Ruminantia (Scopoli, 1777)
The biological suborder Ruminantia includes many of the well-known large grazing or browsing mammals: among them cattle, goats, sheep, deer, and antelope. All members of the Ruminantia are ruminants: they digest food in two steps, chewing and swallowing in the normal way to begin with, and then regurgitating the semi-digested cud to re-chew it and thus extract the maximum possible food value.
Note that not all ruminants belong to the Ruminantia. Camels and llamas are among the exceptions, a suborder known as Tylopoda. Also, there are a number of other large grazing mammals that, while not strictly ruminants, have similar adaptations for surviving on large quantities of low-grade food. Kangaroos and horses are examples.
1., 2. ^ Whistler, D. P. and S. D. Webb. 2005. New goatlike camelid from the late Pliocene of Tecopa Lake Basin, California. Natural History Museum of Los Angeles County Contributions in Science 503:1-40.
Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License