I have a 1 1/2 yr. old male, biege, huge, rat named Casper. And 2 black females named tipsy (because of the white tip on her tail) and Cheese. They are really smart. but since I got them from my stepdaughters litter, I trained them to be nice myself. Her rat had 10 babies, and when we had a litter over here, there was 13 of them. Amazing how so many babies can be in that little tummy of theirs. At the time we had a litter, the shops had like, no rats at all, so they took them. And my daughter got sold a pregnant rat, so they had to take the babies. No one ever mentioned freezing or any other thing that might happen to them. So that was good of them not to tell her. If they didn't take them, I probably would have alot more rats now.