It's called Missing 411: The Hunted. It's on YouTube. It's about people going missing in or near national parks under unusual circumstances such as no signs of foul play or wild animal activity.
The second to last story spooked me. They played a recording of an unidentified animal making scary noises in the woods. It was recorded by hunters hiding in their shelter and when the hunters would make noises in response to the animal, the animal would mimic the humans. I don't know why it scared me, it's really not that bad. I feel kinda silly now.
I live right off of a poorly lit semi-wooded walking trail and two times I have been startled on that trail at 3am when I take my dogs out to go potty before work. Once, I turned around to find a man just a few feet away from me but walking away from me. I didn't hear him come through the trees and he didn't pass me from the front so where did he come from? It is possible that he was walking toward me and turned around when he got a few feet away from me. Maybe I spooked him too, it's not a well lit trail.
The second time, I saw two tall, light colored, extremely skinny, bipedal things walking slowly down the trail in the dark. They were not people, they didn't appear to have arms and they were way too skinny to be people. I told my friend about it at work that day and she suggested they were cranes (tall skinny birds) but only owls are nocturnal. Staying quiet at night is a bird's natural self defense, there's no way a pair of cranes would be walking down a trail in the dark. The only thing I can think of is that I was seeing two deer facing me head on from the front and maybe they were walking diagonally or on a diagonal path from me which gave them the appearance of being bipedal and walking slowly but I'm not sure. I stared at them for several minutes until they walked out of view and I just couldn't figure out what they were. Nothing makes sense about what I saw. It was really creepy. I take my dogs out to the street to go potty now. I don't go on the trail in the dark anymore. I think the documentary just reminded me of those times.