Page "Bipedalism" Paragraph 12

The great majority of living terrestrial vertebrates are quadrupeds.

Among mammals, bipedalism is a normal method of ground locomotion in various groups of primates ( e. g. lemurs, gibbons and Hominina ), in the macropods ( kangaroos, wallabies, etc.

), and in a few groups of rodents, including kangaroo rats, gerbils and spring hares.

All birds are bipeds when on the ground, a feature inherited from their dinosaur ancestors.

Bipedalism evolved more than once in archosaurs, the group that includes both dinosaurs and crocodilians.

Many species of lizards become bipedal during high-speed, sprint locomotion, including the world's fastest lizard, the spiny-tailed iguana ( genus Ctenosaura ).

There are no known living or fossil bipedal amphibians.