I live in a town that has about 400 people within its hold. There is a school, a post office and there was place to get gas and grab a candy bar, but it’s been destroyed. Hopeful for a new one. A town you have to drive 15 miles to the store for food.
But in this very little town there has never, ever, been squirrels. Never.
One person 20 something years ago brought some in, hoping that they would stay. They died.
Last night thou, my dogs barked at a tree like a cat was up it. My husband and I saw nothing.
This morning, they started barking at the other tree and guess what. A squirrel. We have a squirrel. 
possible-chaos 