Reptile & Amphibian Forums

How can I tell the sex of my snake?

Sexing snakes is definitely a skill that requires a lot of experience. As a general rule, male snakes have longer, thicker tails when compared to females of the same species. Often this can be done by visually examining the undersurface of the snake's tail. If you don't have a snake to compare it to, it can be tough.

Another method of sexing snakes is called "probing". This involves using a thin, specially designed metal rod. It is inserted in the snake's cloaca and pushed posteriorly into the base of the tail. The rod will slide much further inside a male snake due to the cavity provided for their inverted hemipenes. Females have much shorter probe depths. Probing is best left to the experienced as you can easily injure the snake if you don;t know what you're doing.

A third method involves "popping" snakes and can often only be accomplished with young snakes. Poppping is basically manual eversion of the hemipenes. This is also a tricky procedure that takes time to learn. Basically, you use pressure from your thumb to gently massage fluid into the hemipenes and cause them to evert from the cloaca. Females, obviously, will not pop.

Was this thorough enough for you? I sure hope so. If any of these methods doesn't work, try and take a clear, close-up photo of the underside of your snake's tail from the vent down. Post it here and we can probably give you a good idea of whether your snake is a Watersnake or Watersnakette.

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Pierson Hill

Herpetology and Herpetoculture

I'll add a couple things here to what Pierson said. I also would leave probing and/or popping to someone who is experienced in either process. There's simply too much risk of injuring the animal if one doesn't know exactly what they're doing.

The taper of the tail is fairly reliable in the case of adults, but for young snakes I believe the rule of thumb is less reliable. The more gradual taper in males, at the base of the tail, is due largely to the presence of hemipenes. The lack thereof in females results in a more pronounced taper. But since the hemipenes may not be developed in young males, the taper may be pronounced in either male or femele specimens. (Someone please correct me if I've got this wrong.)

Finally, there's the unique case of the Diamondback Water snake, N. r. rhombifer. Adult males have several raised protuberances, known as papillae, under their chin. Females lack these features.
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MichaelB