My son has a Mastif. They live at the edge of a small town in northern Illinois. It's a rural area with lots of corn fields.
Anna is usually very good, but one night afer a rain, she wanted to run. She ran into a field behind their house and romped for over an hour.
The next day my son got home from work to find dozens of people in the field behind his house. He asked the neighbor what was going on and the neighbor told him that a mountain lion had been sighted the night before and they were tracking it and making casts of the tracks.
My son told them "Um... I think it was Anna."
They argued with him. Someone swore it was defintely a mountain lion. Someone else claimed to have seen it.
My son looked at the tracks and told them that they were dog tracks, not cat tracks.
To this day, SOME people believe that it was my "granddoggy", some are convinced that mountain lions live near us.
All that aside -- we own thirty acres that we try to keep wildlife friendly. We have lots of deer, turkey, pheasants, fox, and, yeah - coyotes (those bastards!). Several years ago we saw what we can only describe as a black panther. We found one print. It was a cat.
The animal we saw was huge and it was black. Was it a panther? Don't know for sure...
We've never seen it again - but several neighbors claim to have seen it since.
I'm not afraid to let the kids camp. This cat was running to get away from us. Coyotes don't come close (they know that we will shoot them).
The scariest experience I've ever had down there involved deer scaring the shit out of me... Oh, wait - once I ran into a human who didn't belong there. He was scary! I put the run on him pretty fast...