How to Tell If a Turtle Is Male or Female

Many people ask how you can tell whether a turtle is male or female. One thing that makes turtles extremely different from other living animals – they lack visible genitalia. As such, it’s more difficult to tell the turtle’s gender than other animals.

In fact, male and female turtles look very similar at a glance. For most species, it’s typically impossible to just see a turtle and know the gender right away unless you take a closer look at their physical characteristics.

However, most of these physical differences between male and female turtles require a closer look to identify certain characteristics that distinguish the two. Finding out the gender of a turtle is not the easiest task, but this comprehensive guide will show you how to go about it.

Note that there may be other ways you can use to check your turtle’s gender apart from the ones discussed in this guide. Still, we believe these are sufficient enough to help you distinguish male turtles from female turtles. Before outlining the characteristics that differentiate male and female, read why you need to know the sex of your turtle.

Why You Should Know The Sex Of Your Turtle

Why bother with the gender of your turtle? Here are the reasons why


One of the reasons why turtle owners are more curious about the gender of their pets is so that they can name them appropriately. Remember that turtles live for many years if proper care is taken. The red-eared slider lives for thirty to forty years. The last thing you want is calling your baby turtle a male name only to reach maturity, and you realize it’s female.


If you intend to breed your sliders, you need to know the sex to ensure you have the right male and female to fertilize the eggs.

Egg Laying

It’s important to know when the females may start laying eggs to prepare their habitat to present their laying behaviors. It’s common for females to eat less during the laying season and becomes more active by digging. This is not seen in males since, unlike their counterparts, they do not dig

Aggression And Space

Most turtle owners house multiple pets together regardless of gender. It’s essential to note that some, like the male red-eared sliders, can become territorial against other males. If you decide to pet more than one male, ensure you provide more space and resources with ample caves and basking spots.

How To Tell If A Turtle Is A Male Or Female

Breeders Know The Sex

The way breeders determine a turtle’s sex is strange. Whether a turtle becomes male or female depends on the temperature used when incubating the eggs. Turtles that become male hatch in cooler temperatures while female eggs are incubated in warmer temperatures.

As a result, breeders will know the gender of all turtles born under their care because they know the temperatures they incubated in. So, if you will be buying the turtles from a breeder, it’s important that you find out the gender from them without analyzing the signs yourself.

How To Tell A Turtle’s Gender

You can determine a turtle’s gender by looking at the shell size, colorings, markings, plastron, claw size, tail, position of the cloaca, tail size and shape, and size as mating habits. However, turtles go through many changes from hatchlings to adults, making it hard to determine their sex until they achieve sex maturity.

If you are not a turtle breeder yourself and are not sure how to determine their sex, a little detective work is needed. Here are some things to consider when determining the sex of your turtle:

Check the Shell Size

The difference in size between two turtles may not obviously determine the gender of turtles until they attain sexual maturity. For example, male red-eared sliders reach their sexual maturity at about five years old at 4 inches in length. On the other hand, female red-eared sliders achieve that at about 6 -7 inches, taking up to 7 years. Female sliders grow larger than males like many species. After all, they need to carry eggs and protect their babies.

But this is not always the case. For example, female sulcata tortoises in the wild can reach up to 100 pounds while the males can grow to over 200 pounds.

Some say that the shape of the carapace (upper shell) could indicate gender. However, the carapace can vary from species, so it’s not a reliable indicator. Besides, injuries such as attacks by predators and falls resulting from careless handling can interfere with the shape of the upper shell.

Use Different Patterns and Markings

Different turtle species have different patterns on their shells. However, the patterns are not always consistent with some turtles, which can make it hard to tell them apart. For example, male box turtles have brighter and more colorful shells and eyes compared to their female counterparts.

But this is hard to tell in red-eared sliders because they have green bodies with yellow streaking as babies and muddy brown or black as adults. The darker coloration is mainly exhibited in the male red-eared sliders. Additionally, the outer scutes around the edge of the shell are a bit flared out in males and flat in females.

The Ornate box turtle is another perfect example of a sexually dimorphic turtle. Adult male ornate box has red eyes while the female has brown or yellow eyes. The male also shows greening colored heads with orange leg scales while females have brown heads and yellow scales.

Check the Plastron

The plastron is the bottom or underside of the shell on the belly. In some species, the shape of the plastron can easily distinguish males from females just by looking at the shape. Male box turtles, for example, have a flatter shell than the female that appears more rounded. You can determine the sex in box turtles by touching the bottom of their shell. If the plastron is slightly curved, it’s likely to be a male since the concave shape facilitates balance during mating without rolling off. On the other hand, females have a flat bottomed shell to provide more space to grow their eggs.

