I believe that there is nothing so crazy that it can't be true. That said, with folks on this continent having a penchant for "varmitting", which is a politically correct word for "shooting anything that doesn't require a license because...well I like to shoot stuff", it's absolutely incredible that one hasn't been brought down yet if the Yeti/Bigfoot/giganthropithicus actually exists.
Can they be SO good at hiding that they have avoided all rifle fire since the first white "Americans" and "Canadians" settled here a few hundred years back? The only explanation would be that they only come out of whatever holes they hide in during the night, and even then, with that availability of extremely high performance light enhancing and even thermal vision systems, the odds of one being spotted and then zipped - astronomical against.