That is very puzzling. You would think that if it was a mountain lion there would not be such a big opening, but who knows. I do not necessarily believe in bigfoot, but I watch monsterquest on the History Channel and they did talk about finding "nests" in thickets that they thought were used by bigfoot.

My best guess though would be a mountain lion. I live in southwest MN and someone saw a mountain lion go through the land that I deer hunt. I never saw the cat or tracks, but I talked to a guy who traps there and he told me that he found cat tracks down by the creek. I definately do not think that a coyote would do that. I have heard of people digging up coyote dens and finding as many at 75 fawn skeletons inside of it, but that was an underground den.