Just ensure you don’t turn the turtle upside down when observing the plastron and instead lift up your turtle to see. Also, pick it from the back at the tail to avoid bites and possible accidental drops, which can injure the turtle.

Inspect the V On The Plastron

You can also look at the underside of the turtle just below the tail to know the gender. But this aspect only works if you have to compare to turtles of the opposite sex. The male turtle tends to have a V-shaped shell notch, while the female turtles have U-shaped notches. Since the male has a concave plastron that opens into a large V. The female on the hand is narrower and convex with a more defined U.

Check the Claws Size

Claws play an important role for turtles, such as fighting off predators and digging. But the males also use the claws to attract the females during the mating season. They will do this by hitting their front claws together, producing a sound that attracts females. It’s probably why male turtles have bigger and longer claws than their female counterparts, who have stubby and much shorter ones.

Males also use long claws to defend their territory and fight off predators. The males also use the large claws for support during mating. So, if you have two turtles of the same size but can’t tell the gender, you can look at the claws and tell the difference. The red-eared slider show this characteristic more than any other turtle species.

The male turtle’s claws grow fast once they attain sexual maturity, while females’ claws grow steadily throughout their lives. For example, red-eared sliders males may not have developed claws until about three when they develop quickly. The diet can affect how fast the claws develop, so ensuring the turtle gets adequate nutrition is vital.

The Tail Size and Shape

The tail is yet another way to determine a turtle’s gender. The male turtle has much longer and thicker tails than the female, which are typically thinner and shorter. Perhaps there’s a biological explanation for this—the males’ genitalia within the tail, which adds to its length and strength. In fact, it’s too large that it sticks a bit from its shell.

Females’ genital is located further up in their bodies, so they do not have a thick tail. Females are characterized by shorter and thinner nails that are less noticeable. While this is a great way to tell a turtle’s gender, it can be flawed because many shops keep turtles in crowded spaces where they do mistakenly nip each other’s tails. Besides, the size may overlap between males and females with age.

Observe the Cloaca

The cloaca is a vent found in both male and female turtles just beneath the tail. However, the shape and location of the cloaca are different depending on gender.

In females, the cloaca is much rounder and might appear like a star. Besides, it’s located much closer to the turtle’s body at the tail’s base. It’s too close to the body that it seems as though disappearing inside the shell – just at the edge of the shell.

In males, the cloaca is much longer and has a slit-like appearance. The vent is located near the tip of the tail and relatively away from the body. The cloaca in males is typically found halfway down the trail as it aids mating.

You can also ask a vet to perform an endoscopic examination of a turtle’s cloaca. They use a small camera on a flexible stalk to see a turtle’s gonads. These can positively identify whether the turtle is male or female, even at a younger age. However, this is rarely done. Most pet owners want to avoid this expensive and invasive procedure and wait for other cues to show.

Check the Fingernails and Toenails

For some species, such as painted turtles and red-eared sliders, you can determine the gender by observing the fingernails or toenails. The two species have female-choice mating systems where the male vies for attention from females. The males use the fingernails to stimulate a female’s cheek as a way to test receptivity.  Once the female agrees to his advances, the male uses the fingernails to cling to the female shell.

As a result, Females have relatively shorter fingernails while males boast longer nails to help facilitate the behavior. However, baby and female turtles may do the same at times, so the act is not foolproof to determine the gender.

Mating Habits

If you think two turtles have reached their sexual maturity, observing them during the mating season can help you distinguish between them. Generally, males attract females by placing their long claws on the female heads and necks. Some will dance and pulsate them.

Can the Eyes of a Turtle Tell Its Gender?

Some experts say that the eyes of a turtle can sometimes tell the gender of your turtle. Male turtles tend to have bright red eyes, while females have a brownish iris. However, this may not be true because some females have also been seen with the same eye color.

What Causes Turtle to Be Born Male or Female?

The turtle’s gender is determined after fertilization. This means that the temperature the eggs are exposed to will decide whether the offspring will be a boy or girl. This is referred to as temperature-dependent sex.

Unlike humans and most mammals, the sex in turtles isn’t determined by the chromosomes they have. Instead, it’s the ambient temperature that determines the gender.

Research shows that if the turtle eggs incubate below 81.860F, the hatchlings are more likely to be males. And if the eggs hatch above 87.80F, the hatchlings will likely be female. Temperatures that fluctuate in both ranges will produce mixed hatchlings.

