I entirely agree, FWIW. Exactly correct from what I have read also. With grizzlies, play dead, you don't stand a snowballs chance anyway. If he is going to kill and eat you, it's gonna happen no matter what you do, short of a gun and possibly OC spray. Most likely he is attacking as a warning. As long as he thinks you are a threat he is going to toss and chew on you. If a Black bear makes contact fight for your life, it is most likely a predatory attack. And yes, you can bluff a black bear. A grizzly on the other hand, like a polar bear knows he is the baddest thing out there so bluffing, in my opinion would likely appear to a grizzly as a challenge. A challenge, I might add, you are woefully incapable of backing up.