New York - Unlike other reptiles and mammals, alligators sport a permanently erect penis that hide inside their bodies, a new study has found.
According to the study, their erect penises made of tough, fibrous tissue that shoot out of their bodies and get pulled back in just as quickly, the Huffington Post reported.
âIt is really interesting and really bizarre, very different from anything weâve seen in vertebrates,â study author Diane Kelly, an anatomist at the University of Massachusetts said.
Very little was known about how alligators mate, Kelly told LiveScience.
In 1915, one scientist briefly described the alligator penis in a paper, but âat the end of it he actually says something to the effect of âI have no idea how this thing worksâ,â Kelly said.
To find out, Kelly procured a few dead American alligators from the Rockefeller Wildlife Refuge in Louisiana, one of which was more than 13 feet (4 meters) long. She dissected the alligator and was surprised at what she found.
Hidden inside the alligatorâs waste and reproductive orifice, known as a cloaca (which is Latin for âsewerâ), was a nearly 2.75-inch (7-centimeter)-long, pasty white phallus.
When she dissected the penile tissue, she found it was filled with a stiff, fibrous material called collagen.
Kelly then filled the penis with saline fluid. In mammals, turtles and birds, inflating the vascular region of a penis with saline enlarges it, allowing anatomists to see how the penis becomes erect.
âI tried it with the alligator and I got no length change, I got no diameter change. I got nothing. It became very clear to me right then and there that there was something very different,â she said.
Kelly surmised that the vascular space inside the alligator penis was so full of collagen that it was simply too stiff to inflate.
To see how it popped in and out of the alligatorâs body, she tugged on various tendons and muscles in the cloaca region and found one set of muscles that caused the penis to shoot out. Another set of tendons attaches to the base of the penis like rubber bands, she said.
âAs soon as those muscles relax, the penis gets whipped back into its original position,â she said.
Kelly isnât sure whether the penis comes out only during mating or also at other times, though she thinks itâs the former.
Since crocodiles and alligators are closely related, crocodile penises probably work the same way, she said, though she and other scientists have never studied the crocodile penis.
The study is published in the journal Anatomical Record.