There are five or six squirrels living on the property and I'm friendly with all of them. It's easy to make friends with a squirrel: just offer him a peanut. I do this all the time so the squirrels like and trust me. They'd never run away when they see me. But one thing they do intrigues me.
When I encounter one of them during a walk, he'll stop and stand on his hind legs, facing me. This position is maintained for about 30 seconds and then he continues on his way. This happens all the time. I swear they're telling me, "Thanks for the peanuts, big guy." I can see it in their stance: this is an expression of gratitude.
PS -- Squirrel facial expressions are complex and amazingly cute. I wish I could take a photo of my main squirrel friend but he's wary of cameras -- he's probably seen too many guns. We humans can be dangerous critters. Anyway, they're very cool. Anyone else made friends with a squirrel?