Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla (from the Ancient Greek περισσός perissós, "uneven"; and δάκτυλος dáktylos, "finger, toe"), are hoofed animals—ungulates—which bear most of their weight on one (an odd number) of the five toes: the third toe. 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.
Despite their very different appearances, they were recognized as related families in the 19th century by the zoologist Richard Owen, who also coined the order name.
Cladogram below is for existing Perissodactyla
|This page uses content that though originally imported from the Wikipedia article Odd-toed ungulate might have been very heavily modified, perhaps even to the point of disagreeing completely with the original wikipedia article.|
The list of authors can be seen in the page history. The text of Wikipedia is available under the Creative Commons Licence.