Realized I should have put more information Shows how much I know about forums.
I adopted my adult rat Bear from the humane society. He is a fat, white rat who is extremely affectionate and was cuddling with me upon the first night of his rehoming. We had him living by himself only for a little bit because that's how he adopted him--he was living by himself in the shelter and we didn't want the stress of rehoming to be combined with additional stress from meeting a new cagemate.
Since then we have adopted a baby dumbo rat named Taco who is still very skittish. we are having trouble introducing him to Bear, but i'll post a whole long threat about that : )