Animals in the order Artiodactyla, or even-toed ungulates, include deer, antelope, giraffes, camels, llamas, hippopotamuses, pigs, cattle, sheep and goats. These are mammals whose third and fourth toes carry their weight, rather than the third toe only, as with horses.
Ungulates are large mammals that use the tips of their toes, which are usually hoofed, to support their body weight. The order Artiodactyla has about 220 species. They are native to every continent except Antarctica and Australia, and they have been introduced domestically into Australia. Artiodactyls are of special significance to humans for food and other uses.
Artiodactyls are arranged into subgroups according to their stomach anatomy. Ruminants are those with four-chambered stomachs that regurgitate and re-chew their food to digest it properly. Among the ruminants are cattle, goats, sheep, deer, antelope, yaks and giraffes. Pseudo-ruminants have three-chambered stomachs and include camels, llamas, alpacas, guanacos and hippopotamuses. Most pseudo-ruminates, similar to ruminates, ferment their food in the fore-gut and chew cud. Non-ruminant, or mono-gastric artiodactyls are those with stomachs that have only one chamber. Examples of these are pigs and peccaries, which are omnivorous rather than strictly vegetarian as the other subgroups are. These have developed large stomachs and long intestines in order to digest their food properly.