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Reptiles are vertebrates of the taxonomic class Reptilia including animals such as snakes and lizards (order Squamata), turtles and tortoises (order Testudines), and crocodilians (order Crocodilia). Commonly called "cold-blooded," reptiles are ectotherms, meaning they are unable to regulate their own body temperature and are instead influenced by the temperature of their surroundings. Reptiles are characterized by skin with scales or horned plates and commonly reproduce by laying eggs, although some types of snakes bear live young. In Alabama, Kentucky, Mississippi, and Tennessee, reptiles are represented by the three taxonomic orders listed below:

	Crocodilians (order Crocodilia)
	Snakes and Lizards (order Squamata)
	Tortoises and Turtles (order Testudines)

Ecological Importance of Reptiles

Reptiles play an important role in ecosystems as both consumers and as prey items. For example, snakes and other reptiles consume many small mammals and invertebrates, helping to balance these populations in the ecosystem. Reptiles can regulate plant growth as well. Aquatic turtles play a crucial role in regulating growth of aquatic plants, contributing to healthier aquatic ecosystems (NOAA Southwest Fisheries Science Center, 2006). Reptiles such as snakes, lizards, and turtles are a food source for many larger predators. Reptiles such as alligators and snapping turtles will consume other reptiles, including their own species (Fuller & Somma, 2002).

Reptiles in Alabama, Kentucky, Mississippi, and Tennessee

The southern states harbor the greatest diversity of reptiles in the U.S. In the Southeast, turtle species diversity is higher than anywhere else in the nation, along with a type of lizard called skinks that prefer the Southeast's abundant moisture (Stein, Kutner, & Adams, 2000). Water snakes of the genus Nerodia are found only in the states east of Texas. While mammalian and amphibian species diversity increases in mountainous areas, reptile species diversity is highest in the Mississippi Valley, an area lacking widespread variations in elevation (Stein et al., 2000).

Within Alabama, Mississippi, Kentucky, and Tennessee, reptile species number as follows: in Alabama, there are 85 species with one endemic species; in Mississippi, there are 82 species with one endemic species; in Tennessee, there are 58 species but no endemic species; in Kentucky, there are 53 species but no endemic species (Stein et al., 2000).

For additional Web resources about reptiles in Alabama, Mississippi, Kentucky, and Tennessee, refer to the NBII catalog query for reptiles on our "Reptile Web Resources" page listed on the navigation menu at left.