Artiodactyl
Artiodactyls are placental mammals belonging to the order Artiodactyla (/ˌɑːrtioʊˈdæktɪlə/ AR-tee-oh-DAK-tih-lə, from Ancient Greek ἄρτιος, ártios 'even', and δάκτυλος, dáktylos 'finger, toe'). Typically, they are ungulates which bear weight equally on two (an even number) of their five toes: the third and fourth, often in the form of a hoof. The other three toes are either present, absent, vestigial, or pointing posteriorly. By contrast, most perissodactyls bear weight on an odd number of the five toes. Another difference between the two is that many artiodactyls (except for Suina) digest plant cellulose in one or more stomach chambers rather than in their intestine as perissodactyls do. The advent of molecular biology, along with new fossil discoveries, found that cetaceans (whales, dolphins, and porpoises) fall within this taxonomic branch, being most closely related to hippopotamuses. Some modern taxonomists thus apply the name Cetartiodactyla /sɪˌtɑːrtioʊˈdæktɪlə/ to this group, while others opt to include cetaceans within the existing name of Artiodactyla. Some researchers use "even-toed ungulates" to exclude cetaceans and only include terrestrial artiodactyls, making the term paraphyletic in nature.
The roughly 270 land-based even-toed ungulate species include pigs, peccaries, hippopotamuses, antelopes, deer, giraffes, camels, llamas, alpacas, sheep, goats and cattle. Many are herbivores, but suids are omnivorous, whereas cetaceans are entirely carnivorous. Many of these are of great dietary, economic, and cultural importance to humans.
Hippopotamuses have all four toes pointing out.
For pigs and other biungulates the second and fifth toes are directed backwards.
When camels have only two toes present, the claws are transformed into nails.
Lifestyle[edit]
Distribution and habitat[edit]
Artiodactyls are native to almost all parts of the world, with the exception of Oceania and Antarctica. Humans have introduced different artiodactyls worldwide as hunting animals.[42] Artiodactyls inhabit almost every habitat, from tropical rainforests and steppes to deserts and high mountain regions. The greatest biodiversity prevails in open habitats such as grasslands and open forests.
