Covered in scales, reptiles are ectotherms (cold-blooded vertebrates) that are found on every continent except Antarctica and in every ocean except the Artic and Southern oceans. Right now, approximately 6,500 reptile species are known to exist.
Reptiles come in a large range of body sizes, shapes and colors. There are four main groups of reptiles recognized today: Crocodilians (alligators and crocodiles), Sphenodontia (tuataras), Squamata (lizards and snakes), and Testudines (terrapins, tortoises, and turtles).
Though some reptiles are live bearers, most reptiles lay eggs that are protected with a leathery shell to keep them from drying out. This distinguishes them from the amphibians, which must return to water to lay their eggs. In some reptiles, such as crocodilians and turtles, the gender of their babies is determined by the temperature of the nest. The eggs are buried in a nest of rotting vegetation which keeps the eggs warm.
Most snakes do not build nests for their eggs, but female pythons incubate their eggs by wrapping their bodies around them. The snake will occasionally “shiver” to help keep the eggs warm.
Very few reptiles show parental care towards the eggs or the young after they are born. Eggs become easy and tasty meals for a variety of predators. Young reptiles can be preyed upon by other large animals, including members of their own species.