This isn't a true FAQ, but if you read through all of these, you'll probably find something you always wanted to know about rats. Rats have poor vision. They also don't see in color.
Rats normally prefer to have cage mates.
It is possible to group female or male rats together, though care should be taken when introducing a new rat. Female rats are very curious, and love to explore and play games. Both genders make great companions. Rats can eat chocolate. Rats can also eat smaller pets.