The grizzly bear, Ursus arctos horribilus is a subspecies of brown bear that lives throughout North America. Despite their terrifying reputation, grizzlies mainly avoid humans, preferring to prey on fish and large animals. The grizzly bear is particularly aggressive when threatened, and attacks on humans have been recorded.
Grizzlies are quite large, with adult males weighing between 400-1,500 lbs (180-480 kg) and standing up to 8 ft (2.4 m) tall. Female bears are generally 1/3 smaller. Their immensely powerful hind legs allow them to stand up to get a view of their surroundings or as part of aggressive behavior. The grizzly bear is an impressive runner, able to attain speeds of 25 miles per hour (40 kph.) Their coloration varies from region to region, ranging from cinnamon red to almost completely black.
Like most brown bear species, the grizzly bear hibernates during winter months. During this period, females give birth, often to twin cubs. Cubs are very small at birth, weighing only one pound (453 g.) Cubs remain with their mothers for at least two years, and accompany her on hunts. Mother grizzlies are fiercely protective of their offspring, and will often attack anything that comes between them and their cubs.
The history between grizzlies and humans is complicated. As the American population expanded westward, the large ranges of the bears were frequently overtaken by the arrival of Despite the fact that grizzlies mostly avoid people, early settlers frequently killed the animals on sight, because of their fearsome reputation. Their pelt was also considered valuable trading material, leading to the commercial hunting of the animal as well. By the late 1870s, the population of bears had been severely reduced.
As an apex predator, grizzly bears are essential in maintaining sustainable balance in their ecosystems. By capping the population of deer and other ungulates, and by turning soil over in their pursuit of berries and shoots, the grizzly bear helps to maintain plant biodiversity. As grizzly populations declined and ungulate levels increased, available plant life shrank in the bears’ former habitats. With re-introduction programs of the late 20th century, experts have observed increased plant and avian diversity in the ranges where the bears have been released.
Grizzly bears have been known to attack humans, usually when startled or separated from their cubs. In bad food years, grizzlies have also attacked human campsites in search of anything edible. Campers in grizzly bear areas are warned to securely pack away any aromatic items before going to sleep, and preferably to tie them in a bag and suspend high off the ground. While grizzlies do not often prey on humans, they can be fiercely territorial and should not be approached under any circumstances.
Since the late 20th century, all United States national parks have forbidden the hunting of bears. Although some animals have fallen victim to accidents and occasionally are hit by trains or cars, the population levels of grizzlies have risen considerably since the protection laws were created. Despite increased numbers, the bears are not totally safe from threats of pollution and climate change, and many conservation organizations exist to help maintain the natural ranges and ensure the prosperous future of the grizzly bear.