I've seen snakes (ewww), herons, owls, and turtles. Once, on an early morning ride, I rode a wooded path with a herd of deer running on either side of me! I was fearful one of the pack would decide to dash in front of me, but none did and it was the most fantastic thing I've ever experienced on a ride.

I have lived and rode in Southern Jersey most of my life and had never seen a groundhog until a few years ago. Now, I virtually have to thread myself through them along the paths. It seems to me to be a sad statement about over-development.
BTW, I love the photos on this thread!