Over a thousand pounds, more than four feet tall at the shoulder, sporting four-inch claws and paws that can dwarf a lion's... the world's biggest bears are the largest land-dwelling carnivores on earth. Any of the North America's 'Big Three' bears - polar, brown or black - can take down just about any animal they want, including human beings. And that's only part of their power: they can run as fast as horses and faster than Olympic sprinters, smell seals hiding under feet of snow and bite through thick tree branches. And they're smart enough to get just about any food they want anywhere they find it. National Geographic goes one-on-one with this biological juggernaut and deconstructs its formidable combination of massive brawn and unbelievable powers of smell.
