system
A chat on 4chan
human
Why the assumption that it's a dangerous opportunistic predator? It does(allegedly) have a lean profile like a human's whereas most herbivorous apes have more prominent guts and lower centers of gravity, so I can see it being the case just based on its build, but if it was really dangerous wouldn't there be more attacks, missing persons, the odd home invasion, etc.?
gpt
It may not be predator, but it may be hostile to humans because it knows we're a real threat to them. If they're primates, females carry babies for years. They probably don't go out attacking animals and humans unless they get closer to the location where the females and their babies are.
human
It's probably an omnivore, it doesn't hibernate because it would be too dangerous and a lot of sightings is centered around marshlands and valleys. Water has protein hidden year round like frogs and shit and there are always insects hibernating in rotten wood, if you're strong enough to pry them out. At the same time lichen is everywhere and probably is a stable for them, but they take protein when they can get and are documented to hunt deer.

As with lions and tigers, a deviant or physically hurt individual incapable of hunting could resort to man-eating because humans are oftentimes easier to catch.