Grizzly Bear

? Grizzly Bear Conservation status: Endangered
Two Grizzly Bears in a meadow
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Ursidae Genus: Ursus Species: U. arctos Subspecies: U. a. horribilis
Trinomial name
Ursus arctos horribilis ( Ord, 1815)

The Grizzly Bear, sometimes called the Silvertip Bear, has traditionally been treated as a subspecies, Ursus arctos horribilis, of the brown bear living in North America. However, DNA analysis has recently revealed that the subspecies of brown bears, both Eurasian and North American, are genetically quite homogeneous, and that their genetic phylogeography does not correspond to their traditional taxonomy. Therefore, the common name Grizzly Bear can be appropriately used to refer to interior North American Brown Bears, whereas the coastal bears of North America are referred to as Kodiak Bears or Kodiak Brown Bears, and those of Europe, the European Brown Bear.

Grizzly Bears reach weights of 180-680 kg (400-1500 lbs); the male is on average 1.8 times as heavy as the female, an example of sexual dimorphism. Their coloring ranges widely across geographic areas, from blond to deep brown or black. These differences, once attributed to subspeciation, are now thought to be primarily due to the different environments these bears inhabit, particularly with regard to diet and temperature.

The Grizzly has a large hump over the shoulders which is a muscle mass used to power the forelimbs in digging. The head is large and round with a concave facial profile. In spite of their massive size, these bears can run at speeds of up to 55 km/h (35 mph).

Normally a solitary, nocturnally active animal, in coastal areas the Grizzly congregates alongside streams and rivers during the salmon spawn. Every other year females (sows) produce 1-4 young (most commonly 2) which are small and weigh only about 500 g (1 pound). Sows are very protective of their offspring.

The current range of the Grizzly Bear extends from Alaska, down through much of Western Canada, and into the upper Northwestern United States including Idaho, Montana and Wyoming.

Diet

Being omnivores, grizzlies feed on a variety of plants and berries including roots or sprouts and fungi, as well as fish, insects and small mammals. The larger bears have been known to prey on large mammals such as moose, sheep and caribou. Bears with access to a protein-rich diet, such as the coastal bears which feed on salmon, can grow much larger than their herbivorous cousins.

In preparation for winter, bears will gain hundreds of kilograms of fat before going into a state of false hibernation. There is some debate amongst professionals as to whether or not Grizzly Bears technically hibernate. Much of this debate revolves around body temperature and the ability for the bears to move around during hibernation on occasion. One interesting adaptation is that Grizzly Bears have the ability to partially recycle their body wastes during this period. In some areas where food is plentiful all year round, Grizzly Bears will forgo hibernation altogether.

Legal status

The Grizzly Bear is listed as threatened in the contiguous United States, and endangered in parts of Canada. It is currently slowly repopulating areas where it was previously extirpated. On January 9, 2006, the US Fish and Wildlife service proposed to remove Yellowstone grizzlies from the list of threatened and protected species.

Some biologists have argued that the word horribilis should be removed from the bear's taxonomic name, as its negative connotations may hinder conservation efforts. This change would not be permitted by the International Code of Zoological Nomenclature.

In case of bear attack

The best way to avoid injury from a bear attack is to avoid being attacked. If you see a bear, leave it alone and leave the area. Do not disturb or approach it.

However, if the bear advances upon you, it can be difficult to evade. Bears can run much faster than humans, and they are better tree climbers as well. Some travelers in bear country carry pepper spray or large caliber firearms to repel or kill an attacking bear.

A frequent reason for a sow to attack a human is that the sow thinks the human is threatening its cubs. In this case, the sow will attack to disable the threat and then typically leave. Laying very still and feigning death has preserved the lives of people caught in such a situation. Hungry or ill bears may attack humans for other reasons and should be expected to behave differently.

Trivia

Werner Herzog's 2005 film Grizzly Man deals with the story of Timothy Treadwell, a man who lived for over 13 years with Kodiak brown bears in Alaska.