Grizzly Bears: The Fierce Predator of the North | Nat Geo Wild

Furry and adorable, or fierce and aggressive? Like many animals, the grizzly bear can be all of the above. These beauties of North America are a subspecies of brown bear that once roamed large areas of the American West. Though still common in Alaska and western Canada, their population has dwindled in the lower 48 states with their home ranges in rural, isolated locations. Their habitat varies widely from dense forests to alpine meadows to open plains and arctic tundra. Grizzly bears' home ranges span up to 1,000 square miles. They wander the land foraging and hunting, their meals dependent on the season and food availability. They are predators at the top of the food chain, though much of the grizzly bear diet consists of fruit, roots, grasses, and insects. A hungry male can consume up to 40,000 moths in just one summer day. In fact, a number of the grizzly's physical characteristics center around finding and eating their meals. Grizzly bear claws are longer and less curved than those of the black bear, making them well-suited to digging up plants or rodents. And with a nose more sensitive than a hound dog's, grizzlies can detect food from miles away. Their distinctive hump is a large muscle mass that adds strength when digging. It is also one of the distinguishing differences between grizzlies and their black bear relatives. Running at 40 miles per hour, adult grizzlies are nearly twice as fast as the fastest humans. This speed is essential when grizzlies hunt larger prey like elk calves. Grizzly bears scavenge constantly for nutrition, especially during hyperphagia, a period of two to four months when grizzlies can gain more than three pounds per day to prepare for hibernation. During this period of winter rest, they'll live off the layer of built-up fat, not needing to eat, drink, or release any waste. Over the winter, a grizzly bear can lose 15 to 30 percent of its body weight. They'll emerge as the weather warms and food is again plentiful. But for females who were pregnant before hibernation, they won't be alone come spring. For during the hibernation period, they will have given birth, often to twins. And the three will venture out into the wild together, mother and cubs in tow.