A ruminant is a mammal that eats and digests plant-based food such as grass. Ruminating mammals include cattle, goats, sheep, giraffes, bison, yaks, water buffalo, deer, camels, alpacas, llamas, wildebeest, antelope, pronghorn, and nilgai. All of them are Artiodactyla, cloven-hoofed animals. The word "ruminant" comes from the Latin word "ruminare" which means "to chew over again".