Instructions
Examine the plastron, the bottom of the shell. A concave, slightly inward curve, of the shell means the tortoise is probably a male. The concave shape of the plastron fits on top of the female's top shell while mating. Meanwhile the female's plastron will be flat.
Look at the tail. Male tails are thicker and longer than that of females because they are used to hold onto the females during breeding. Also, males will often hold their tails slightly to the side.
Determine the size of the gular scutes under the chin of the tortoise. Scutes are the scales that cover the tortoise's shell and the gular scutes are attached to the plastron, under the head. Often these scutes are larger on males, however you will need to wait until your tortoise is about 14 inches across before scutes are large enough for comparison.
How to Tell a Female From a Male Tortoise
Sexing a tortoise can be frustrating; many are sexually dimorphic so sex differences are usually subtle. Even if you are not planning to breed your tortoises, sexing them is beneficial for deciding the living arrangements of your shelled companions. Habitat size and animal behavior are directly dependent on the number of tortoises you have in one enclosure. For instance, keeping animals together influences the amount of stress the animals undergo, which can affect territorial aggression or their overall health. Also, breeding pairs are less likely to be interested in mating if they are housed together. Remember to be gentle when you handle your tortoise.