Google "Gigantopithecus." Bigfoot existed once - the only debate is whether or not it still does.
Anthropologist friend told me that early man definitely disposed of corpses in a ritualistic manner - sometimes burying, sometimes burning, sometimes submerging them. If Bigfoot is doing this, bones might be hard to come by.
It was his idea that Bigfoot was a primitive hominid that saw people (us) as hostile. Like other primates, he would tend to move away from populated areas, but if someone intruded into his territory, he would likely make a display to chase them off, either howling or a visual display, like standing up, just like gorillas and chimps.
Every time I read about a Bigfoot encounter there is activity that generally follows the above pattern. You really can’t expect them to just walk into your camp, sit down by the fire, and join you in a chorus of Kum-by-ah.