Oh, my! Do you live near water, Eileen? Rats like water.
In our previous neighborhood, where we rented a single-family home, there was a creek that ran behind the houses across from ours. Rats were plentiful there, often finding their way into homes along the street. A neighborhood gathering always led to conversations about rats in attics, garages, etc.
Right now, we have what sounds like a mouse in our attic. Doesn't sound large enough to be anything else. I am going to call Critter Control. Other townhome units here have had squirrels build nests in attics. Hopefully, that is not the case with ours!