Sexing Snakes

The correct identification of the sex of your snakes will play a key role if you wish to breed them.  An experienced keeper will have more of an idea on what exactly to look for when determining the sex, however with the help of photographs I aim to give you a good idea on how to do this yourself.

Visual Identification

The first method is to visually see a difference in tail size and structure.  Males have two hemipenes which are stored next to each other at the base of the tail.  Each hemipene is tucked into its own 'pocket'.  The effect of this is quite simple, it makes the tail appear fatter for a longer distance, generally making the overall tail length longer also.  A female's tail narrows right from the base, making it almost 'carrot' shaped.  The exact shape and length varies from species to species, but generally, the male has a longer tail.

 
Corn Snake = Female tail above, male tail below.  Notice the male has a thicker and longer tail in comparison to the female.  Both snakes are the same size and age.

Bulgarian Sand Boa - Female tail above, male below.  In many boa constrictors, the females are larger and so their tails are thicker.  However, a male considerably shorter than the female may have a longer tail.

Some species of snake are even easier to identify the sex.   In some boas and pythons, males have prominent 'spurs' either side of their cloaca.  This however, is not a guaranteed method in many species, as females too have spurs.

Probing

The second method is by use of a probe.  A small, rounded metal rod can be inserted into the tail through the cloaca into the two 'pockets' either side of the base of the tail.  The probe will penetrate farther into the male, whereas the female will only probe just a few scale lengths.  This method should be carried out only by experienced keepers; it is a dangerous task if wrongly executed.  Minimal force is needed for the probe to penetrate, yet it is a known mistake for people to apply too much pressure, resulting in the rupture of a female's scent glands.  A lubricant must be used on the probe, Vaseline or KY Jelly are common substances to be used in this manner.

Here the probe is inserted into the scent glands of a female corn snake.

Image to show how far the probe was inserted in relation to the tail length of a female corn snake.

Here the probe is inserted into the hemipenal 'pocket' of a male corn snake.

Image to show how deep the probe penetrated the male's hemipenal 'pocket'.

Popping

The third method can be used on juvenile snakes.  It is referred to as 'popping', which involves manually manipulating the hemipenes out of the male snake, while a female will slightly evert her scent glands.  This method works better with younger snakes, directly after hatching is the time to obtain best results.  At this age, the snake has not developed much muscle tone, making it relatively easy to force the hemipenes from the pockets.

Right Picture:  Author 'popping' a male juvenile corn snake.  The hemipenes are clearly visible.

I will explain how to do this if you are right handed like me.  With your left hand, hold the body of the snake upside down in such a manner that the cloaca is held above the level of the rest of the body.  With your right hand, pull the tail downwards slightly, and have your thumb resting approximately 2cm away from the cloaca.  Gently roll and push your thumb down and across towards the cloaca, while at the same time bringing the tail upwards.  This whole process sounds very complicated on paper, but I assure you it's easy once you get the hang of it.  I highly recommend you to be taught this method by an experienced keeper before giving it a go yourself.

By Chris Jones
Director of PetClub UK Ltd.

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