Grizzly Bear, Ursus arctos horribilis
The grizzly bear (Ursus arctos horribilis), also known as the grizzly, the North American brown bear, or the silvertip bear, is one of many subspecies of the brown bear. It is typically found in upland areas of western North America. Its range once extended from Canada to Mexico and even into the western shores of the Hudson Bay in the east. Its range has been reduced to many areas of Canada, Alaska, and northwestern areas of the United States including Washington, Wyoming, Idaho, and Montana. Its range does include Yellowstone National Park and Teton National Park. This species derives its common name from the grey coloring within its fur, which is known as grizzled. George Ord, the naturalist who gave the bear it’s scientific name, mistook the name “grizzly” as “grisly,” using the Latin term for “awesome” or “horrible,” horribilis.
The grizzly bear can vary in size depending upon the sex. Males can reach an average weight between 400 and 790 pounds, while females reach an average weight between 290 and 440 pounds. Both males and females can reach a body length of around 6.5 feet and a height of 3.35 feet. In certain areas of its range, female grizzlies have been known to weigh as little as 220 pounds, and one male was found weighing 1,500 pounds. The coloring of this species is typically brown with grey hairs throughout the fur, but it can vary from blonde to nearly black in color. The grizzly bear can be distinguished from black bears because of a hump that appears on its shoulders, which black bears lack.
The grizzly bear is typically solitary, excluding mothers raising cubs. In coastal areas, this species will gather near rivers, streams, ponds, and lakes when salmon spawn their young. The breeding season for this species occurs during the summer, and after breeding, females will delay pregnancy until they can hibernate. If a female has not gained enough fat during the year before she enters hibernation, she can miscarry her cubs due to that lack of nutrients. An average litter contains two cubs, which the mother will raise for up to two years. During this time, the mother will not mate, and when the cubs or weaned or if they happen to be killed before they can be weaned, the mother may not mate for three or more years. Although males hold a large territory of up to 1,500 square miles, finding a female to breed with can be difficult because the species occurs in low population densities.
The diet of the grizzly bear is similar to that of other bears, consisting of both plant materials and animal matter. This species is skilled at hunting large prey and will consume animals like sheep, deer, caribou, elk, moose, and occasionally black bears. It will also eat many types of fish including salmon, bass, and trout, and bears located in areas where these fish are present in large numbers often grow larger than bears in other areas. Although this species is able to find its own food, it will often scavenge for food left by other creatures or carrion.
Grizzly bears found in Alaska and Canada are typically larger than those that can be found in the Rocky Mountains in America. The bears in this area are thought to consume more animal material, which gives them better nutrition. The typical diet of these bears in Yellowstone National Park consists of tubers, grasses, whitebark pine nuts, army cutworm moths or miller moth, and carrion. Although this species does consume salmon when available, their normal diet does not provide as many nutrients as the diet of bears found in Alaska and British Columbia.
The diet of the grizzly bear varies depending upon its location and seasonal changes. It is thought that plant materials can make up eighty to ninety percent of this bear’s diet in any area of its range, with important types being berries. These include blue berries, cranberries, salmon berries, black berries, huckleberries, and buffalo berries. Many types of insects are consumed when available, like bees, ladybugs, and ants. In Yellowstone National Park, these bears can obtain half of their yearly intake of nutrients from miller moths, which occur in great numbers during the summer. The grizzly bear will gather in groups when food is abundant, and can be seen feeding on legumes in areas where avalanches have recently occurred.
It is vital that the grizzly bear gain enough weight during the spring, summer, and fall seasons so that they can live through hibernation during the winter months. This species can gain up to 400 pounds before hibernation occurs, but will not enter hibernation until the first considerable snow storm. It will choose dens on north facing slopes at elevations over 5,900 feet. Experts do not agree that the grizzly bear hibernates in the true sense of the word, because the bears are able to move around in their dens and will occasionally recycle their waste. If food is abundant in some areas, the grizzly will forego hibernating through the winter.
