1. Location and shape of the excretory hole: The excretory hole of the male northern tortoise is close to the tail, and the hole is elongated. The excretory hole of the female northern tortoise is close to the plastron, and the hole is circular in shape.

2 , the thickness and size of the tail: malenorthern tortoisethe tail is thicker, female Northern tortoisesthe tail is thinner and shorter.

3. Whether the plastron is concave: The male northern simulacrum has obvious depression, while the female northern simulacrum is flat.