The grizzly bear, formally classified as Ursus arctos horribilis, is the North American subspecies of the brown bear. Found predominantly in the northwestern United States, Canada, and Alaska, this omnivore represents one of the continent’s largest terrestrial carnivores. This exploration provides the specific measurements necessary to grasp the sheer scale and physical presence of this iconic species.
Shoulder Height and Standing Reach
The most common way to measure the size of a grizzly bear is by its shoulder height when the animal is on all four legs. Adult male grizzlies, known as boars, typically stand between 3 feet 6 inches and 4 feet 6 inches (1.07 to 1.37 meters) at the shoulder. Females, called sows, are generally smaller, with a shoulder height ranging from 3 feet to 3 feet 8 inches (0.91 to 1.12 meters). The bear’s prominent muscular hump over its shoulders contributes significantly to this measurement, distinguishing it from other bear species.
When the grizzly stands upright on its hind legs, its size becomes far more pronounced, offering an imposing vertical reach. An average adult male can stand between 8 and 9 feet (2.4 to 2.7 meters) tall. This standing height, which includes the length of the head and the upward reach of the front paws, can sometimes approach 9 feet 9 inches (3 meters) in larger individuals.
The bear’s ability to stand bipedally is primarily used for surveying its surroundings or displaying dominance, rather than for sustained movement. This tremendous reach is compounded by the length of its non-retractable front claws, which can measure 2 to 4 inches (5 to 10 centimeters) long.
Weight and Overall Body Mass
Interior adult male grizzlies in the contiguous United States generally weigh between 400 and 600 pounds (181 to 272 kilograms). Adult females typically weigh between 250 and 350 pounds (113 to 159 kilograms). This weight is distributed over a dense frame, characterized by a thick layer of muscle and fat.
The total body mass of a grizzly fluctuates dramatically throughout the year, driven by the necessity of hibernation. During the late summer and fall, bears enter a period known as hyperphagia, where they consume vast amounts of food to prepare for winter. They can gain up to 3.6 pounds (1.6 kilograms) per day during this feeding frenzy.
Before entering their dens, a large male grizzly can weigh nearly 800 pounds (363 kilograms) or more. The stored fat reserves are metabolized throughout the winter, and the bear may lose up to 30% of its total body weight during its four to seven months of denning.
Size Differences by Sex and Habitat
Grizzly bear size is heavily influenced by two primary factors: sex and geographic location. The most consistent difference is sexual dimorphism, where adult males are significantly larger and heavier than females. This size advantage helps boars compete for breeding opportunities.
Geographic variation accounts for the greatest extremes in the species’ size. Grizzly bears inhabiting interior, mountainous regions, such as Yellowstone, tend to be smaller due to a diet that is more plant-based and less abundant in high-calorie prey. In contrast, coastal populations, often referred to as Alaskan Brown Bears, grow to much larger sizes.
The abundance of high-protein, high-fat food sources, particularly spawning salmon, allows these bears to attain maximum size. Coastal males can average over 850 pounds (385 kilograms), with some exceptionally large individuals occasionally exceeding 1,200 pounds (544 kilograms) before hibernation.