How to Tell Male Turtles From Female Turtles. Most people who have pets are not animal experts. Being able to tell the male from female in some species, such as turtles, can be difficult for the average person, yet it is important to know. Shape, size and eye color are some of the ways in which you can learn the gender of turtles.
Determine the breed of your turtle, if possible, to facilitate the sexing process. ReptileChannel.com lists the different breeds and includes helpful pictures (see Resources below).
Be sure your turtle is a mature adult of at least 3 years old before you attempt to tell if it is male or female. Baby turtles do not yet have gender-distinguishing characteristics. Locate a reptilian vet with the Association of Reptilian and Amphibian Veterinarian's (ARAV) online directory if you need help determining the age of your turtle (see Resources below).
Look at your turtle's tail to help you tell if it is male or female. Male turtles usually have wide, long tails. Females tend to have smaller, shorter tails that are stubby in appearance.
Turn your turtle upside down and look at the vent, called the cloaca, on its body. The male turtle's cloaca is farther away from the shell than the female's. The female's cloaca is very close to the rim of the bottom shell.
Notice the shape of the bottom shell of your turtle, called the plastron. Males have slightly concave plastrons that curve up a little. This shape facilitates a successful breeding process. Due to the abundance of eggs in her body, the female's plastron is flatter or more convex, curving downward.
Take note of front claw size on your turtle. Females of most breeds have short claws on their front legs. Males of most breeds have very long, thin claws on their front feet.
Use eye color to help determine the sex of your turtle if you know its breed. Female box turtles tend to have brown eyes, while the males' eyes are red. This coloration is reversed in spotted turtles, with the females having red eyes and the males having brown.
Compare the overall body and shell size if you have two turtles of similar age. Female turtles of almost all breeds are larger than the males.