Even-toed ungulate (Artiodactyla)
The even-toed ungulates (Artiodactyla, from Ancient Greek ἄρτιος, ártios 'even', and δάκτυλος, dáktylos 'finger, toe') are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing posteriorly. By contrast, odd-toed ungulates bear weight on an odd number of the five toes. Another difference between the two is that many other even-toed ungulates (with the exception of Suina) digest plant cellulose in one or more stomach chambers rather than in their intestine as the odd-toed ungulates do.
Cetaceans (whales, dolphins, and porpoises) evolved from even-toed ungulates, so some modern taxonomists combine the two under the name Cetartiodactyla. Others opt to include cetaceans in the already-existing Artiodactyla.
The roughly 270 land-based even-toed ungulate species include pigs, peccaries, hippopotamuses, antelopes, deer, giraffes, camels, llamas, alpacas, sheep, goats, and cattle. Many of these are of great dietary, economic, and cultural importance to humans.