Well, the store is what called it a rat pup when I bought it. I'm still a noob in the hobby, so I'm still a bit confused about the terms used to describe feeder rodent size.

I just did a quick search on rat pup, and this little guy is definitely bigger than what I'm seeing. It's hard to tell without a scale to measure its weight (scale is coming later this week), but I'd guess that it is either a small or large weaner. Is this still too young to try to keep as a pet? My son is only 3, so I'd prefer to get him separated from the rat before he gets too attached, if it is going to die on him.