Tetrapods


A group of animals with four limbs.  Having limbs eventually helped animals leave the water to live on land, escaping predators in the water.  All tetrapods are also vertebrates.

Humans, wolves, bats, snakes, whales, and dinosaurs are all examples of tetrapods.  Even though some of these animals do not have four limbs, they evolved from ancestors that did have four limbs.  Fish and insects are not tetrapods.


Three Limbs
Most tetrapods still have four limbs, although there are many differences between the limbs. Here are a human arm, a dog's front leg, and a seal flipper.