Cloaca

From Freepedia

For other meanings, see Cloaca (disambiguation)

In zoological anatomy, a cloaca is the posterior opening that serves as the only such opening for the intestinal, urinary, and genital tracts of certain animal species. All birds, reptiles, and amphibians possess this orifice, by which they simultaneously evacuate both urine and feces. Monotremes also seem to possess one. In contrast, each individual among most species of placental mammals and bony fishes has, in lieu of a cloaca, a specialized opening for at least one of these tracts.

Excretory systems with analogous purpose in certain invertebrates are also sometimes referred to as "cloaca".