Thursday, December 19, 2013

A helpful guide to determining the sex of your Russian tortoise

When you bring home your new Russian tortoise, you may wonder if you have a boy or a girl. If you bought it at a pet store, there is a good chance the sales clerk told you some nonsense about the tortoise being a baby and whatever sex they happen to think it is based on who knows what. You most likely have a male - the pet trade prefers to sell males because they stay smaller, they are easier to hatch (since they require a lower incubation temperature), and they won't produce eggs. However, some females do show up at pet stores, and many show up second-hand on Craigslist or other online marketplaces. Determining the sex (male or female) of Russian tortoises is fairly straightforward, based on the shape of their tail.

Are you a 'Bo' or are you a 'Bonita'?!
Unlike other tortoise species, Russian tortoise males do not have a concave plastron. The body shape of males and females is roughly the same, with small non-gender-specific differences from one animal to the next that are due to the different subspecies and environmental factors. Both can have a little 'claw' at the end of their tail (all males do, not all females do, but some females do).

Size at maturity can be one clue: mature males are significantly smaller than mature females: males are usually about 5" and rarely grow larger than 6 inches (exceptions do occur), while females as large as 12 inches have been reported. Most mature females end up about 8-10 inches large.

The easiest way to tell if you have a male or a female is to look at your tortoise's tail. I have drawn you a diagram, and will show actual photographs below. You can click on the diagram to enlarge it.

A quick diagram of male and female tails in Russian tortoises
The very simplified description is that males have a long, skinny, pointy tail in which the cloaca (vent) is shaped like a slit, and is close to the tip of the tail. This makes sense, since the male needs to be able to bring his reproductive organs close to the female, and the length of the tail needs to be able to accomodate his penis. Males often carry their tail tucked to the side.
Females have a short, fat, wedge-shaped tail, in which the cloaca (vent) is shaped like an asterisk (*) or pucker, and is closer to the body. This is important for easier passing of eggs, which are surprisingly large!
A Russian tortoise egg - woah, that's big!
The vent gets stretched out during egg laying, so a mature female's tail will look different after she has laid eggs.

Please keep in mind that a small tortoise (4.5 inches or smaller) will usually look female. My male had a small stubby tail until he was almost 5" long (SCL) and then his tail suddenly sprouted and got more pointy. Here is a picture of a baby Marginated tortoise's tail, which are sexed the same way Russian tortoises are:

This little Marginated tortoise looks female,
but we won't know for sure until she is MUCH bigger.
Below is a picture of my male when he was still very young. His tail was not very long, but I was pretty sure he was a male, because his cloaca (vent) was slit-shaped, and the tip was pointy.

A young male Russian tortoise's tail
As mentioned before, a male Russian's plastron (flat belly shell) is NOT concave as it is in e.g. Greek tortoises.
His tail wasn't very long yet,
but he carried it tucked to the side,
and the point was much skinnier than it would be in a female.
This is his tail now. It still isn't super long, but it is definitely longer, he carries it to the side, and his cloaca is slit-shaped:
A young male's tail.

A young male's tail with the slit-shaped cloaca (vent)
Here is a picture of a mature Russian tortoise male:
Woah, now that is one heck of a male tortoise tail. Long and pointy.
Next up, some pictures of female Russian tortoise's tails. First, some young, immature females. Mila was about 5" when I took this pic, but since our male showed no interest in her, I assume she was not mature yet.
This is Mila, she was about 5" long when I took this pic
When I first got Jill, she was only 4.5" long, so although her tail looked female, I wasn't 100% sure she was indeed going to keep a small, stubby tail. Now at 5.5" long, her tail remains small and stubby, so I am certain that she is indeed a girl.
Jill was only 4.5" long when I took this pic.
Next, the fat and wedge-shaped tail of a mature female who had not yet laid eggs yet:
This is a 6.5" female's fat, stubby tail.
This one has some shell damage, so please disregard the shape of the pygal scute above the tail.
The next picture shows the asterisk (*) shaped vent of a female. Note how the vent is fairly close to the body, and even though the tortoise is close to 8" long, the tail is TINY. This female has never laid eggs.
A large, mature female's tail before she ever laid eggs. Note the * shaped vent.
And finally, here is a very wedge-shaped tale of a very large female:
Mature female tortoises actually have fat deposits in their tails.
This gives them their unique shape.
This female has laid eggs, so her vent is no longer a little asterisk-shape, but rather, a pucker. The skin of her cloaca had to stretch significantly to let the eggs out, and while the muscles contract later to close everything up again, the skin will never look the same as a 'virgin' tortoise's tail.
The cloaca of a tortoise female that has laid eggs.
The shape of the anal scutes of the plastron, right above the tail, can vary widely in young Russian tortoises, and is not a reliable method to sex a tortoise, unless it is fully grown.

I hope this helps you determine whether you have a male or a female Russian tortoise. If you just keep one, then in the grand scheme of things, it really doesn't matter... one of our female's name is 'Timmy' - named by my oldest son when we first got her.


  1. yes it can be difficult sometimes even to the training eye!

  2. Very interesting. We see a lot of Gopher tortoises down here and the occasional box turtle in spring. Ill have to look a little closer next time.

  3. Very good information.
    Thank you

  4. thank you for this inforamation, very helful. the rep at PETCO had no idea how to tell.. lol

  5. Clear precise information thank you

  6. Great information. Abe my male Russian tortoise thanks you.

  7. Thank you for such detailed information! :) This is so helpful!

  8. wonderful and very helpful. Its hard to find good info on tortoises. Thanks a lot!

  9. Your photos are brilliant! I'm pretty sure I have a female now, her tail is longer than I'd expect and she does curl it to the side. But it's also fairly fat and the deciding factor was the cloaca. I wanted to get another young horsfield, but didn't want to risk it if I had a male - I hear the males don't get along.

    1. If you would like to email me a pic of his/her tail, I can also help you determine if you have a female or male. You can send it to biochemnerd(at)

      Also, just as a heads-up, I wouldn't recommend housing 2 tortoises of either combination together. 2 females will still fight. 1 male and 1 female will result in a very bitten, over-mated female. 2 males could result in 1 dead... I wrote more about this in the following blog post: - I hope this helps! :)

  10. great accurate information on the Russian tortoise, thanks for sharing!


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