It's a beaver! It's an opossum! It is not either of those things. It's a groundhog!
Groundhogs are a part of the squirrel family. Usually they are seen on the ground, but they can climb trees and swim. They live near woodland and grassy areas. Chances are there is a stream nearby as well. Groundhogs dig burrows underground. They use burrows for sleeping, having babies, and hibernating. Burrows usually have more than one entrance or exit, so that the groundhog can escape if necessary.