AFRMA

American Fancy Rat & Mouse Association

Sexing 101 (sexing rats and mice)

Baby Mice

Baby Mice
2-day-old baby mice. The female on the left, the male on the right.
Baby Mice
2-day-old baby mice with the female on the left, and the male on the right. Note the white patch in the middle–this is the stomach with milk in it.
6-day-old baby mice
6-day-old baby mice. The female on the left, the male on the right. You can see the teat marks starting to show up on the female.
6-day-old baby mice
6-day-old baby mice. The female on the left, the male on the right. You can see the teat marks starting to show up on the female.
16-day-old baby mice
16-day-old baby mice. The male on the left, the female on the right. You can see the teat marks on the female. Note the “line” from the anus to the urethra on the female. On males this area is furry.
16-day-old baby mice
16-day-old baby mice. The male on the left, the female on the right. The teat marks still show up on the female at this age.

Baby Rats

Baby Rats - 2 days
2-day-old baby rats. The female on the left, the male on the right.
Baby Rats - 2 days
2-day-old baby rats. The female on the left, the male on the right. You can see that they had just eaten and have full tummies (white patch). The black spots are their belly buttons.
 
Baby Rats - 7 days
7-day-old baby rats. The female on the left, the male on the right.
Baby Rats - 7 days
7-day-old baby rats. The female on the left, the male on the right.
 
Baby Rats - 13 days
13-day-old baby rats. The male on the left, the female on the right. You can see the teat marks on the female at this age. The belly button spots still show.
Baby Rats - 13 days
13-day-old baby rats. The male on the left, the female on the right. You can see the teats on the female at this age. The belly button spots still show.
Baby Rats - 19 days
19-day-old baby rats. The female on the left, the male on the right. The male has small testicles showing at this age.

Baby Rats - 19 days Baby Rats - 19 days
19-day-old baby rats. The female on the left, the male on the right. Note the “line” from the anus to the urethra on the female. On males this area is furry. The male has small testicles showing at this age.

Adult Mice


Side
The side view of an adult male mouse.

The bottom view of an adult male mouse.
Side
The side view of an adult female mouse.

The bottom view of an adult female mouse.
The teats are clearly visible.

Adult Rats



Back view of young Seal Point Siamese rats.
The female on the left, the male on the right.

Adult male rats “letting it all hang out.”

The side view of an adult male rat.

The bottom view of an adult male rat.

The side view of an adult female rat.

The bottom view of an adult female rat.
You can see the vaginal opening just below
the urethra.

Updated March 22, 2014