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A slimy affair: How rattlesnakes ‘do it’


It was nothing new when a neighbor called and asked me to retrieve a rattlesnake from their premises. But to discover not just one, but two diamondbacks — and they were copulating on her back porch — that was new! In my decades of collecting/apprehending live rattlesnakes I had not seen this behavior before except (rarely) in zoos.

I grabbed my camera, then quickly focused and shot some pictures of this seldom witnessed event. Besides the clear and graphic image of the two snakes locked together, we can see the highly agitated female on top, ready to strike while the male is coiled quietly beneath her.

Among snakes, like other terrestrial vertebrates, reproduction begins via internal fertilization. So how do they do it? They have no arms or legs, which requires extraordinary modifications in both anatomy and behavior to get their genes into the next litter of baby snakes. First, instead of a single intromittent organ like other animals, the male possesses hemipenes. With this modification, a divided penis enables the male to mate regardless of whether the female is on the male’s right or left side. Moreover, both divided organs are studded with spines to maintain internal grip (and prevent premature withdrawal) once implanted inside the female’s cloaca. (Note: a cloaca is an internal reservoir characteristic of both sexes at the aft end of the body into which wastes are deposited prior to being expelled by the body. Baby snakes, in their protective transparent membrane likewise pass through the cloaca when born). Second, the female must be willing and compliant. If she is not, the male has no alternative except to continue with his courtship consisting of tongue-flicking along the female’s back and head. Once coupled, the pair will remain locked together from between one hour to two days.

During that time, they remain quietly in place unable to go their separate ways. In fact, for a “zoo man” trying to transfer two diamondbacks thus connected, into a carrying bag without injuring either of them was another first.

With the snake transfer completed, the bag with the two quiet snakes was placed carefully in my reptile room for the night to give them a chance to separate. Although I was greeted with two uncoupled rattlesnakes the next morning, they were highly agitated as I transferred then to their permanent individual quarters.

Here are some answers to frequently asked rattlesnake questions: From six to 65 babies (sometimes more) are born every one or two years (the average is approximately 20). Young are typically born in spring in May or in the late summer. Precocial, the young, are fully prepared to make their own living without any maternal support.

They can even deliver a toxic bite if their protective membrane is touched next to their tiny head by a curious finger prior to their emergence into the world. Babies are noiseless, although they have a button on their tail. After their first skin-shed shortly after they are born, they will add the first segment to their rattle and a faint bit of noise can be heard. Prior to hibernation, the babies will try to find their way to their mother’s den by following her scent trails or other rattlesnakes in the fall.

Can a male rattlesnake mate with two females simultaneously? Theoretically yes, but in the real world that would be terribly risky for the male if the females decided to go their separate ways.

And yes, like all babies they have big eyes and are cute. Well, kind of.

Ray Pawley, previously with Chicago’s Lincoln Park and Brookfield zoos and the Field Museum of Natural History, continues to consult for zoos and museums. He resides in Arabela, where his research on animal behavior and physiology is ongoing. Most recently he has directed the Hubbard Museum of the American West in Ruidoso Downs and lectures for national audiences. He can be reached at raypawley@pvtnetworks.net.