Perhaps you wish to breed red-eared sliders. Maybe you want to create a safe environment for your reptile and you don’t want to have several aggressive males in the same space.
Maybe you’d like to name your turtle and want a gender-specific name. Regardless of your reason, you’re going to need to know how to sex a red-eared slider!
There are physical as well as behavioral characteristics you can identify if you wish to determine the gender of a red-eared slider. For example, as adults, females are generally larger, but some of these determinants are more reliable than others. Let’s go through them and you can see what we mean!
How To Sex A Red-Eared Slider
Shell Size
The size of the shell can be used to determine the sex of an adult red-eared slider. Once fully matured, females are much bigger. red-eared slider reaches maturity at ages 2 to 8 – Males between the ages of 2 to 5 and females between the ages of 5 to 8.
When fully matured, the average carapace length of an adult male is 7 inches (18 cm) and the average carapace length of an adult female is 10 inches (25 cm).
As you can see females have much bigger shells and when you hear the term ‘Carapace length’, this refers to the length of the upper shell.
Males reach maturity between the ages of 2 to 5. Upon reaching maturity, they measure 3.54 to 4.33 inches (9 to 11 cm). They will continue to increase in carapace length until they reach a length of about 7 inches (18 cm).
Females, on the other hand, reach maturity at ages 5 to 8. Upon maturity, they measure 5.90 to 7.87 inches (15 to 20 cm). They will continue to increase in carapace length until they reach a length of about 10 inches (25 cm).
As you can see, there is a huge size difference between adult males and adult females, and this can be easily used to determine the sex of the individual.
Plastron Shape Differences
The shape of the shell can also be used to help determine the sex of the turtle. Now, you know that the carapace is the upper portion of the shell, but the plastron is the lower part of the shell that’s underneath the turtle. This is important, as the shape of the plastron differs between the sexes.
The shape difference is most evident in individuals that are at least 4 inches in carapace length.
Females have flatter plastrons that bulge out and this shape helps the female to nest.
Males have concave plastrons – curved inwards. This concave shape allows the male to easily climb atop the female for mating.
So, in summary, Males have concave plastrons and females have flat or convex plastrons.
Claw Size Differences
The size of the claws can help you to determine the sex of the red-eared slider. Males will have long foreclaws; while females have short foreclaws. The claws of the front feet (also known as foreclaws) of the female are stubby and short.
The claws of the males are much longer (see picture on left or top if on mobile) and these claws are useful during mating, as the male red-eared slider uses his long claws to grab onto the female’s carapace!
Before mating, red-eared sliders engage in a mating display activity known as titillation. This ritualistic display involves the male using the foreclaws to make vibrations near the female’s eyes. The male may also touch the female’s face and if the ritual is successful, then the two will proceed to mate.
Tail Size Differences
There are differences between the tails of males and females. Females have thin and short tails while males have long and thick tails. Using this technique can be tricky, however, until you’ve inspected a lot of red-eared sliders for practice.
The Males have larger tails for a reason — they need to house their sex organs within the tail, but the tail size alone isn’t conclusive, as you’ll also need to inspect the cloaca location on the tail.
Cloaca Position
The cloaca is an orifice located near/on the tail of the turtle. This opening is used for urination and the excretion of waste, and it is also used for reproduction. The red-eared slider is even known to breathe through the cloaca, as it allows them to absorb oxygen from the water.
With females, the cloaca is located very close to the body, almost under the shell. With males, the cloaca will be positioned nearer the end of the tail. During mating, the male mounts the female, and the positioning of the cloaca closer to the end of his tail allows the male’s cloaca to reach the female’s.
Behavioral Differences
Males and females may behave differently. While red-eared sliders aren’t as aggressive as some turtles out there such as softshells, musk turtles, or mud turtles, they can still be quite aggressive, and they are the most aggressive during the mating season when the males have to compete with the other males.
If you have several red-eared sliders within one enclosure then you are more likely to witness the aggressive behavior of the males. If a red-eared slider is suddenly being aggressive towards other members within its enclosure, then it is most likely a male.
This may be one of the chief reasons why female turtles live longer than males, according to an article from phys.org on turtle aggressiveness as it relates to their expected lifespans.
Females behavior changes, too, when it is time to nest. They’ll spend time searching for a suitable nesting location and you’ll see them scratching the substrate and trying to dig to prepare a nest. For this reason, you’ll need to provide a suitable nesting habitat for the gravid (egg-carrying) female.
If you fail to provide a suitable nesting site, the female may lay a few eggs into the water, but it is likely that they will retain most of the eggs. This is called egg dystocia and it is a serious health concern that can sometimes be fatal! If the turtle takes too long to lay her, eggs it can actually result in her death.
