red eared slider turtle gender

How to Tell Red Eared Slider Turtle Gender? (Is it a Male or a Female)

If you are a red-eared slider turtle owner or someone that’s interested in learning more about these animals, then you probably wondered how you can tell a red-eared slider gender. How can you determine if the red-eared slider is a female or male? 

It turns out, when they are younger, red-eared slider turtles can be pretty similar. So, it’s very difficult to determine the sex in their juvenile period. But, what about when they get older. At what point, visible differences between male and female red-eared sliders start to appear. 

In this post, we’ll closely look at all those little differences that make one turtle whether it is a female or a male. 

How to tell red-eared slider gender? To accurately tell the gender of a red-eared slider turtle you need to take several things into consideration. These following factors are important in distinguishing whether one red-eared slider is a female or a male:

  • Age
  • Size
  • Coloring
  • Shape and Size of Shell
  • Behavior
  • Length of Claws
  • Length of Tails
  • Cloaca

By examining some of these factors, preferably all of them, you can easily determine the sex of an adult red-eared slider turtle. If you have trouble figuring out by yourself, consult with a veterinarian. Now, let’s explain every factor on its own. 

Is my Red-eared slider turtle male or female 

People like to find out what gender their turtle is for various reasons. Some are interested in breeding them, others are just curious and want to learn more about their pet. Thankfully, there are some differences between male and female red-eared sliders that can help us determine their gender. Let’s see the first one. 


It’s very difficult and almost impossible to determine the gender of a baby red-eared slider turtle. Unless, of course, you are the breeder and you control the temperature and the conditions in the nesting box. 

Why is temperature so important and what’s its correlation with red-eared slider gender differentiation?

Apparently, the temperature during the incubation period plays a big role in forming the turtle gender. Lower temperature levels in the egg incubation period result in producing males, and higher temperatures result in producing female red eared sliders. 

Trying to determine the red-eared slider gender in their juvenile period will probably be unsuccessful.


As I’ve mentioned earlier, it’s very difficult to determine the sex of a baby red-eared slider.

You have to wait until they reach a certain size for you to be able to examine them. As adults, female red-eared sliders are usually bigger than the males reaching sizes between 10 to 14 inches. On the contrary, males are often smaller in size, reaching between 8 to 10 inches in length. 

As you have seen the size of the turtle is one factor that can easily tell you their gender. However, in order for this method to be successful, both red eared sliders need to be a similar age. Otherwise, this method won’t be relevant.


Red-eared sliders have recognizable colors, green bodies with red stripes going through their ears. As they grow older, these types of turtles change their colors from vibrant green to more dark appearance. This change is more noticeable in males rather than females. 

If you see a red-eared slider that has more dark colors on its body, then there is a big chance it’s a male turtle. 

Size and Shape of Shell 

Looking at the size and shape of the shell is another method that is limited mainly because you need to wait until your red-eared slider turtle reaches a certain maturity. This method is not applicable to baby red-eared sliders. 

In general, male red-eared slider turtles reach sexual maturity at age between 2 to 5 years old. Their size at that age is approximately 4 inches. On the other hand, females need a longer time to reach sexual maturity, usually between 5 to 7 years. 

At the time red-eared slider turtles reach sexual maturity, differences between both genders start to appear. In particular, the size and shape of their shells. 

The shell consists of two parts, the bottom part known as plastron, and the upper part known as a carapace. Both parts together form the shell. 

Female red eared sliders have flat or slightly convex plastron. Males, on the other hand, have a concave bottom part of the shell. Male red eared sliders have a  convex plastron in order to easily climb on the females during mating. And females have a concave plastron in order to have more room inside them for carrying eggs. 

By carefully observing these parts on adult turtles you can easily distinguish a female from a male red-eared slider turtle. 


There is one way that will certainly tell you the gender of a red-eared slider with a 100 percent accuracy. However, it doesn’t happen often. 

Female red-eared sliders that have reached sexual maturity can lay eggs, even without males near them. Usually, you will notice this behavior if your tank has ideal conditions. 

Length of Claws 

The length of the claws is a great indicator to tell the difference between male and female red-eared sliders. And it’s probably the easiest way to determine their gender. 

As any other difference, this as well can only be seen in adult turtles. Males have way longer claws than females, and the reason won’t surprise you. The primary use of their long claws is to help them during mating, or when they are in a fight with another male. 

Red-eared sliders, in particular, more than other turtle species have that pronounced difference between males and females. 

Length of Tails 

Another obvious difference between male and female red-eared sliders is the length of the tail.

In this case, just like with the claws, males have longer tails. It’s a difference that’s easily noticeable in mature turtles. 


Cloaca is the posterior orifice on turtles that serves as an opening for the digestive, reproductive and urinary tract. It’s the place where the sex organs are located, as well. If the cloaca is closer to the body, then it’s a female red-eared slider. If it’s somewhere on a hallway of the tail, then the turtle is a male. 

Final Thoughts 

For most of us, who are not interested in breeding these animals, not knowing the gender of our red-eared slider turtle isn’t a big deal. We only care about our turtle health and how we can improve the conditions they live in. 

However, if you are one of those that are curious to learn if the red-eared slider is male or female, then these differences between males and females mentioned above can indeed be helpful. 

Even if you are determined to learn how to breed red eared sliders, these pointers will be everything you need to know about turtle sex differentiation. 

Now I’d like to hear from you. What’s the gender of your red-eared slider turtle? And what was the way that helped you figure out? 

Let me know in the comments section. 

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