How to Tell if a Mouse is Male or Female

Mice make for fun, fuzzy pets and it’s only natural you’d want to know if you are dealing with a male or female. How else could you name him or her properly? You can tell if a mouse is male or female with a few simple steps and some keen observational skills.

Things You'll Need

  • Mouse
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Instructions

    • 1

      Hold the mouse in the cup of your hand on its back.

    • 2

      Look closely near the base of the tail on the mouse’s underside.

    • 3

      See how close to the tail the genitals are. A female mouse will have her small opening right at the base of the tail while a male mouse will have his farther away from the base of the tail.

    • 4

      Also note if the mouse has a small swelling, indicating maleness, on his underside near the base of his tail. Not all small swellings will be obvious so don’t use that as the only determination.

    • 5

      Pay attention to other characteristics that mark a mouse as male. Male mice’s urine stinks to high heaven. Female mice are much more scent-friendly.