The female radiated tortoise usually has a smaller opening angle at the tail end of the plastron, because the female tortoise has a smaller tail. The male radiated tortoise has a longer and larger tail, and when it is held flat, the male tortoise will sometimes roll its tail up from the bottom to the front, a bit like mating.

To distinguish from the plastron, it needs a certain size to be seen. The plastron of the male radiated tortoise is obviously concave, which is more difficult to judge. Adult male turtles will actively smell each other's cloaca to confirm each other's gender, but female turtles will not.