Impalas are found in the grassland regions of central and east Africa. Like other ruminants, they can regurgitate food in small amounts once it has been partly digested, for chewing again, re-swallowing, and further digestion. This enables them to obtain a lot of food in small amounts once it has been partly digested, for chewing again, re-swallowing, and further digestion. This enables them to obtain a lot of food in a short time, then retreat to a safe, sheltered place to digest it. When grazing, an impala grasps vegetation between its spade-like incisors (1) and a hard upper pad (2) and pulls it up rather then biting it off. The molars (3) are ideal for chewing. The gap between incisors and molars (4) allows the tongue to mix food with saliva. The powerful masseter muscle (5) moves the jaw up and down, while other facial muscles move it side to side for grinding.
A ruminant is a cud-chewing, even-toed, hoofed mammal. Examples include cattle, sheep, goat, antelope, giraffe, deer, okapi, and chevrotain. All except the chevrotain have four-chambered stomachs.
Ruminants regurgitate and re-chew their food once having swallowed it. They feed by filling one compartment of a three- or four-chambered stomach with unmasticated food, and bringing it back up to the mouth again to be fully chewed and finally swallowed. This method of feeding is an adaptation in many herbivores to increase the time available for digestion of relatively indigestible vegetable matter.