And there are Grizzly bones found often. As a hunter, I have found them. Even if I only found one, that is one more then have been found for Bigfoot.
Bigfoot might not be an animal but a form of human—as such they night be smarter than we are and as such hide from us, bury their dead and perhaps use the ESP they have to render themselves invisible! They only are sighted when they are sick or make mistakes. We might be their form of entertainment —they watch us for fun. As totally psychic animals they know when we are looking for them before we even start—having ESP they are ideal hunters and do not need the so called advances of civilization. Far fetched? Yes, but possible.