Instructions
Wait for the turtle to reach adulthood. It is difficult to visually determine the sex of an immature turtle. It can take three to five years for a turtle to reach adulthood. It is difficult to know how hold a turtle is just by looking at it. Ask the dealer how old the animal was when you bought it, then add the amount of time you have owned it. Bear in mind that turtles in captivity grow at a much faster rate than in the wild due to the consistent food supply.
Note the position of the turtle's cloaca. The cloaca is a small opening along the underside of the tail. It is the only such opening and is used both for elimination and reproduction. Note how close the cloaca is to either the tip of the tail or to the body. If the cloaca is closer to the body, almost under the shell, your turtle is most likely female. If the cloaca is nearer the tail's tip then your turtle is probably a male. The size of the cloaca is the same for both sexes.
Examine the turtle's claws. Note if the front claws are long and curved. If they are, your turtle is probably male. If not, it is most likely female. In many species of turtles, males use their enlarged claws during mating. The rear claws of both sexes are about the same size. Remember, however, that not all species of turtles have this difference between sexes.
Check the thickness and length of the turtle's tail. Typically, male turtles have short, fat tails and females have long and slender tails. Other than tail width and length there is no typical size difference between males and females of most species of turtles.
How to Determine the Gender of Greenhouse Turtles
Keeping pet turtles in your greenhouse allows you to keep your turtles "outside" even in colder months. You might be interested to know the gender of your pet turtles. While knowing the sex of your turtles is not essential to the actual care of your turtle, there is a simple pleasure in knowing your animals better. Determining the sex of your turtle by visual means is not foolproof and only works with adult turtles. At best, you can make an educated guess using visual means.