Sexing issues

[Fionax]

Ok so I thought I knew how to sex a rat, but I am a little concerned that I might have missed something on one of my new babies. How old was it that a males testicles were prominant enough to be easy to tell? And how difficult is it before that to tell?

The reason I ask is that one of my rats have been acting really weird. Like, she does this biting thing to the other girls that makes them freeze up and their ears vibrate... and then she jumps on their backs and does a movement that I can only describe as humping on crack. It is really weird and since I don't know how rats have sex, a little scary. We don't want to isolate her simply because we don't know what is going on... but we also don't want rat babies. So um... Any clues to what this behavior is? And as for sexing the rats, someone please explain it to me, since I could possibly have not learned the correct way to do it.

[blueorchid]

No advice on sexing babies but I do know that females will even "hump" one another.

[DorseyClairebelle]

Female rats will hump each other when they're in heat (especially the alpha girl), and sometimes you can see them actually vibrating all over (but I don't know about the biting thin...).  So don't assume that that means one may be male.  Testicles generally drop at four weeks of age, although it has been known to happen later than that (I read about one where a male didn't show his until he was EIGHT weeks old!) but that's pretty rare. By the time they're a bit over a week old you can generally see a hint of them.  To check and make sure, here's a link that's helped me a lot (one of my girls just had a litter):  http://www.ratz.co.uk/sexingrats.html .  These pictures make it pretty easy to tell.

Hope it helps!

PS:

a movement that I can only describe as humping on crack.

---> 

[Fionax]

Ah thanks you guys... that makes me feel better. I was right about her being a famale then, because she obviously doesn't have testicles. .... I just didn't know that they would do that. Like my BF said "Oh so we just have a lesbian rat then..." 

And thanks for that link Dorsey, it put my fear that I was an idiot to rest. I apparently did learn how to sex a ratty correctly, I was just weirded out by Rika's behavior. I will save it for reference later