How to Tell the Sex of a Turtle

With some animals it is easy to distinguish males and females. It’s hard to miss the antlers of a stag deer or the mane of a male lion. Turtles, on the other hand, don’t have obvious gender differences. In fact it’s virtually impossible to tell the sex of a turtle until it is close to being an adult (about 3 to 5 years of age). Just to make things more complicated, the sex characteristics vary from one species of turtle to the next! There are some features that apply to turtles in general, though. This guide describes these characteristics, along with a few examples of species-specific indicators.

Difficulty: Moderate

Instructions

1. Determine which species the turtle belongs to. Use a guidebook or online database (see Resources below) to help you identify the species. It’s also important to see if the turtle is full-grown, since the only way to tell the sex of a juvenile is to do a blood test and/or other sophisticated scientific analysis.

2. Start with the turtle’s plastron (lower shell). The plastron of a female turtle will usually be straight and flat while a male will have a concave plastron.

3. Examine the turtle’s tail and cloaca. The tail of a female turtle is shorter and thinner than that of the male. The cloaca is the opening that a turtle uses to excrete urine and feces and a female uses to lay eggs. In the female the cloaca is located on the underside of the tail close to the body but further out on the tail in male turtles.

4. Check other general characteristics. In most turtle species the females are larger than males and have smaller claws. Male turtles are more aggressive, especially in their mating behavior.

5. Look for sex differences that are specific to the turtle’s species. For example, a male box turtle’s eyes are red and the female’s eyes are brown. Among spotted turtles it’s just the reverse; the female spotted turtle has red eyes while the male’s eyes are brown.

Resources

• Guide to Turtle Species