Squirrel tracks

My driveway seems to be the best place for photographing animal tracks. We had another fresh dusting of snow and I found these tracks this afternoon. This set belongs to a neighbourhood squirrel (most likely a grey squirrel). I have two types of squirrels in my yard, and I don't know how to tell the difference between their tracks.

This squirrel was heading towards the left of the photo. As squirrels run they place their back feet on the ground just in front of where their front feet have been. Rabbits do this as well. If you are trying to differentiate between squirrel and rabbit tracks, you can follow them to see if they lead to the base of a tree and disappear!

You can tell how fast an animal was going by how far apart the sets of tracks are. Close together, the animal was going slowly, farther apart and the animal was running. There is only one set in the photo, the other set was far enough away. I think the squirrel did not want to hang around on my driveway for too long.