Rat Bully.

Question
Hi there, My wife and i got our first pet rats just over a week ago now, both males about 5 months old, they were rescues that we got from our local pet store. The larger one is called Brain, he is an agouti and the smaller one is Pinky, a fawn. The day we bought them we got them settled for about half an hour and then they started fighting for dominance which we new would happen but we didnt expect it to be so vicious. Brain obviously being bigger is the dominant one and pinky came off a bit worse for wear with cuts to his tail, ear and foot, all have healed up now. Brain is our problem though, when we let them out he's itching to just go everywhere but wont let Pinky come with him, he hunches his back and forces Pinky away with his backside which then turns into a fight. This behaviour happens every time we let them out and Pinky is visibly nervous of Brain and is getting really stressed, they are fine when they are together in the cage which i find odd. We cannot handle them, we get too stroke them but have to be very gentle, Brain has bitten both me and my wife and drawn blood so it makes handling even harder. In the pet shop they were living in a group of about 10 and were fine to be handled. I'm thinking of getting them neutered to maybe lose some of that testosterone thats flying about. Any advice you could give would be much appreciated, i know adjusting takes time but i want them both to be enjoying life with us. Thanks.

Answer
Neutering should definitely help.  Most males are aggressive because of the testosterone and removing their testicles can cut down on that a lot.  If the boys are constantly fighting, you may have to separate them at least until after they are neutered and have calmed down a bit.  Fighting males can easily hurt or even kill each other if they bite in the right spot.

Hopefully the neutering will stop him from biting you and your wife.  If not, there isn't a lot you can do about it once a rat decides to be aggressive towards humans.  The fighting may be causing him to stress out as well, which may be contributing to the aggression.  How large is your cage?  Sometimes if the cage is too small the rats feel like they don't have a space of their own and it can cause territory battles among males.  The general rule of thumb is 2 cubic feet of space per rat, but you may need to go larger if you think they need more space.

Well I hope that helps, good luck with your rats!