Ruminants are mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through bacterial actions. The process typically requires the fermented ingesta (known as cud) to be regurgitated and chewed again. The process of rechewing the cud to further break down plant matter and stimulate digestion is called rumination. The word "ruminant" comes from the Latin ruminare, which means "to chew over again".There are about 150 species of ruminants, which include both domestic and wild species. Ruminating mammals include cattle, goats, sheep, giraffes, yaks, deer, camels, llamas, antelope, and some macropods.Taxonomically, the suborder Ruminantia (also known as Ruminants) is a lineage of herbivorous artiodactylas that includes the most advanced and widespread of the world's ungulates. The term 'ruminant' is not synonymous with Ruminantia. Suborder Ruminantia includes many ruminant species, but does not include tylopods and marsupials, which are technically ruminants.