The key to learning where they can be studied, such as it is, is to stop ridiculing habituators. It's not just the scoftics and denialists, honest skeptics and outright believers who insist on "ape camp" thinking are just as much part of the problem when their rude jabs drive away the very witnesses that have the information that could solve the puzzle.
Quite a few years ago now a researcher suggested we'd be ahead to look at cultural anthropology instead of wildlife biology. That is insightful even today but it was radically insightful at the time and drew no end of ire. I agreed then, I agree now. The behaviors I've experienced are not the behaviors of mere dumb animals. There's a gray area inhabited by big, hairy, seemingly technologically primitive, but otherwise quite sophisticated bipeds.
We can't see them because on the whole we refuse to look where they are, we only look where we dare to find them ... in the confines of the paradigms we're comfortable with.
MIB