The buttocks of male hamsters are generally large and red; Female hamster's buttocks are generally inverted triangle, and the anus is small and closed. Individuals can see circular objects.

Male mice have hair between two points because their genitals and anus are far away. Because the little mouse is close, there will be no hair between two o'clock. It needs to be carefully identified before it can be correctly identified.

The distinction between male and female rats is mainly judged by the distance between anus and genitals. The distance between female genitals and anus is relatively close, while that between male genitals and anus is relatively open. In addition, mature male mice will have prominent testicles, which is very obvious for golden mice, gerbils and macaroni mice, but not obvious for maple leaf mice.