Order: Perissodactyla

Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla (/pəˌrɪsoʊˈdæktɪlə/, from Ancient Greek περισσός, perissós 'odd', and δάκτυλος, dáktylos 'finger, toe'), are animals—ungulates—who have reduced the weight-bearing toes to three (rhinoceroses and tapirs, with tapirs still using 4 toes on the front legs) or even one (horses, third toe) of the five original toes. The non-weight-bearing toes are either present, absent, vestigial, or positioned posteriorly. By contrast, the even-toed ungulates bear most of their weight equally on two (an even number) of the five toes: their third and fourth toes. Another difference between the two is that odd-toed ungulates digest plant cellulose in their intestines rather than in one or more stomach chambers as the even-toed ungulates do.