How To Tell The Sex Of A Box Turtle

Do you know how to tell the sex of your box turtle?

Have you wondered if your box turtle is a male or female? 

Besides your curiosity, it’s helpful knowledge to have, especially if you’re considering breeding your pets. 

Regardless, we’re here to help with this quick guide. 

How To Tell The Sex Of A Box Turtle

You determine the sex of a box turtle by looking at its overall features, including its eyes, claws, and tails. You should always use at least 3 or 4 characteristics to help determine the sex. The exact determining factors also depend on what type of box turtle you have. 

If you bought your turtle at a pet store, they may be able to tell you what the sex is, but it’s not for certain. 

To attempt to take the guesswork out of it for you, I’m going to go over all the characteristics to look at on your turtle to determine what sex they are. 

Why Learn The Sex Of Your Box Turtle?

While you may be curious about knowing the sex of your box turtle, it is helpful knowledge to have. 

If you decide to have more than one turtle, it’s essential to keep appropriate genders together. 

You shouldn’t house two males together. 

They are aggressive towards one another. 

When a male is ready to mate, they seem aggressive towards a female. 

If you want to breed them, it is fine to keep them together. 

Otherwise, you should separate the turtles. 

Typically there is not an issue with keeping multiple females together. 

It’s essential to ensure you have a proper enclosure if you plan on housing more than one turtle. 

Each turtle should have sufficient space. 

When Can You Determine the Sex of a Turtle?

If you have more than one turtle or more than one subspecies of turtle, you likely will begin noticing differences in their appearances as they grow. 

When a turtle is only a couple of centimeters long, it’s impossible to know the correct sex. 

It takes quite some time to be completely sure of the sex of a turtle. 

You will not be able to tell the sex of baby turtles or juveniles. 

You need to wait until they are adult size to ensure they have stopped growing. 

Until they reach maturity, the sex is still an unknown. 

Unfortunately, sexual maturity is not reached until the turtle is about 5 or 6 years old. 

Characteristics For Sexing Your Box Turtles

Mature males are usually bigger than female turtles but don’t base the sex on this alone. 

For example, female ornate box turtles can sometimes be larger than males.

Eastern box turtles (Terrapene Carolina Carolina), a subspecies of the common box turtle, are likely the most common type of turtle you will find as a pet in the United States. 

Other species found in the United States include the three-toed box turtle (Terrapene Carolina Triunguis), the Gulf Coast box turtle (Terrapene Carolina Major), and the ornate box turtle (Terrapene Ornata Ornata)

Each characteristic can vary dependent on what turtle species you have. 

Here’s a look at several physical characteristics to help with sex identification. 

Do Turtles Have Sex Organs?

While you might be embarrassed to ask the question, it seems like it would be an easy way to determine the sex of your turtle. 

Unfortunately, it’s not so simple. 

Males have a penis, similar to a mammal, but it is tucked away in their cloaca, so it is not visible from the outside. 

However, the one time you will be able to see it is when your turtle begins fanning. 

Fanning is when their genitals come out for display through the opening of their tail. 

There is no specific reason males fan, but it may be caused by stress or just a way to relax. 

In addition, female turtles do have a vagina, but like males, it is tucked away in their cloaca. 

Both males and females also use their cloaca to excrete waste. 

Take a Look at Their Eye Color

Box turtle eye color is a helpful characteristic when attempting to determine its sex. 

It is possible to determine the sex of your box turtle solely based on their eye color. 

Male eastern box turtles typically have orange, pink, or red eyes. 

A female eastern box turtle usually has brown eyes. 

If a female happens to have red eyes, they will be darker than those of a male box turtle.

As an exception, Florida box turtles do not have a difference in eye color.

Examining Their Claws

Looking at a turtle’s claws is a helpful characteristic in determining the sex of your turtle. 

If your box turtle has long claws, you likely have a girl. 

The long claws are handy when they are digging for a nest or when digging through mammal burrows. 

Boys tend to have shorter, thicker claws. 

If you have an ornate box turtle, you may notice the first toe of their hind leg turns inward. 

Head and Body Coloration

The color and markings tell a lot about your pet turtle. 

A female eastern box turtle, subspecies of the common box turtle, will have a lackluster brown head or yellow coloring, unlike male eastern box turtles, who typically have brightly colorful heads with yellow markings. 

Male western box turtles typically have shades of green, red, and orange. 

A male ornate box turtle typically has a green or yellow head, while females are deep brown. 

A male three-toed box turtle will occasionally have a red head. 

Shell Color and Size

While their shells’ color shouldn’t be the only indicator you base the sex on, it can lead you in the correct direction for determining the gender. 

A male box turtle has a much brighter colored shell than a female. 

A female shell tends to be longer, allowing more space to hold its eggs. 

If your turtle is not fully grown, its shell size should not be your only determining factor. 

The scales on your turtle’s shell are called scutes. 

As your turtle grows, the scutes will peel off, and a new layer will grow. 

It’s a similar process to how a snake sheds its skin. 

Taking a Look at the Cloaca

The cloaca is essentially your turtle’s rear end. 

The cloaca is the vent on the underside of its tail.

A male turtle will have a longer one and is slit-shaped. 

The female cloaca is round and star-shaped. 

Observe Their Tails

Female box turtles have shorter, thinner tails, while males have longer, thick ones. 

On Malayan box turtles, the female tends to have a stubby tail. 

A female’s tail typically stays downwards to cover its vent unless it is mating. 

It then will pull its tail up and to the side. 

Male box turtles have longer, thicker tails. 

The thick tail is used as a defense mechanism if another male turtle approaches a threat while attempting to mate. 

Examining the Plastron

If you gently flip your box turtle over, you will be able to observe their plastron, the underside of its shell. 

In male box turtles, their plastron has a slight concavity to it. 

The dip is helpful when it comes to mating. 

It allows the turtle to fit over a female’s shell. 

In contrast, female box turtles have a flat plastron, which allows them to grow more eggs. 

On occasion, a female box turtle may have a dip to its plastron, so unfortunately, it’s not a foolproof way to determine its sex. 

Shape of Carapace

The carapace on your turtle is the back, convex part of their shell. 

If you know where you are looking, this is a reliable factor in determining your box turtle’s sex. 

A male will typically have a flatter carapace, giving them a thinner appearance overall. 

The rear part flares outwards. 

In contrast, the carapace of a female turtle does not flare outward and is flat. 

Male box turtles also have a “V” shaped notch at the end of their carapace. 

This aids in mating.

Interesting Facts About Box Turtle Mating

If you are sure you have a male and female and are interested in mating, there are some interesting facts to know. 

Mating typically begins in the late spring, after turtles come out of hibernation. 

Once a male has found his mate, he hooks his claws into the female’s shell after mounting her. 

It’s not unheard of for the male to die after mating if they fall on their back and can’t flip over. 

Females can hold sperm in them for 4 years before laying fertile eggs. 

After the eggs are laid, they must be protected against predators, like birds, raccoons, and other wild animals. 

Final Thoughts

While there are several characteristics to look at in determining the sex of your box turtle, you may not know for sure until they are several years old. 

If you only have one pet turtle, you likely don’t need to know its sex, beyond just being curious. 

However, if you decide to house more than one turtle together, it is crucial to understand the sexes you are putting in one enclosure.