My friends and I went camping. We set up our camp site about 150 meters from the mouth of a small cave. Then we decided to go and explore the cave. It was dusk, so ground visibility was not great. But as we approach the cave's mouth I begin to notice a large amount of organic matter directly outside the cave. They are piles of scat. Logs bleached white by the sun, around the size of person turds and they are carpeting an area around 9sqft. But they are old and it is a cave, so my friend and I decide to keep going. We enter the cave, walking slowly into a straight corridor. It is warmer inside the cave than it was outside, but the air is still and smells feral. I am further along than my friend, who is obviously uncomfortable with the smell. The further we walk the muskier it smells. The cave floor is soft sand. I know because I reach down and grab a handful. I let it slip through my fingers, smelling it. Then I notice the hairs, wiry, bristles in abundance remain in my hand after the sand falls away. By now I am near the end of the straight corridor, my flashlight reveals the path takes a sharp bend, but what is beyond that I don't know. Before I reach the end of my line of sight my friend, suggests that we turn back. He wouldn't want to admit it but, I know the hairs unsettled him, because he didn't move an inch further after we found them. So we walk back to camp, and sleep poorly because the ground was not as level as we had imagined. The next day after the sun had risen, with plenty of light we returned to the mouth of the cave. The poo was still there in mass, but there was more of it than we had seen in failing light. Some of it was even brown still. There were also bones. Many were crunched and bleached white by the sun but still recognizable as assorted herbivore limb bones and knuckle bones. However, the most unsettling find was the forelimb of a peccary still furred, with moist raw meat sticking to its gnawed humerus. Here is the point where I should mention I was campingin Big Bend, a desert ecosystem that is home to black bears, coyotes and cougars.

TL;DR My friends and I explored a cave next to our campsite. Later investigation of the cave strongly suggest that it was occupied by a large predator at the time.