Cows are ruminants, animals with a unique digestive system that allows them to live on otherwise unpalatable foods by repeatedly regurgitating and rechewing them as "cud." The cud is then swallowed again and further digested by specialized bacterial, protozoal, and fungal microbes that live in the rumen, one of the four compartments of a cow's stomach. Learn more about a cow's digestive system in this video segment from Nature.

This video is available in both English and Spanish audio, along with corresponding closed captions.