Reptiles

Reptiles (Class Reptilia) are cold-blooded vertebrates that diverged from ancestral amphibians about 340 million years ago. There are two characteristics that distinguished early reptiles from amphibians and enabled them to colonize terrestrial habitats more extensively than their ancestors: scales and the ability to lay hard-shelled amniotic eggs. Scales protect reptiles from abrasion and loss of body moisture. Hard-shelled eggs provide a protective environment in which the embryo can develop.

There are nearly 11,690 species of reptiles, found on every continent except for Antarctica. The fact they are cold-blooded (also known as ectothermic) means they are incapable of maintaining a consistent body temperature on their own. They rely on the things around them to warm up or cool down. Their ability to move warm blood into the body core allows them to conserve energy. Today, scientists classify reptiles into four major groups known as "orders."

These four reptile orders are as follows:

• Crocodilia - crocodiles, gharials, caimans and alligators: 23 species;
• Sphenodontia - tuataras from New Zealand: 2 species;
• Squamata - lizards, snakes and amphisbaenids ("worm-lizards"): about 7,900 species; and
• Testudines - turtles and tortoises: approximately 300 species.

Clyde Catchment Reptiles

Within the Clyde catchment area, there are three native species of reptiles.