Cloaca — A shared internal chamber connected to the terminal digestive, urinary and reproductive tracts. Distinguishing the chamber from the external opening, or vent, makes the anatomy clearer.
Understanding by example
Excretion and reproduction are discussed around the same region because several tracts connect there. The visible opening alone cannot reveal the internal structures or reproductive condition, and surrounding anatomy and sexing methods differ among species.
Common misconceptions
Calling the cloaca simply an anus omits its urinary and reproductive connections. If swelling, bleeding or protruding tissue appears, do not diagnose the cause from appearance or push tissue back in. Record photographs and timing and consult a reptile veterinarian.
Related reading and sources
For species-specific context, see Reptile Anatomy and Reproduction. Browse the full glossary.
Basic reference: Merck Veterinary Manual: Overview of Reptiles.