What are reptiles?

In everyday usage, reptiles include turtles, snakes, lizards and crocodilians, mostly vertebrates with scaly skin.

Body and reproduction

Scales help limit water loss and reptiles breathe with lungs. Body temperature is closely tied to environmental heat and behaviour, such as basking and moving into shade. Amniotic eggs provide a protective setting for embryos, but not all reptiles lay eggs in the same way: some give birth to live young. There are venomous and nonvenomous snakes; treating every reptile as dangerous is mistaken. In evolutionary trees, birds are closer to crocodilians than to other living reptile groups.

Ecological relationships

Reptiles may hunt insects, fish or small mammals, while some turtles eat plants. Land, freshwater and marine species have distinct habitat needs. Loss of basking, nesting and overwintering sites can affect populations. Behaviour should be understood in relation to climate, habitat and life stage.