Feces are excrements that contain digested waste material, bacteria, cells that exfoliated from the linings of the intestines, and secretions (mainly from the liver). In humans and many other animals, the feces are excreted as a solid or semi-solid waste via the anus or cloaca. The process of evacuating feces from the bowels is called defecation.
Feces contain food that is not digested from the small intestine. As they pass along the large intestine, they are broken down by the bacteria in the colon. The distinctive odor of the feces is due to the action of bacteria. Thus, feces may contain compounds such as indole, skatole, thiols, and hydrogen sulfide. Water is removed from feces via re-absorption before they are excreted.
Feces are synonymous with terms such as manure (which is more commonly used in agriculture and husbandry) and stool (which is used to refer specifically to human feces). Feces of non-human animals are called differently, depending on the animal that excreted them. For instance, feces of cattle are referred to as cow dung but individual droppings may be called cow pats. The feces of deer are called fewmets. Feces of birds are referred to as guano or droppings. Scat is the term used to refer to the feces of wild carnivores. Spraints is the term for otter's feces. Frass is the feces excreted by caterpillars and other herbivorous insects.