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Why Do Snakes Have Two Penises and Why Are Alligators Always Erect?

Reptile reproductive parts don’t lack for variety.

More than 10,000 reptile species in every shape and size live on Earth, from garter snakes to crocodiles, and their nether regions are just as varied as the species themselves. Snakes and lizards have two penises, not just one. They are called hemipenes. University of Sydney researcher Christopher Friesen says having two hemipenes may benefit males during mating, according to National Geographic. Snakes form “massive mating aggregations,” in which five to 100 males compete for a single female by searching for her within the group of reptiles. “It might be advantageous to be flexible about which side of the female a male finds himself because they use the hemipenis closest to the female to mate,” said Friesen. But it’s not just the boys, female lizards and snakes have two clitorises, or hemiclitores. Their functions are poorly known, but should be considered a defining characteristic of female lizards and snakes. Meanwhile, male American alligators are always erect. Most, if not all, other animal penises inflate from a flaccid state, but not the alligator. Plus, their penis shoots out from inside the animal’s body and then bounces back like a rubber band. Diane Kelly, a researcher and animal phallus expert from the University of Massachusetts, told National Geographic in 2013 that this “permanently erect bungee penis is really weird.”

Read the full story at National Geographic