Grizzly Bears are large brown bears that live in cool mountain forests and river valleys. These solitary mammals can run up to 35 mph (56 kph) for short bursts. Grizzlies are a threatened species.
Anatomy: Grizzly Bears are up to 7 feet (2.1 m) long and weigh up to 1,500 pounds (680 kg). Females are about 2/3 the size of males. Their thick fur ranges in color from black to brown to reddish brown to blond. They have dense fur close to the skin and long, coarse guard hairs that become silver tipped as the bears age, giving them a grizzled appearance (and their name). They have a big head, a long muzzle, and a large hump on their shoulder (a mass of muscles that give the front legs extra
strength). Like all bears, they are plantigrade (flat-footed). The front claws are up to 4.75 inches (12 cm), almost twice as long as the rear claws. Newborns weigh only about 1 pound (0.45 kg), the size of a rat.
Behavior: These fierce predators are mostly nocturnal (more active at night). Although they sleep in dens (caves, hollow logs, or holes they dig) during the winter, they are not true hibernators and can be easily awakened.
Diet: Grizzly Bears are omnivores who eat plants, roots, berries, fungi, fish, small mammals, and large insects.
Classification: Class Mammalia, Order Carnivora, Family Ursidae (bears), Genus Ursus, species arctos (grizzly bear and brown bear).