How Turning Down the Heat Leads to Male Baby Turtles?

Your turtles might be starting to lay eggs, and you’re thinking of influencing the sex. Well, the forks wisdom offers a wide range of advice, but this one technique has been backed by scientific proof: The temperature determines whether the eggs hatch male or female or a mix of both.

In a study published in the journal Science, researchers show a proven biological thermometer that turns a developing turtle into a girl or boy. Like other reptiles such as lizards and alligators, temperature is a key factor in the sexual development of turtles.

Researchers demonstrate how cooler egg incubation temperatures activate a key gene known as Kdm6b in turtles’ gonads and immature organs, which stimulate testis development. Researchers used a group of turtle-laid eggs and incubated them in temperatures of either 320C or 260C, and observed the way the genes and gonads turned during the early stages of development.

They found out that several genes either turned up or down, nowhere between. The first gene to shift is kdm6b, which became more responsive during cooler temperatures, and the gene resulted in males. Further experiments suggest that the protein found in this gene interacts with Dmrt1, a region of the genome that determines testis development.

How to Find Out the Eastern Box Turtle Gender?

The eastern box turtle is different from many species considering their eye color, shell and head coloration, carapace, plastron’s shape, and rear claws. The eyes of the male eastern box are red, while the female has brown eyes. The head and shell of the males are brightly colored than their female counterparts. A very reliable characteristic to check is the carapace’s rear edge that usually flares outwards in makes, unlike in females. Also, if the turtle has a concave dip within their plastron, they are likely to be a male because females are flat on the underside of the shell. The claws could also reveal the gender. Female box turtles develop longer nails to dig the nest.

How to Find Out the Gender of Your Red-Eared Slider Turtle?

If you just adopted a slider and are not sure what to look for in identifying its gender, perhaps the right step is to check the shell’s difference in size and shape if you have several sliders. This species achieves maturity around the age of 2-5 years for makes while the female will achieve it in 5 to 7 years.

Male sliders reach maturity at around 5 to 9 inches, while their female counterparts grow up to 12 inches. Once they reach maturity, they have about 4 inches difference, with females being larger than the males.

The shell shape may also give you a hint of its gender by looking at the underside (plastron). Males have a concave plastron, while females are typically flat. There may be exceptions to this rule, so you can proceed to the claws where males have longer front claws than the females, which have short claws.

The tail is also another common determinant, with females having long skinny tails compared to men’s thick and taller tails. The vent (cloaca) location is also different, with males having it closer to the tail’s end. The cloaca in females is found closer to the body at the edge of the shell. Finally, the color of the shell and head can tell the gender. Although they both have green bodies with bright yellow streaks as hatchlings, the male turtles tend to become darker than females as they age.

How to Tell the Gender of Baby Sulcata Tortoise?

The Geochelone sulcata, famously known as African spurred tortoises, are mostly identical at a glance. It may take some time before they can display their physical traits based on their genders. A sulcata tortoise usually develops the characteristics when they reach about 12 – 14 inches long.

Like many other species, a boy sulcata usually has a wider and longer tail while the female’s tail is hardly visible. The bottom of the plastron is shaped differently – the male’s underside is concave while the female has a slightly convex or flat underside. While at the plastron, check the anal notches as they differ as well. The females have a more circular notch compared to male’s anal scutes that are broader and v-shaped. What makes the male sulcata different from other turtles is they achieve bigger sizes than females. The male weighs about 120 pounds, while the female weighs half that at 75 pounds.

How to Tell a Turtle Is Male or Female – Summary

Determining the gender of a turtle is complex and somewhat confusing because you need to look at a combination of features to conclude. As stated above, some methods may not be reliable, so you might need to combine all the features we’ve included in this guide to determine a turtle’s gender.

 Kindly be careful when handling a turtle to see the characteristics and possible gender. The tail and the plastron are the immediate things you want to see first. Hold up the turtle carefully without scaring it. Not only will dropping the turtle scare him to death but it could get injured on hard surfaces.

Touch or take a peek at the plastron or the belly side. Males are slightly concave, while females are flat or slightly convex. The tails are also different, with longer and broader male tails than shorter and thinner tails in females. In case you can’t figure out the gender of your pet, wait for them to get older and try again.

Ask Your Vet

If you have thoroughly examined the turtle and can’t figure out the gender, perhaps you can ask for help from an animal expert. Not even the most experienced vets can know the gender by merely looking. The vet can quickly check your pets’ gender by performing various tests and examinations.

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