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How to Tell the Sex (Gender) of a Turtle: A Comprehensive Vet-Reviewed Guide

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By Nicole Cosgrove

male and female Himalayan box turtles on top of each other

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Reviewed & Fact-Checked By

Dr. Lorna Whittemore

MRCVS (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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Turtles can make great pets and are fascinating animals in the wild. There are more than 300 different species of turtle, some of which are regularly kept as pets and others that actually need a permit to keep because they are so endangered and their wild population numbers need to be protected.

Whether you are out in the wild and want to determine the sex of a turtle you have seen, for curiosity, or you have bought or adopted a pet turtle and want to be sure of its sex, there are several methods you can use. Which is the most effective method will depend on the species of turtle and potentially even how many turtles you have.

Before You Check

Always handle your turtle carefully and don’t stress it out with too much vigorous flipping or turning. Also, remember that turtles can carry salmonella. It won’t harm the turtle, but it could make you very ill. As such, when you do handle your turtle, avoid touching your mouth or putting your hands too close to your face and always wash your hands after handling.

The 6 Ways to Tell the Gender of a Turtle

1. Check with the Breeder

The temperature at which eggs are incubated determines whether the egg will hatch male or female turtles. Cooler temperatures often yield male turtles while warmer temperatures often produce females. If you bought the turtle from a breeder, ask them for details regarding the incubation. There is some variation in environmental sex determination by species so check which temperatures affect sex, if any for your particular species.

Some breeders keep detailed records and are vigilant regarding the temperature at which eggs are incubated and this could give you a good indication of the sex of a turtle. However, some breeders may not have this information, or you may not be able to get in touch with the original breeder.

2. Check the Shell

You can check the size and shape of the shell, but this does mean that you need to know the species of turtle and this method is only effective when the turtle reaches sexual maturity. This might not be until a turtle reaches 10 years old. Generally, female turtles grow bigger than male turtles, but this isn’t true of all species. You will have to research the species and ascertain the adult size of the male and female to determine sex

You can also use the shape of the underside of the shell to determine the sex. The plastron is the area that covers the turtle’s belly and in males, the plastron is usually concave, which means that it curves inwards. Female plastrons are flat and straight. However, environmental factors can influence this, and poor diet can also lead to the malformation of the shell and plastron, so this isn’t always a reliable method.

woman holding turtle
Image credit: Ivan Smuk, Shutterstock

3. Claw Length

One such method is to use their claws. They use their claws during mating to grab the female’s shell. As such, males have longer claws than females, but this may mean that you will need two turtles so that you can compare the length of the claws to one another.

4. Compare Tails

Another method that requires having two turtles of the opposite sex is to compare tails. Male turtles have their sexual organs tucked inside their tails, which means that they tend to be longer and thicker than the tails of females. The age and stage of sexual maturity can also have an impact on the tail length and girth, so this method may prove more effective in adult turtles, and those closer to sexual maturity.

5. Check the Cloaca

A turtle’s cloaca or vent is positioned on its tail and the position can be used to determine sex. The male’s cloaca is closer to the end of the tail whereas the female’s cloaca is closer to the base of the tail.

vet holding a turtle
Image Credit: Goldfish Studio, Shutterstock

6. Look at the Markings

Sexual dimorphism exists in some turtle species. This means that the markings and colors of males and females are different. This can make it easy to determine the sex, as long as you know the exact species of turtle. However, not all turtles are dimorphic, and in species that are not, this method won’t work. Markings and color can also change as turtles mature, which means that it might be necessary to wait until your shelled pet ages a little.


Turtles are fascinating pets that come in many shapes and sizes. Knowing the sex of a turtle is important, but it can be difficult to tell, especially if you have never kept turtles before and if you do not have multiple turtles to compare. You may be able to find out the sex by speaking to the breeder. Alternatively, you can compare tail size, cloaca position, or claw length between multiple turtles. And in the case of dimorphic species, you can determine sex by looking at the patterns and markings of the turtle shell, although not all species are dimorphic.

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Featured Image Credit: Masterpoofdula, Shutterstock

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