Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla (, ), 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.