We Found This Paw Print While Four Wheeling – What is It?

I went with some friends of mine four wheeling on the ATV trails in Waterford and we ended up at the top of a mountain where we found this paw print. It's not a dog's and it's much bigger than a cats. What is it? 

We aren't even sure what mountain we were on, but you could see a good chunk of western Maine and New Hampshire, all the way from Shawnee Peak in Bridgton to Mount Washington. It was an amazing view that this picture doesn't do justice. Tap or click it to get the high-res version.

While I was taking this picture, one of my friends point out the track in the dirt. I put my foot next to it for some perspective on the size.

It can't be a dog because there are no nails. We've had all kinds of guesses...cougar, bear, bobcat, mountain lion, but we aren't sure what it might be.

Any guesses? If you've got some kind of outdoor wildlife experience, you'll get more cred than anyone just guessing, but we like guesses too. Let us know what you think in the comments below or on Facebook and Twitter so we can solve this mystery.