Cloacal aperture can be defined as the posterior opening on the body surface of the cloaca in vertebrates such as in birds, reptiles, fish, and amphibians.

Through their cloacal opening.

The cloacal opening is the anus. Aquatic turtles hibernate in the water during the winter months. Their body functions slow and the anus widens to allow water to circulate into the opening. The opening is similar to the gills of a fish. As water circulates through the opening oxygen is absorbed by the many capilaries located in the cloacal opening.

Chickens have a rectal (cloacal) region, but it is not fully bifurcated as in mammals.

crocodile excrete its nitrogenous waste through its cloacal opening