Many herbivores also are ruminants.
Ruminant animals can be recognized easily because they chew frequently even when they are not eating. This chewing activity called rumination , is part of the processes that allow a ruminant to obtain energy from plant cell walls also called fiber . The digestive system of a cow includes four stomachs. The rumen is similar to a lake with a river running through one corner. The majority of the amino acids available to the cow comes from the bacterial protein synthesized in the rumen.