The grizzly bear plays a key role in the ecological systems of its range. It is an important seed disperser, leaving seeds behind in its feces after consuming fleshy plants, and some studies support that germination is increased in this process. Because the bears dig up tubers and roots, they stir silt into the air around them. This is thought to increase the abundance of species in alpine ecosystems. This process also increases the level of nitrogen, and can be accomplished when the bears bring salmon from the water into the trees. The grizzly bear plays a large role in controlling prey species populations, which helps prevent overgrazing. One study conducted in Wyoming in the Grand Teton National Park showed that once the bears, and wolves, were removed from forested areas, herbivorous animals increased in number, thereby decreasing the number of migratory birds within the park.
The grizzly bear shares its range with other large predators, including wolves and black bears. In Yellowstone National Park, the reintroduction of gray wolves has caused the bears to attain their old, violent relationship with the predators. Studies have shown that most encounters occur when one species is trying to protect food or young. It is common to see a bear and a pack of wolves competing for one carcass. One wolf may distract the bear from the kill while another eats, and sometimes the bear will end up chasing all of the wolves away.
Violence between these two species usually consists of a wolf nipping at the bear’s legs, after which the bear will sit down and use its teeth and forepaws in defense. These encounters rarely end in serious injury or death, because each has an advantage over its opponent, with the bear being larger than the wolves, and the wolves having the support of an entire pack.
Although black bears tend to avoid the territories of grizzly bears, grizzly bears will enter into a black bear’s territory to consume food favored by both species. These include plant materials like acorns, pine nuts, berries and mushrooms. If a black bear spots a grizzly near, it will either run away or climb into a tree to avoid confrontation. There is not much competition between the bears for animal material due to the black bear’s preference for plants. If an encounter occurs, it is most often the grizzly bear that instigates and a black bear will only fight a grizzly if it is smaller, like a yearling, or if it has no other choice.
In coastal regions, like the islands off Alaska or British Columbia, the ranges of the grizzly bear and black bear are completely separate. This is thought to have occurred because there is not much competition between the species, although they do share common food resources. The habitats in these areas can support only one species of bear, and the grizzly bear is typically the species that outcompetes the black bear. In forested areas, the two species prefer different habitat factors such as elevation and vegetation density, and this helps to keep the species separated. Smaller predators share the range of the grizzly bear, but these do not typically pose a threat to the bear. Cougars will choose to avoid bears if possible, but if it must defend its kill, it will use its reflexes to avoid being injured by the bear. When this occurs, one predator must eventually give up the kill. Other predators, like foxes, wolverines, and coyotes, do not pose a major threat to the bear’s livelihood, although they share a preference for small prey like ground squirrels and rabbits. Fox and coyotes may wait for the bear to finish its meal before moving in to consume any leftovers, but the wolverine is known to harass the bear while it eats, causing the bear to leave a larger amount of meat behind.
Some experts assert that the grizzly bear is more aggressive than black bears when defending cubs or themselves. It is also thought that this enhanced aggression may occur because the grizzly cannot climb trees to escape danger. Seventy percent of attacks occur when a mother bear feels her cubs are in danger. In most cases, grizzly bears will not attack humans do not consider them as prey. If a mother and her cub happen to find a source of food near a human settlement, violence and property damage may occur.
Aggression caused by human interference is common, especially when human actions coincide with the actions of grizzlies during seasonal changes. When salmon begin to spawn, the bears move closer to the river to eat fish. During this time, many anglers use the same rivers as bears to catch the fish, increasing the danger of attack.
Because humans often move into the grizzly bear’s territory, some members of the species have become accustomed to human actions. This creates what are known as problem bears. Despite deterrents, such as rubber bullets or foul-tasting chemicals, the bears continue to associate humans with food. Problem bears are often relocated, but some are killed. In British Columbia, the government can kill up to fifty bears per year and will spend up to one million dollars in attempts to relocate or eradicate problem bears. When camping, it is suggested that people hang food from trees at heights that bears cannot reach, although it is common for bears to find other ways of obtaining hanging food.
