Reptiles

The name "reptile" is generally applied to any of a group of ectothermic (cold-blooded) vertebrates in the Class Reptilia. Ectotherimic means that they need an "outside" source of heat to generate adequate body heat. Reptiles must regulate their body temperature by behavior, either by basking in the sun to warm themselves or by hiding under cover to keep cool. Some reptiles (such as lizards) look superficially similar to some amphibians (such as salamanders). However, reptiles are dry-skinned, not slimy. They are covered in scales or a shell. If they have legs, they have claws on their toes. Reptiles can range far from water sources because their skins retain water better than amphibian skin does. Reptiles lay amniotic eggs that have a leathery shell preventing rapid water loss.

There are about 6,550 living species of reptiles worldwide. Currently, 301 species of reptiles are recognized in North America north of Mexico. Reptiles live in a wide range of habitats, including forests, swamps, grasslands, deserts, oceans, and mountains. The Class Reptilia is composed of four orders. Species from three of these orders occur in North America: Order crocodilia (crocodilians), Order testudines (turtles), and Order squamata (lizards and snakes). The Order Rhynchocephalia has only two living species - the tuataras, which are found only in New Zealand.

Crocodilia

The crocodilians are a very successful group, and their body form has not changed for 75 million years. They have a long snout, four well-developed legs, and a long, muscular tail used to propel them through the water. All crocodilians lay eggs in large mounded nests or in cavities dug in the soil. All members of this order are carnivorous. They eat fish, amphibians, reptiles, birds, and mammals. All species are protected by national and international treaties. Trade in hides or meat is regulated or prohibited. Only two members of this order, the American Alligator and the American Crocodile, are native to the United States. Only one of these, the American Alligator, occurs in Georgia. A third species, the Spectacled Caiman, has been introduced into a very local area in extreme southern Florida.

Testudines (Turtles)

Turtles have been in existence for over 200 million years. The characteristic shell or carapace formed from the fusion of vertebrae and ribs with dermal bones. The shell is covered with scutes that cover the bony shell. Turtles are long-lived animals. Some live from 20 to over 100 years, depending on species. Some species only eat animal matter while others eat both plants and animals. Turtles do not have teeth. Instead they have a sharp-edged beak, called a tomia, that is used to bite off chunks of food.

Squamata (Lizards and Snakes)

The Order squamata (scaled reptiles) is the largest order of reptiles with over 6,000 living species. It is mainly composed of the Lacertilia (lizards) and the Serpentes (snakes). Members of this huge order are found worldwide, except in Antarctica and on a few very remote islands. All have bodies covered in scales, and all periodically shed their skin. The squamata come in an amazing variety of sizes, shapes, and life styles. Scaled reptiles range in size from a 1.2 cm (0.5 in) long lizard to a 10 m (32.8 ft) long snake. Members of this order may be carnivorous or omnivorous. They live in a variety of habitats and may be aquatic, terrestrial, or arboreal. Some species lay eggs; others bear live young. Click here for more infomation on Georgia's snakes.

What are tuatara?

Tuatara means "spiny back" in Maori. Tuataras are reptiles but they are very different compared to lizards, snakes, and crocodiles. Tuatara have a primitive body structure that supports the theory that they are one of the oldest and most un-evolved species, having hardly changed in the past 220 million years. Tuatara have a scaly loose skin which is soft to the touch. They have a variable body temperature which enables them to survive in cold climates. They live in burrows and are nocturnal, hunting at night just outside their burrow entrance. They feed on worms, lizards, millipedes and small seabirds. Click here for more information about tuataras.

References

Georgia Wildlife Web
http://museum.nhm.uga.edu/gawildlife/reptiles/reptiles.html

Mount Bruce National Wildlife Center - Tuatara
http://www.mtbruce.doc.govt.nz/tuatara.htm