Even-toed Ungulate

Even-toed Ungulate

The even-toed ungulates (Artiodactyla) are ungulates (hoofed animals) whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in odd-toed ungulates (perissodactyls), such as horses.

Artiodactyla comes from (Greek: ἄρτιος (ártios), "even", and δάκτυλος (dáktylos), "finger/toe"), so the name "even-toed" is a translation of the description. This group includes pigs, peccaries, hippopotamuses, camels, chevrotains (mouse deer), deer, giraffes, pronghorn, antelopes, sheep, goats, and cattle. The group excludes whales even though DNA sequence data indicate that they share a common ancestor, making the group paraphyletic. The phylogenetically accurate group is Cetartiodactyla.

There are about 220 artiodactyl species, including many that are of great nutritional, economic, and cultural importance to humans.

A further distinguishing feature of the group is the shape of the astragalus (talus), a bone in the ankle joint, which has a double-pulley structure. This gives the foot greater flexibility.