Put out some steel traps on a little private land I can trap last weekend, and had one stepped on but not tripped, and one dug up today by coyotes; they are really hard to catch, when you get one you will feel like you accomplished something, at least I did.
Again, I'm not the expert, but from listining to those that are, the trapped tripped could be a beaver with large feet. they won't hit the pan right, or could be a bobcat, as they and for the others, want some fresh meat.