Rat or Not Rat?

And why do I care what made the burrow?

I’m always on the lookout for interesting holes in the ground. Sometimes they are opened by water eroding the substrate (earth or concrete), sometimes by a tree tipping over or a heavy truck damaging the sidewalk, but other times animals do the digging. And nothing stops animals from using holes formed by inanimate forces, like a squirrel exploiting a r…