How to Determine a Turtle's Gender

Female red-eared slider backside and tail

It can be challenging to identify the gender of a pet turtle, especially if you didn't get it from a breeder that hatched the turtles in a temperature-controlled setting. An embryo's gender is determined by the temperature during egg incubation; colder incubation temperatures result in males, whereas warmer incubation temperatures result in female development.

Thankfully, certain turtle species make it simpler than others to tell a male from a female without knowing the temperature at which they lay their eggs. For instance, red-eared sliders exhibit sexual dimorphism and clearly differ in size and appearance from males to females.

Using Shell Size and Shape to Determine Gender

Most male and female turtles may not have noticeable size variations until they reach sexual maturity (and the diet can also play a role in the size of a turtle). Male attain sexual maturity around the time they grow to a length of 4 inches (and at about two to five years old). When females grow to a length of 6 to 7 inches, they are sexually mature (which may take five to seven years). In and many other turtle species, females will grow bigger than males, but the size disparity between males and females varies by species. For instance, in sulcata tortoises, males can grow to 200 pounds or more while females can weigh up to 100 pounds. The size of the male and female sea turtles might be the same. A turtle must have grown to adult size before its shell can be used to accurately identify its gender.

The plastron, or bottom of the turtle's shell, is another tool for identifying the gender of turtles. Female turtles have a flat plastron, whereas male turtles have one that is concave (curved in). These forms provide female turtles greater internal space to store eggs and make it easier for male turtles to mount a female during mating.

Using Claw Length to Determine Gender

Claws on the front foot of female turtles are frequently small and stubby. Males have substantially longer claws on their front foot than females do, especially red-eared sliders and other aquatic turtles. This is due to the fact that males use their claws to entice ladies to procreate. The males' long claws are also used to grip the top shells of the females during mating.

Using Tails to Determine Gender

The length of a turtle's tail is the most popular technique to identify its gender. Male turtles have long, thick tails, while females have short, slender ones. When compared to females, male turtles' vents (called cloacas) are located closer to the end of their tails. Of fact, if you have many turtles of both sexes to compare, it is easier to identify a turtle's gender by examining its tail length.

Using Markings and Coloration to Determine Gender

All red-eared sliders have mostly green bodies that are streaked with yellow, making it difficult to tell males from females. However, other color indications could. The tail, legs, and head are green with strong yellow stripes, while the plastron is yellow with irregular, paired black patterns. The yellow markings on red-eared sliders may become partially or completely hidden as they age because many of them take on a dark, nearly black hue. Male red-eared sliders are more likely to have this deeper coloring.

Another sexually dimorphic species of turtle is the ornate box turtle. Female ornate box turtles have brown or yellow eyes, whereas mature males have red eyes. The females have brown heads with yellow leg scales, while the males likewise have greenish-colored heads with reddish or orange leg scales.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.


"What Causes A Sea Turtle To Be Born Male Or Female?National Oceanic and Atmospheric Administration National Ocean Service, 2020", "Elmer, Nicole. Red-Eared SlidersThe University of Texas at Austin Biodiversity Center, 2020", "How Do You Tell Whether A Turtle Is Male Or Female?Olive Ridley Project, 2020", "Ornate Box TurtleSaint Louis Zoo, 2020" ;