One of the features that squamates (snakes and lizards) have in common with each other that distinguish them from other reptiles are dual reproductive organs in males, called hemipenes (or hemipenis, if referring only to one side). When at rest, this organ resides in the male’s tail, just to the rear of the cloaca (vent) and is inside-out. It is everted (brought to bear outside the body) or retracted similarly to how you might turn a sock inside out. One can often discern hemipenile bulges in lizards, which appear as symmetrical “bumps” under the base of the tail. In some lizards and snakes, the male’s tail is slightly longer and thicker at the base to accommodate the hemipenes.
This lesson is part of Certified Herpetological Guide. Enrollment is self-paced, with no deadline to finish (about 50 hours).
