Explanation:

Rumination is a specialized digestion process found in most hoofed mammals. All of these plant-eating animals lack the enzyme cellulase, which is capable of breaking down the tough cellulose in plant cell walls. The stomach of these grazing herbivores consists of four chambers—the rumen, the reticulum, the omasum, and the abomasum—each playing different roles in the digestion process. The ruminant animal swallows its food rapidly without chewing, and later regurgitates it (brings it back up into the mouth), then masticates it (chews), and finally re-swallows it.