National Geographic examines the incredible size, speed and strength of some of the worlds biggest bears the polar bear, brown bear and black bear. All native to North America, these formidable creatures can weigh more than 1,000 pounds, outrun an Olympic sprinter and take out it's prey with a single bite or swipe of the paw. Watch as National Geographic uses science, including MRI imaging, to deconstruct these bioengineering marvels to reveal the secrets behind the largest land-dwelling carnivores on earth ultimate bears.
