Rats love company. You should have at least two rats together in a large enouf cage.(about 2-3 feet per rat)When you adopt your rat the best thing to do is to get one of their sibs. That way you wont have to worry about introducing any new rats to an older rat. If you have an older rat that has been by them selves for quite a wile. Then you should leave that rat alone. The older they get, the more set in their ways they get.
Rats love to play with you every day. Try spending at least an hour with them every day. They will love you for it.
Rats don't usually bite. It is very unlikely to be bitten by a rat. The bites I usually get are love bites, they never hurt. As long as you play with them everyday you will have no problem. They are lovers not fighters. Even with all of this it is still possable for a rat to bite hard. I have only been bitten once, and that was my fault that I got bitten. I didn't pay attention to what I was doing. Other than that one time I have never been bitten, but I always get licked to death.
Rats do not spread rabies. To spread rabies you need to be bitten with saliva being added to your blood stream. Rat's teeth are set in front of their mouths and are dry.
A group of rats is called a mischief. Get four of them together in one spot and you'll know why.
Rats sneeze alot. Nothing to wory about, it's normal.
Rats can get "nose bleeds" from time to time. This usualy isn't too much of a concern, but if it gets to bad then you need to seek a vet. It is caused by stress or illness.
Rats cannot see color.
A clean rats fur smells like grape soda.
You can train a rat to do tricks. If you have the rat for awile you will notice that he is training you to do tricks to.