He kind of blew that gorilla vs. polar bear question. He like, kinda sorta gave the edge to the polar bear. Listen you guys, I know a thing or two about animals. I do. And I have been having this debate with myself and others for literally years. Which animal is the toughest? Which animal would win a fight. Blah blah blah.
The very best way to judge a mammal's toughness is by the prey that it eats. How large, in comparison to its own body, is its food? Let's see here. Put aside the fact that the largest silverbacks weigh 500 pounds and polar bears weigh over a ton. Polar bears eat fucking seals. 300 pound predators in their own right. Gorillas eat bananas. End of story. It's huge claws and teeth and millions of years of killer instinct bred into an animal versus a really strong monkey that eats fruit. It's like pitting a boxer versus a bodybuilder in a fight. There's no contest. Especially if the bodybuilder weighs 1/4 what the boxer does. Dumb question.
Oh and if you're interested, pound for pound the two toughest mammals in the world are the wolverine (60 pound animal that preys on elk and has been known to fight off grizzlies) and the least weasel (the world's smallest mammalian predator, it eats rabbits like 8 times its own weight), with the honey badger a not so distant third. Honey badgers have been known to attack and kill male lions by biting off their nuts. Real fucking talk there. Peace, lion nuts.
p.s. And if you're curious, no animal on earth (outside of a few snakes) can kill a full grown bull elephant. But that's only because they're so much freakishly larger than everything else.