baby mice question

[crazyd82]

How old do baby mice have to be before you can tell the sex of them? Is the difference easy to see?

 

[insomniac101]

It's harder to tell when they're little. By the time you can see the obvious difference, males are able to impregnate females. I found this site while surfing for information on a gravid female I bought. Click HERE

Kathy

 

[snowpig]

I sex mice all the time for work. It's fairly easy to tell when they are about 8 days old, mostly by looking for the (as that website posted says) nipples.

A former coworker also told me that when they are a day or two old, the males will have a black dot near their anus (I'm guessing the undeveloped testes?). I've seen this before but I never tested it out to see if it was true.

 

[Rigby & Marcy]

I can tell from a couple of days old if I have both sexes to compare to each other. Very simply put, the anus and genitals are two "dots", and on males the dots are further apart from each other than on females.

 

[crazyd82]

Thanks guys. Our babies in the fuzzy stage but I was still able to tell them apart. Once they are weaned then into separate tubs.

 

[insomniac101]

Thanks guys. Our babies in the fuzzy stage but I was still able to tell them apart. Once they are weaned then into separate tubs.

Yeah, I checked mine every day, and by the time they were about 3 weeks old, I got them separated by gender. I didn't realize how quickly they mature!

Kathy

 

[crazyd82]

Looks like I have 4 females and 3 males. How can I tell when they weaned and ready to be separated?

 

[Rigby & Marcy]

I watch the litter and see when the babies are out and about, and eating and drinking on their own. I give them several days after that. As long as the males aren't squabbling yet then you haven't left it too late.

 

[cornsnakeforsale_com]

"most litters can be weaned at 18-21 days" - https://www.rarc.wisc.edu/animal_health/guidelines/laboratory_mouse_breeding_and_weaning.html