A snake is an elongate reptile of the suborder Serpentes. Like all reptiles, snakes are ectothermic and covered in scales. All snakes are carnivorous and can be distinguished from legless lizards by the lack of eyelids, hind limbs and external ears.The 2,700+ species of snakes spread across every continent except Antarctica range in size from the tiny, 10 cm long thread snake to pythons and anacondas at 9 m (30 ft) long.ll snakes are carnivorous and can be distinguished from legless lizards by the lack of eyelids, hind limbs and external ears. The 2,700+ species of snakes spread across every continent except Antarctica range in size from the tiny, 10 cm long thread snake to pythons and anacondas at 9 m (30 ft) long.