male rat killed other male rat

Question
My son had two male rats of the same size and yesterday morning he woke up to find one of them dead from a big chunk out of his mid section. The male left is now biting any hand that comes in the cage and drawing blood. What can  we do with this rat. My son is afraid of him now and we are afraid to put another male back in. Do we have him castrated or do we find him another home. Help.... The rats are the kids thing not mine but I do help them.

Answer

This is uncommon but if there is aggression, this is could happen, unfortunate as it is.  How long have they been together?  How old are they?  Where did you get them from?
Did they fight alot before this happened?

Sometimes a rat may die from natural causes and the duty of the surviving rat is to consume the remains. This is part of a wild trait because in the wild, it is an honor to consume their mate rather than leave their remains for predators. It is common for this to happen even with domestic rats, as disturbing as it is to us.  Sometimes people think the other rat killed the dead rat, esp if aggression was not seen before.  He may be upset due to the death of his cagemate which is causing him to bite....but again, unless someone saw a fight or they have had some serious fights before, the survivor could have killed him during a fight.  

The rat is truly freaked out, I can tell you that, and its understandable that you would be scared of being bitten yourself. Its best not to show fear though or it makes it worse. I know, easier said than done.  

I suggest neutering him right away if he is going to lash out and try to bite since we dont know for sure what really happened between the two rats.  Forget another male with him for now, at least.  You will need a good vet to neuter him (If you need one please let me know and I will give you some names once you let me know your location)  I have had aggressive males neutered and they turned into sweet souls.   

I would not find him another home. This wont resolve anything. It may only confuse him more and cause even more problems for him that could result in him ending up at some shelter with no place to call home. I always say that when we take on the responsibility of a pet, regardless of the species, they are ours to love and care for, regardless if we end up with a bad seed.  I think with neutering him and lots of patience, he will be just fine.  Again, I have had this happen to my own rats and also taken care of plenty of aggressive rats that were inbred (which is probably the case here if he truly killed his mate) and neutering solved the problem. Keep in mind it takes a few weeks for hormone levels to drop though, so dont expect to see big changes for a few weeks post op.