telling male from female

[Krystal]

A co-worker of mine thought she had two males.....until one of the males had babies yesterday.....she believed what the pet store guy told her and knows nothing of rats herself.

I'm helping her the best I can...but males and females are supposed to be seperated at 4-5 weeks.  I can't tell them apart that young!!  I counted on my breeder to tell the truth when I got my babies......anyone have any info or know of a place online with advice?  I couldn't find anything when I searched.....

[Joe]

   By about week 4, you'll be able to tell the difference, since at that point while they're not nervous about something the boys will obviously be boys. My three were just weaned (maybe not quite, actually, but no mom in the tank anymore) when I got them, and I had no trouble telling that they were boys. As far as telling that young, I'm sure someone else can give you a link to see the difference.

[kmw]

You WILL be able to tell rats apart at 4 weeks  All you (or your friend) has to do is take two rats and compare them.  If their genitals look similar, they're the same sex, if they look different, they're different sexes.  You can separate the whole litter this way  Here is a link to another forum, which has an AMAZING amount of photos on sexing baby rats (thanks to Estelle for those great pics!)  Until it actually becomes a page, the thread will have to do.  Good luck!

http://www.ratpalace.com/mwforum/cgi/topic_show.pl?tid=6887&hilite=sex#68453

[Yresim]

I was able to tell mine apart the day they were born.  All you need to do is compare the two very carefully.  =)

It is possible that your friend has 2 females on her hands (in which case, the other might be preggers), or that you have a male & a female (in which case, you should separate them, or spay/nueter one of them).

Good luck!

[amymckee]

My first rats were girls, then boys, then girls.  

What throws people off is that they are looking for the wrong thing. They both have a "penis", but in girls its actually their urethra (I think?). Its whatever they pee out of.

You need to be looking for testicles, which are very obvious in male rat. If you can't see any signs of them at like 4 or 5 weeks, they are most likely girls.

[Suebee]

And female rats have nipples -- males do not.

[SCRAPPYSMOMMY]

Even with day old babies, it is quite easy to tell them apart.  The first major noticeable difference is that looking closely u can see three openings on the baby females.  also, the anal and urethral openings are close together in a female baby, but spread furthur apart on the male.
By about 5 days old. or as soon as the fur begins to come in on the tummy, it is quite obvious that the females have 10 little round circles of bare skin where their nipples will be.
As they get older, these easily recognizable differences become vague for several weeks.  The differences become prominent again by about 4 weeks of age when the males testicles drop and become easily visible.  But there is no mistaking adult males and females.  Unless of course the male is neutered.