Artiodactyl

Artiodactyl (Greek artios, “even”; dactylos, “finger” or “toe”), any member of the order of hoofed mammals, including cattle, pigs, goats, giraffes, camels, deer, antelopes, and hippopotamuses. All artiodactyls, with the exception of the collared and white-clipped peccaries, have an even number of toes on each foot. A majority of species in the order are native to Africa, but they are well represented in North and South America, Europe, and Asia. Australia has no native artiodactyls.

All members of the order support their weight on the tips of the third and fourth toes. Their remote ancestors had five toes. Through evolutionary modification, the first toe has disappeared completely, and the second and fifth toes are only vestigial (nonfunctional) remnants. These small appendages are located higher up on the foot than the terminal toes on which the animals stand. The vestigial toes, sometimes called dewclaws, serve no purpose except in pigs and caribou, preventing these animals from sinking into soft ground.

Each of the two large, supporting toes of artiodactyls terminates in a hoof. The deceptive appearance of these two hooves gave rise to the biblical term cloven hoof, which suggests erroneously that the two hooves derive from a single large hoof. The hippopotamus, unique among artiodactyls, has four toes of equal size and width.

Artiodactyls feed almost exclusively on vegetation, except for pigs, which also feed on eggs, small reptiles, worms, and carrion. Although artiodactyls lack upper incisors, and most species lack upper canine teeth, they have a pad in the upper jaw against which the lower teeth can operate. Artiodactyls rely mainly on speed and keen senses to protect themselves from predators even though most males have horns or antlers.

Artiodactyls were first classified in a separate order by the British comparative anatomist Richard Owen in 1847. The order is divided into three groups: those that do not chew cud, such as pigs; cud chewers, including camels and llamas; and true cud chewers with no upper front teeth. True cud chewers consist of the chevrotains (small, hornless, deerlike animals), antelope, cattle, deer, and giraffe.

Scientific classification: Artiodactyls make up the order Artiodactyla. Those that do not chew cud make up the suborder Suiformes, cud chewers make up the suborder Tylopoda, and true cud chewers make up the suborder Ruminantia.