Cloaca

Posterior opening in zoology

A cloaca ( kloh-AY-kə), pl.: cloacae ( kloh-AY-see or kloh-AY-kee), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilaginous fish and a few mammals (monotremes, afrosoricids, and marsupial moles) have this orifice, from which they excrete both urine and feces; this is in contrast to most placental mammals, which have separate orifices for evacuation and reproduction. Excretory openings with analogous purpose in some invertebrates are also sometimes called cloacae.

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