shy and secretive, and they usually prefer to remain hidden under cover. Since they cannot hold their prey, most snakes subdue them by constriction, which consists of coiling around them and squeezing them until they suffocate. Most of the snakes in Alabama, including the venomous ones, occur in other southeastern states as well; none are unique to Alabama. There are many representative species of snakes that range throughout Alabama, including the midland water snake (Nerodia sipedon), black racer (Coluber constrictor), rat snake (Elaphe obsoleta), and Eastern garter snake (Thamnophis sirtalis). There are also several species of small, secretive snakes that are unfamiliar to most people, but are probably more abundant than those that are larger and more conspicuous.
Alabama has six species of venomous snakes: cottonmouth (Agkistrodon piscivorus), copperhead (Agkistrodon contortrix), Eastern diamondback rattlesnake (Crotalus adamanteus), timber (canebrake) rattlesnake (Crotalus horridus), pigmy rattlesnake (Sistrurus miliarius), and Eastern coral snake (Micrurus fulvius). Poison glands, which are modified salivary glands, are used by venomous species to subdue their prey. The first five species are pit vipers that possess infrared heat receptors called pit organs between the eyes and nostrils that can be used to detect the body heat of their mammalian prey. The pit organs can be used to identify these venomous pit vipers, which also have vertical (rather than rounded) pupils and a chucky body. The sixth species, the coral snake, is a burrowing species (related to cobras) that preys primarily on lizards and others snakes. Although it looks very similar to a number of nonvenomous species, it is rarely seen.
Many snakes, including rat snakes, corn snakes, king snakes, and rattlesnakes, play a very significant role in the environment
by controlling rodent pests and maintaining nature's delicate ecological balance. Regrettably, many people have irrational,
unfounded fears of snakes that prevent them from appreciating the complex, ecological contributions of these creatures. Like
other naturally occurring organisms, snakes contribute to a healthy food web and should not be routinely killed. Snakes are
generally nonaggressive and do not pursue people. However, when picked up or stepped upon, snakes will bite in self defense;
thus, they are best left alone.
All organisms—plants and animals, including humans—are interdependent within the environment and with each other. The nature and extent of actual ecological relationships among many organisms are not fully known. Reptiles play important roles in the complex food webs of many natural ecosystems. Lizards consume many insects, including some that are harmful; many snakes help control rodents and other mammals. Most turtle eggs are consumed by mammalian and avian predators that depend upon them for food. It is thus critical to preserve and protect natural environments and the organisms that live within them. The survival and stability of the biological world in which we live depend upon the maintenance of healthy, natural, biological diversity. Direct and indirect causes of urban expansion have resulted in the decline of wildlife of all kinds, including many reptiles. Like other groups of animals, the numbers of reptiles have been declining because of habitat destruction and fragmentation, pollution, fire suppression, inadvertent capture in traps, road traffic, the pet and food trade, and the introduction of invasive exotic plants and animals. Field biologists who spend much time in nature have observed that numerous snakes (such as rattlesnakes, pine snakes, king snakes, hognose snakes, and corn snakes) and other reptiles have been declining for many years. For example, the largest snake in North America, the endangered eastern indigo snake (Drymarchon corais couperi), is native to Alabama and other southeastern states, but it has not been seen in the wild in Alabama for more than 30 years.
Conant, Roger, and Joseph Collins. A Field Guide to Reptiles and Amphibians, Eastern and Central North America. New York: Houghton Mifflin, 1998.
Mirarchi, R. E., M. A. Bailey, T. M. Haggerty, and T. L. Best. Alabama Wildlife. Volume 3: Imperiled Amphibians, Reptiles, Birds, and Mammals. Tuscaloosa: University of Alabama Press, 2004.
Mount, Robert H. Reptiles and Amphibians of Alabama. Tuscaloosa: University of Alabama Press, 1975.
Pough, F. H., R. M. Andrews, J. E. Cadle, M. L. Crump, A. H. Savitzky, and K. D. Wells. Herpetology. Upper Saddle River, N.J.: Pearson/ Prentice Hall, 2004.
David H. Nelson
University of South Alabama
Published December 6, 2007
Last updated August 12, 2013