OK. I grew up on a farm where I saw plenty of mice and other wildlife that is known for hiding. I never saw a rat nor any evidence of a rat.

EDITED to add: We had cats which killed mice and gophers and birds and voles and all sorts of creatures. I NEVER saw a rat. I know it is hard to believe, but Alberta really is (at least mostly) rat free.

Rats are the one pest that are almost unafraid of humans. Once upon a time, I lived in a wooden cabin that rats had found a way into, via holes cut in the floor for pipes by the kitchen sink.

Late in the evening, one would pop up. I could get up to chase it away, but it wouldn't flee until I got close, and it would pop out again a few seconds later. It knew it could out-wait me and there was little I could do to stop it that night. Trying to block the hole merely meant they ate away the wood around the hole, until they could get back in again.

Mice aren't a problem at all. You don't want rats.

If you've got a rat infestation in your building, it won't take long to figure it out even if you never see them. They have a tendency to cause a lot of damage and leave their shit all over the place.