Bipedalism

Bipedalism is the condition of having or using only two feet for locomotion. This form of movement is found in a few groups of animals on Earth. Throughout the course of evolutionary history, the use of bipedal movement came forward several times as an adaptation to the environment, including a a point in human evolutionary history.

The use of bipedal movement is thought to be a key element in human evolutionary history, as it is part of what separates humans and their ancestors from the other Great Apes.

Species Displaying Bipedal Movement

There are many species on Earth that use bipedal movement as their primary means of terrestrial locomotion, and also some that can use bipedal movement when pressed to escape danger.

Lizards

Several species of lizard walk or run on their hind legs when trying to escape predators. Lophognathus longirostris is an example that is closely related to the frill-necked lizards, and runs on its back legs to gain speed and agility over short distances. Physignathus lesueurii, another relative, is capable of running for short distances on the surface of water.

Anatomical Correlates in Humans and Bipedal Human Ancestors

Through looking at the osteology of humans and their close relatives in the fossil record, a few key anatomical traits for the particular bipedalism associated with humans have come forward. A combination of these traits makes it possible for humans to walk upright and allows scientists to diagnose whether a fossil likely used bipedal movement or not.