The large man in that picture is Hafthor Bjornsson. He’s a professional powerlifter and one of the strongest men on Earth. He’s nearly 7 feet tall and over 400 very solid pounds. The smaller guy is Conor McGregor, one of the best MMA fighters in the world, he’s MUCH smaller than Hafthor, but a much more skilled fighter. But, guess what? Hafthor would absolutely smash him if it came to it, because at a certain point the size and strength differential is just too much. Hafthor is over a foot taller and nearly 3 times as heavy, if he gets a hand on Conor, its game over.
However, Conor is in nowhere near the world of shit the BJJ fighter is.
That’s a pretty average guy standing next to an “average” grizzly bear. I’d guess that guy is about 6 feet tall, say 200 lbs. Your average adult male grizzly bear can stand up about 8 feet, and weigh over 1,000 pounds. Grizzlies can get bigger, but that’s a good average. Additionally, there’s no reason to think a grizzly isn’t substantially stronger than even Hafthor, and he’s not average. There is a video of grizzlies knocking 800 lb dumpsters around like beach balls, and that’s when they’re just playing. A truly pissed off grizzly’s strength would be terrifying, and frankly I’d never want to try and test just how strong they can be.
The bottom line: even a world class BJJ fighter is completely, utterly out of his depth here. Hell, imbue Hafthor with world class BJJ skills, and he’s still going to die in this fight. A grizzly bear isn’t another person and BJJ training, unless I’m seriously missing something, doesn’t focus on grappling bears, and bear anatomy is a bit different, not to mention much tougher to hurt.