Well if it bit you, then you'd know it wasn't so people friendly lol. Most rats that bite a human will jut give a nip and nothing more. Because Frisco thought he was attacking Icarus, he was vicious, and grabbed and tore, not just a quick nip at all.

A biting rat is probably the only way to tell if it's going to be nice or not. I've never heard of a rat being nice and then suddenl;y turning mean unless it wasn't treated properly.

Even if you do buy a rat that isn't very nice, it isn't very hard to convert it with love, and gentleness.....and food...