Sexing Mice

[Katt]

Adult mice are fairly easy to sex. Sexing young mice on the other hand takes practice and a good eye.

Females' vulva and anus will be much closer together than the males' anus and penis. Also, in females nipples will be visible. Sometimes they can be hard to find through the hair, but this can be helpful for sexing young mice. And of course in mature males, the testes will be visible - but watch out, when stressed male mice can retract their testes, so be sure that the mouse is comfortable with your handling before sexing.

Female:




Male:

[Katt]

*IMPORTANT NOTE!!!!* I am not holding the mice up by their tails in these photos. Allow the mouse to sit on your hand or a flat surface, and gently lift their tails out of the way. Their tails were not meant to support their body weight! Also, you can hold the mouse in a CAREFUL, gentle scruff to view the stomach. Be sure to support the bottom feet with your other hand so that the mouse's full body weight is not hanging from the scruff. Do not hold the mouse like this for extended periods of time as it can cause undue stress. I had an extra pair of hands to take photos so that I had both hands securely on the mouse for their comfort and safety! Be sure that you do the same.