Reptile & Amphibian Forums

Okay I bought 2 mice and bred them in the hopes that my water dragons would take a liking to them but they showed no interest so now I have 15 mice. LOL anyways they are 3 weeks old now, and i was wondering if there is a way to tell male from female this young so i can get them split up before they have more babies.

baby mice are weaned at about 4 or 5 weeks of age. Males should be separated by 5 weeks of age. The distance between the anus and urethra is greater in males than in females. By 5 weeks of age the testicles of males should be noticeable.

Another thing to keep in mind, is that male mice tent to fight alot more if kept together. Brothers will get along better if housed in a large enclosure with plenty of exercise wheels, hiding places and several food and water bottles so they won't fight over them.

If you really don't want to keep the mice, I suggest finding them good homes or humanely kill them and sell them to a snake owner in your area.

This is a fail safe way.
Lift the mouse up by the tail and look at the anus. Some males, even adults don't show very pronuounced testes. The best way to check is look at the perineal area between the urethra and the anus. If there is hair in between then it is male. If there is a hairless area between the urethra and the anus in the shape of a letter "I" then it is female.

LOL that "I" I just typed is about actual size. Look for a hairless area like that. It will be female.

Hope this helped.
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0.1 Rubber Boa
1.0 Eastern Hognose 2003 super red
0.2 Eastern Hognose Snakes
3.3 Western Hognose Snakes
1.0 Durango Mountain Kingsnake
1.1 Woma's (new!)
Spadefoot
Black Knobbed Sawback
Northern Diamondback
Florida Redbellied Slider
Western Painted
Southern Painted
1.0 African Hedgehog
1.0 Sulcata

1 Pleco
2 Silver Dollars
3 Bosemian Rainbows
1 Cory Cat
1 Upside Down Catfish
2.0 Fire Guramis

uhh... I think that is it.

Thanks a lot. I have one of those plastic cages with like the big room and then 4 little tower rooms and space stations! LOL only one wheel but it has a room in it tooo but I will get a wheel for one of the other rooms. They are all kind of cute and I am going to try to keep them all as I coulnd't bare for them to be fed to something now. I will have to try again sometime to feed them to my lizards.

Okay... my turn to chime in. I have found it difficult in the past to sex mice also. The distance thing didn't work well for me. Must be a personal issue because that is how virtually everyone tells you how to do it. I find it easier to look for , well, nipples. Just as the pinkies are turning into fuzzies, for about 2 or 3 days, females will have noticeable nipples. After that brief period of time though, it gets difficult again, until they are older, and by that time you should have separated them. So we have come up with a "technique" of sorts. After we have determined the sex of the pinky/fuzzy we take all of the males and clip off about 3/8 in. of theire tales. We have stiptic powder ready and dip the tail immediately to stop any bleeding. I know it sounds harsh, but the pinks really don't seem to notice much. Plus, it is then VERY easy to tell males from females at a glance. Even as adults, the ones without a poit at the end of their tails are obviously te males.