Spencer
Unless you're in the UP, it's not a Wolf. Of the big critters we've got in West Michigan, your choices are Cougar (the DNR will only say they haven't seen one), Black Bear, Coyote and Dog. Bears aren't as uncommon as you might think and could show up in your drive if moving or looking for food. With the weather as it's been, the bear should be starting to move around. But, I don't think it's a bear print. That leaves Coyote and Dog. Biggest Coyote I've seen is about the size of a small German Shepard. I'd guess along with the rest of the guys-- Dog. Any neighbors got Great Danes?
SHF