Rats go into heat every 5-7 days, I think. I know it's not every 3.

You'll know a female is pregnant after about a week from first introduction to the male. He'll usually mount them all the time they're in heat, which is weekly. If it's been about a week and he's not mounting, good chance they're pregnant. I have had my male try mounting my girls about a week before they give birth, but by then they're usually getting nice and fat.

You should get babies 3-4 weeks after you first get them. Rats aren't sensitive to things like a day cycle like mice.

I also wouldn't separate the group at all, unless you want to keep the male from breeding with a certain female (like a daughter).


Any thing else?