That does sound like what I remember of cotton rats. They always seemed
like a 'cute' version of a Norway rat. In my memory (which is no longer
reliable) they were maybe a bit smaller, pudgier. w shorter tails.
I don't have a field guide to mammals, & quick search of the web didn't
turn up anything really useful for IDing/comparison. Unlike other
categories of critters on the web, everything easy to find had to do
with killing rats. Maybe try taxonomy.
> Very similar to the size of a healthy Norway rat. However, it didn't have the 'mean' look of those. The head was more rounded and the body a bit more oblong; the hair was smooth and tight, a bluish gray on top and a white on the belly. Norway rats have more of a sharp-featured face with more prominent ears, coarser hair and a rangier build.