Why Do Reptiles Have Scales?: And Other Questions About Evolution and Classification

Why Do Reptiles Have Scales?: And Other Questions About Evolution and Classification — page 3
Classification of reptiles The main groups of reptiles are turtles crocodilians snakes lizards and tuataras Snakes and legless lizards look similar but they are different Lizards have eyelids and ear openings unlike snakes and a lizard’s tail makes up two thirds of its length while a snake’s makes up just a third Turtles Vipers Turtles tortoises and terrapins are among the oldest of today’s reptiles They have hardly changed since they first appeared more than 220 million years ago Vipers are venomous snakes that are found in the Americas Africa Europe and Asia They include rattlesnakes and adders They have long hinged fangs Most give birth to live young Crocodilians Crocodilians include alligators crocodiles gharials and caimans They first appeared about 84 million years ago and are the closest living relatives of the birds Colubrids About two-thirds of all snakes belong to the colubrid family Most are not venomous They live on every continent except Antarctica 6 Elapid snakes Elapids are a family of agile venomous snakes which live in warm parts of the world They include the king cobra and some tree-dwelling and burrowing snakes Sea snakes These elapid snakes have adapted to life in salt water They have evolved paddle like tails and have a gland that gets rid of excess salt Some have the strongest venom of all snakes