How To Sex A Mouse/ Other Rodents.
Can you tell the difference?
Lets start this off by saying I quite frankly do not understand how people can mix up the genders especially in rodents. It is incredibly easy to tell and will take no more than a few seconds of your time for each mouse, hamster, gerbil, rat etc you have.
First of all the age of sexual maturity of mice. Mice become sexually mature between 4-6 weeks of age but should not ever be bred before three months, four is a better starting point. At 3-4 weeks you should be able to notice the small protruding testicles of the male mouse beginning to show when you lift them up. They will be resting just before the rodent's anus and a good gap between the penis and testicles.
Lift up your mouse in your hand or wait for it to climb the bars of the cage so you can get a good look. A male mouse will have a small tube which will usually be slightly moist at his lower abdomen and a fluffy gap before you see his testicles showing. These are visible from 3-4 weeks of age depending on the mouse some grow large some don't show much. Male mice do not have nipples which often show on both angora and standard mice (although they may be harder to see with long fur). Male mice are built slightly stockier often with larger cheeks which are rounded unlike the straighter softer face of the females. However males and females are the same size, some males are larger some females are larger it depends on the age and the type of mouse so you really can't see a mouse think its bigger and assume it's a boy it doesn't work that way.
Female mice nearly always have showing nipples, if you cannot see them well brush back the fur against the direction of growth and you should be able to see them underneath, males do not have nipples. The female will also have a small circular nub fairly close to her anus that when she stretches you will see a small opening in a slightly triangular shape which is her vagina. There will be a little stripe of fur before the anus which is very close to her. Her physical appearance will be softer even if she is a very large mouse she will have a very feminine appearance and not be a stocky build mouse like the males.
Remember that female mice are far more active than males this may give you and extra indicator.
When you purchase your mouse in the pet shop look out for designated tanks labelled male and female to show they have been pre sexed and are kept separate from each other. When you choose your mice you can ask the shop assistant to double check for you which they will be more than happy to do that way you can put your mind at rest knowing you have two females or a male and a female or two males you know what your getting and don't get a shock to find a dead mouse or a litter of babies.