Congratulations on your new snake! It’s a boy! Wait, no… It’s a girl! Actually… who even knows?!
Sexing a snake is easier said than done!
You see, snakes aren’t like dogs, humans, or other mammals. Their hidden reproductive organs make it nearly impossible to tell males from females based on physical appearance.
Some species display small, key differences between the genders. Usually, identifying this takes a trained eye and studying many comparison photos. Now, there are some surefire ways to determine the sex of your snake based on its internal anatomy – but you may need to get an expert involved.
Depending on how certain you need to be, let’s discuss how you might be able to determine – or make an educated guess – your snake’s gender!
Table of Contents
How Old Does a Snake Have to Be to Tell Its Gender?
Some of the methods we will discuss can be used from day one of a snake’s life, and how the breeder or pet store determines the sex of the snake before selling it.
Other methods (mainly the ones based on external appearance) require that your snake reaches (or has nearly reached) sexual maturity.
Sexual maturity can vary a little bit between different species but typically falls into the two-to-four-year-old range.
How to Determine the Sex of Your Snake
From top to bottom, we’ll start from less reliable, beginner-friendly methods to surefire, expert-only ways of sexing a snake, or determining its gender.
Size and Appearance Differences, or Sexual Dimorphism
This method will depend heavily on the species of your snake.
Not all types of snake display sexual dimorphism or significant size differences between the genders. You will need to determine which particular differences apply to males and which ones apply to females for your species, even in those that do. Additionally, sexual dimorphism usually isn’t apparent until the snake reaches sexual maturity.
In ball pythons, females are slightly larger than males. In anacondas, females are roughly 4.7 times larger than males! Conversely, with rat snakes, males are typically around 14% larger than females.
Some vipers display a related trait called sexual dichromatism, or different colors for males and females. European adders are notorious for this trait, but there are other species, as well.
✅ Buyer’s Tip: Once you have decided on which species you are going to purchase, or if you already have your snake, do some more reading and photo evaluations to find out if the type of snake you own displays any sexual dimorphism.
This method of sexing a snake usually isn’t very reliable, but it’s useful if you are only looking for an educated guess.
In many python and boa species, you will see little “spurs” – bony remnants of the hind legs of their ancestors.
These look like rose thorns and are found on your snake’s belly, on the right and left side of your snake’s cloaca.
In most species, the spurs on a male are much larger and more well-defined than a female’s spurs. Males will use their spurs during combat with other males and help grab onto the female during mating.
Note that, since spurs are the remnants of rear limbs, some snakes do NOT have visible spurs.
Only snakes that haven’t changed or evolved very much still exhibit this piece of anatomy, like boas and pythons. Rat snakes and other colubrids typically do not have them.
As aforementioned, this isn’t an extremely reliable method…
A female may have huge spurs, or a male can have tiny spurs. Just like you and I, each snake’s body composition is individual and unique.
If you are only looking for a marker so you can stop calling your scaly pal “it” and start calling them “he” or “she,” this is a great tool.
If you have your heart set on purchasing a male or female for breeding purposes, do NOT rely on spurs alone.
Unless disappointment’s your thing…
To the trained eye, this method of sexing a snake can be VERY reliable.
However, it takes years of practice and dozens of snakes to compare to consistently and successfully identify a snake’s gender based on tail shape, alone. If you only own one snake, or you own two snakes of the same gender, and this is your first attempt, you probably will not be able to make any conclusions.
However, if you put a male and a female snake side-by-side, there is a definitive difference in the shape of their tails.
The reproductive organs of male reptiles are called hemipenes. Hemipenes are housed internally in the snake’s cloaca and are essentially two penises.
Other species of reptile, such as bearded dragons, also have hemipenes.
If you are looking at a male snake’s tail, you may notice these features:
- A longer length to accommodate the hemipenes.
- Thicker near the cloaca, then suddenly tapers after 8+ subcaudal scales or 2-3″, depending on the total length of the snake.
On the other hand, a female’s tail is typically:
- Shorter in comparison
- Evenly tapered from cloaca to tail tip.
Popping is usually more successful when performed on younger and smaller snakes.
Older, larger snakes generally have enough muscle tone to hold their organs inside.
Too much pressure while popping can injure a snake, so it’s ideal to have someone with experience show you how to perform this technique in person at first.
Popping a snake is achieved by applying firm but gentle pressure to your snake’s tail on the belly side, about three-quarters of the way from the cloaca to the tail tip. Without releasing any of the force, you slide your thumb up the snake’s tail towards its cloaca.
In males, this can push the hemipenes up and out of the vent. They will pop out, looking like two reddish tubes. Nothing will come out if it’s a female.
Again, I must reiterate that this method CAN be harmful if not done correctly.
You also run the risk of popping a “false female.” If the technique is performed incorrectly and there isn’t enough pressure, nothing will pop out, even if it is a male.
Probing is the preferred method for any intermediate to expert level snake keeper. If you’ve never attempted this technique, it can be beneficial to have an experienced keeper show you how it’s done.
There are also many youtube videos available that demonstrate the method.
You will need to purchase a kit of probes explicitly designed for performing this procedure. Some people use other tools, but that can be unsafe. Luckily, the probes are reusable indefinitely.
The probe is sanitized, lubricated, then inserted downwards into the cloaca or vent, towards the tail tip, on the right or left side.
Please do NOT attempt to go up towards the snake’s head, or straight towards the snake’s spine.
There will be a bit of resistance when you first insert the probe, but there should be no need to apply any noticeable pressure once you are inside.
If you are probing a female, you will have entered one of her scent glands, and you will only be able to insert the probe the equivalent depth of one to three subcaudal (bottom tail) scales. You will be in one of the pockets that house a hemipenis if you are probing a male. You will be able to insert the probe the equivalent depth of nine to fifteen subcaudal scales, on average.
The pressure used to insert the probe should be VERY mild, and once it is inserted, you should need to apply virtually no pressure to find the end of the hemipenis or scent gland pocket.
It can be easy to be squeamish about this technique and assume that it is a sensitive area for a snake.
Still, most experienced keepers have stated that their snakes don’t seem to react any more than they do to any other procedure that requires the animal to be restrained.
It is safer AND more reliable than popping and is overall the preferred method of determining a snake’s gender amongst snake caretakers.
An ultrasound is, without a doubt, the MOST foolproof way of identifying a snake’s gender, albeit slightly over the top and expensive for the everyday hobby snake owner or breeder.
This method is commonly used by large zoos and animal parks, especially with snakes and other reptiles utilized in a conservation breeding program. In addition to identifying the snake’s gender, ultrasound machines also enable veterinary staff and keepers to see if a female snake is developing egg follicles and how far along they are.
Some big-time snake breeders have caught on to these benefits and purchased a small ultrasound machine to use on their breeding animals and babies.
If you don’t want to invest in an ultrasound machine and want visual confirmation of a snake’s reproductive organs, you can also take your pet to your local exotic veterinarian, and they will be able to perform the ultrasound for you.
Wrapping Up How to Sex a Snake
Now that you’re equipped with the knowledge and know-how of sexing your serpent, the next step is to decide which method sounds the most ideal for you and proceed with the necessary steps.
Whether that means ordering your snake probe kit online or making an ultrasound appointment with your reptile veterinarian, congratulations on the upcoming gender reveal of your snake!