New Rat Bite me, Blood

Question
A week ago I was at the pet store and saw the owners unloading a bucket of feeder rats they got in. I know that feeder rats don't make the best pets but one of them was staring at me and I picked him up. He was very friendly and was crawling all over me and cuddled up by my hoodie and fell asleep. I offered to buy it as a pet, but the owner told me they were meant to be feeders and might be aggressive. I got him anyways.

Over the next few days he bonded very closely with me and would cuddle up in bed and enjoy being petted. He was very loyal. But today I heard him whimpering for some reason and I am not sure why. Right now he is housed alone since my other rats are female and I don't want him to breed with them. So I picked him up to comfort him. About a few minutes of petting he bite me really hard and deep on my thumb. There is a lot of blood and the bite really stings. He started to try and bite me again. I am not sure why he changed his character so fast.

Help?

Answer
Dear Stan,

The most common reason for a sudden behavioral change, aggressiveness, and biting in rats is pain. Especially since you heard him vocalizing, which isn't something rats do very often. You need to bring him to the vet right away. He may be in severe pain.

You also need to get him a male friend. As young a one as possible. Having no buddy also makes a rat skittish and scared. He needs the comfort of a friend by his side 24/7.  

I really hope he is OK. If the vet gives him a clean bill of health, and you get him a friend, and there is still a problem, you need to ask yourself if there could have been some sort of trauma to freak him out.

Best of luck and health to him.

Squeaks,

Natasha