Instructions
Lift the turtle if possible to check the underside or plastron of its shell. The bottom of the male's shell is generally concave, whereas the female's is mostly flat or somewhat convex. These differences may assist with mounting and carrying eggs.
Measure the distance from the edge of the plastron to the cloacal opening in the tail. If the opening is approximately two-thirds of the way from the shell edge to the tip of the tail, it's likely the turtle is male. The female's cloacal opening is closer to the shell.
Look at the shape of its shell. In some species, the female's shell has more of an arch for a rounded appearance, whereas the male's is slightly flattened.
Compare its appearance to that of other turtles of the same species if possible, as this can help you note the differences in tail shape, claw length and overall size. Usually, the male's tail is longer and broader than the female's, which is short and slim. Males tend to have longer claws than their female counterparts. Female turtles are also generally larger than males.
How to Identify a Turtle's Gender
The identification of a turtle's gender differs from that of furry pets such as cats, dogs and hamsters. The differing characteristics develop more clearly as they mature, making it nearly impossible to sex a turtle until it has reached at least two years of age. At that time, subtle differences become more apparent, but you may still have difficulty telling them apart. Knowing the species can ease the process, as it helps you compare the distinct characteristics of the males and females.