Sometimes snake owners want to know how to sex their snake (find out if their snake is a male or female), but telling the difference between the sexes is not as simple in snakes as it is in many other kinds of animals. Male and female snakes look similar externally, however, with a bit of experience, there are ways to differentiate the two.
The following methods of sexing snakes should only be done by experienced caretakers or veterinary staff. If you are a beginner in snakes and want to know the sex of your snake, please find an experienced reptile keeper or vet to demonstrate the following for you, as the methods carry a risk of injury to your snake if they are done incorrectly.
Sexing Snakes Using Tail Characteristics
Male snakes have a pair of hemipenes (sex organs) that normally sit inside their bodies and are shaped like tubes. They are located just below the cloacal (vent) opening and down along the tail on either side of the snake's midline. The hemipenes are basically two small penises that are kept safe inside the snake's tail. Female snakes do not have hemipenes.
Since these sex organs are housed inside the male snake, they may not be obvious to you, but there are visible clues that they are there. Because of the presence of the hemipenes, you can look at the shape and length of the tail to help you decipher whether or not your snake is a male. Males will have a tail (the tail is considered the portion of the snake starting after the cloacal opening) that is thicker and longer than their female counterparts and also tapers differently. It will be thick and then suddenly thin out to the tip. The female snakes have an overall thinner and shorter tail than a male has. It tapers evenly to the tip.
While the differences can be fairly notable when comparing snakes side by side, it is more difficult to sex a snake if you don't have a male and a female side by side to compare. This is why the following methods are more commonly used to identify a snake's sex more accurately than looking at tail characteristics.
Sexing Snakes Using a Probe
Probing a snake involves inserting a thin metal rod (called a snake probe) into the vent (cloacal opening) of the snake while they are awake. The special probe can be inserted further in males since they have a hemipenis on either side of the vent. The probe will drop down into one of these spaces that point towards the tip of the tail. When probing a female snake, the probe will not drop down into the vent very far because there is no space for it to go when you are directing the probe towards the tip of the tail (they only have small scent gland spaces).
Picture two long socks inside the tail of your male snake that open up at the vent of the snake and you are basically visualizing the hemipenes. The lubricated probe will slide into the vent in the direction of the tail and into one of the hemipenes located on either side of the snake's tail if it is a male. If it is a female, the probe will only drop in one to three scales (on average), but if it is a male, it will drop in nine to fifteen scales (on average). The difference between the sexes is dramatic with more of a pocket to drop the probe into in larger snakes. Probing a snake should only be done if you have someone to hold your snake still for you, have appropriately sized snake probes, and the confidence to do this carefully and correctly. You do not want to harm your snake so if you are unsure how to safely perform this procedure then you should not attempt it.
Sexing Snakes by Popping Hemipenes
If you don't know what it means to "pop" a hemipene, then the term may frighten you. "Popping" refers to popping the hemipenes out in snakes, or more technically, temporarily reverting them, so they are visible outside the tail (this is what happens when hemipenes prolapse). Pressure is applied with your finger firmly but gently on the snake below their vent where the hemipenis would come out. If it is done correctly, then a hemipenis will pop out. This can typically only be done on smaller snakes like ball pythons, and it can cause a lot of trauma if done incorrectly. This is not the preferred manner of determining the sex of a snake since it is difficult to do and you may not know if you were simply unable to pop the hemipenes or if the snake doesn't have hemipenes, to begin with.