Sex Determination Based on the Temperature of the Nest
The temperature of the nest determines the gender of the hatchlings, so if you keep track of the temperatures within the nest before the turtles hatch, you’ can easily determine the sex of the hatchling’ll know their genders in advance!
This is the best way to determine the sex of a newly hatched red-eared slider.
Nests with temperatures above 85.3 degrees Fahrenheit (29.6 degrees Celsius) result in all female hatchlings and nests with temperatures below 83.48 degrees Fahrenheit (28.6 degrees Celsius) result in all male hatchlings.
Nests with temperatures within the ranges mentioned 85.3 degrees Fahrenheit (29.6 degrees Celsius) to 83.48 degrees Fahrenheit (28.6 degrees Celsius) will develop a mix of female and male hatchlings.
To be certain, keep the nests’ temperatures at 89.6 degrees Fahrenheit if you want female hatchlings, and keep the nests’ temperatures at 78.8 degrees Fahrenheit if you want male hatchlings.
Frequently Asked Questions
How do you tell if my red-eared slider is male or female?
There are several physical characteristics you can look at to determine the sex of your red-eared slider.
First, females have larger shells and are larger overall.
When fully matured, the average carapace length of an adult male is 7 inches (18 cm) and the average carapace length of an adult female is 10 inches (25 cm).
Males reach maturity between the ages of 2 to 5 and upon reaching maturity, they measure 3.54 to 4.33 inches (9 to 11 cm). They will continue to increase in carapace length until they reach a length of about 7 inches (18 cm).
Females, on the other hand, reach maturity between the ages of 5 to 8. Upon reaching maturity, they will measure 5.90 to 7.87 inches (15 to 20 cm).
They will continue to increase in carapace length until they reach a length of about 10 inches (25 cm).
Secondly, males have concave plastrons and females have flat or convex plastrons.
Thirdly, males have long foreclaws while females have short foreclaws.
Fourthly, females have thin and short tails, while males have long and thick tails.
Finally, a female’s cloaca is located very close to the body almost under the shell, while a male’s cloaca is positioned nearer the end of the tail.
How can you tell a male turtle from a female turtle?
All turtle species are different. As such, the features to look out for when determining the sex of a turtle may differ from one species to another.
For freshwater turtles, generally, females are larger and have short skinny tails, short foreclaws, and flat plastrons while males are smaller and have long thick tails, long foreclaws, and concave plastrons.
Among freshwater turtles or terrapins, males are darker in color while females are lighter in color.
Does a female red-eared slider need a male to lay eggs?
No, they do not, females may lay eggs even if they have not mated with a male. The eggs produced are unfertilized and cannot hatch.
As such, if you have a female freshwater turtle you NEED to provide a suitable nesting environment to avoid egg retention, as this is potentially fatal.
At what age do red-eared sliders mate?
Males nest between the ages of 2 to 5 while females nest at ages 5 to 8. Age is not the only determinant, however — the size also counts.
Females nest at a carapace length of 5.90 to 7.87 inches (15 to 20 cm) while males nest at a carapace length of 3.54 to 4.33 inches (9 to 11 cm).
Can turtles get pregnant without a mate?
Female turtles can and WILL lay eggs without a mate. Without the male’s assistance, the eggs laid are unfertilized and will not hatch.
Conclusion
Determining the sex of a red-eared slider can be slightly confusing if you do not know what to look out for. However, since the red-eared slider exhibits sexual dimorphism, you can use physical attributes to determine the sex or gender of an individual turtle.
For starters, males are smaller than females. Females reach a carapace length of about 5.90 to 7.87 inches (15 to 20 cm) with a maximum size of about 10 inches (25 cm). Males reach a length of 3.54 to 4.33 inches (9 to 11 cm) and a maximum of about 7 inches (18 cm).
Males have concave plastrons, while females have flat or convex plastrons. Males will also have longer claws and tails.
Nest temperature is another factor in determining the gender of hatchlings.
Nests with temperatures above 85.3 degrees Fahrenheit (29.6 degrees Celsius) result in female hatchlings and nests with temperatures below 83.48 degrees Fahrenheit (28.6 degrees Celsius) result in male hatchlings.
If the nest temperature ranges between 85.3 degrees Fahrenheit (29.6 degrees Celsius) and 83.48 degrees Fahrenheit (28.6 degrees Celsius), then you’ll have a mix of male and female hatchlings.
This concludes our tutorial on sexing your red-eared sliders. If you have any questions or extra information, be sure to leave a comment and thanks so much for visiting!
Want to know more about red-eared sliders? Check out these links!
- How to set up a red eared slider turtle tank
- Red eared slider care guide
- How fast do red eared sliders grow
- Red eared slider turtle facts
- Yellow belly slider vs red eared slider
- Are red eared sliders invasive?