The grizzly bear is threatened by trophy hunting, which causes an imbalance in the numbers of male and female bears. Hunters typically kill older males, leaving their territory open to foreign males. This creates the threat of infanticide to young cubs already in the area. In British Columbia, hunting of this species is allowed as a means of wildlife management. In 2012, approximately 1,602 hunting licenses were given out by lottery by the Ministry of Forests/Lands/Natural Resource Operations.
The population numbers of the grizzly bear have decreased in the past few decades, creating a need for effective conservation efforts. There are around 25,000 bears in the species’ entire Canadian range today. When European settlers came to Canada, there were approximately 25,000 bears in British Columbia alone, but now there are around 16, 014 bears in that area. In North America, the population number of this species is estimated to be around 55,000 individuals. Grizzly bears in Canada and the United States inhabit around half of their initial range. Population estimates are obtained in a number of ways, including using hair samples and DNA studies in British Columbia. In other areas, a number of different methods can be used, but this variety makes it difficult to know which methods were used in which areas. It is thought that these bears could repopulate their original range, but this will take time due to the level of habitat destruction in areas of its range, as well as the re-introduction of competing species and the slow reproductive rate of the grizzly bear.
The grizzly bear is protected in some areas of its range, including areas of North America and Canada, Mexico, and European countries. In British Columbia, the establishment of protected areas like Khutzeymateen Grizzly Bear Sanctuary, which holds 109,000 acres of vital coastal habitat, is important in saving this species. This location, among other possible areas, was chosen because of its habitat features as well as its proximity to other viable habitats. In Khutzeymateen Grizzly Bear Sanctuary, the grizzly bear is protected by a no hunting policy, as well as a limited amount of visitors. Another area in Canada, located in Vancouver, is dedicated to educating the public on the importance of saving the grizzly bear. In 2001, two orphaned cubs were placed in the sanctuary, which holds five acres.
Roads and human settlements like cities fragment many viable areas that could be converted into protected areas for the grizzly bear. Bears in these areas, such as Bluff Park, suffer from a decline in genetic diversity due to their fragmented habitat, so conservations have begun to include plans for migration corridors. These corridors include overpasses or tunnels, which bypass busy roadways and allow the bears to move through their habitat with lessened chances of death. By using GPS collars to track the bears, scientists have found that the corridors are not often used, so genetic diversity is still an increasing problem.
In the United States, the grizzly bear is listed as a threatened species by the U.S. Fish and Wildlife Service, excluding the bears found in Alaska. In Canada, this bear is listed as endangered and it appears in the COSEWIC registry as species of Special Concern. In 2002, the grizzly bears located in the Saskatchewan, Manitoba, and Alberta regions were listed as being wiped out by the Canadian Species at Risk Act.
Conservation efforts in the U.S. typically occur in six areas. These are Selway-Bitterroot, Yellowstone national Park, the Northern Continental Divide, Selkirk, the North Cascades, and Cabinet-Yaak. The largest population in these areas occurs in the Northern Continental Divide, where 750 bears reside, while the small population is believed to number between 10 and 20 bears in the Northern Cascades, although there are no recorded individuals in Selway-Bitterroots. Within these areas, and bordering areas in Canada, it is difficult to record the exact population numbers because the bears move between territories.
All of the national parks in the United States offer full protection to the grizzly bears from hunters, but even with these regulations in place, grizzlies are still in danger of accidents associated with manmade objects. In Banff National Park and Glacier National Park, grizzly bears are often found killed by trains, because trains carry grain in these areas that is not well protected from the bears. They can also be killed in motor vehicle accidents on roads that go through the parks. Most bears located in the Central Rocky Mountains have died within a thousand feet of roads.
In 2006, the U.S. Fish and Wildlife Service suggested that the grizzly bears in Yellowstone National Park should be removed from the list of threatened and protected species, and this was accomplished in March of 2007. In doing so, the grizzly bear lost all of the protection that the Endangered Species Act offers, and a many groups, including the NRDC, urging the government to re-list the bear as an endangered species, brought the federal government to court. The grizzly bear was re-listed as an endangered species in 2009, due to a decrease in their major local food source, the whitebark pine tree.
In Alberta Canada, studies conducted on the fur of the grizzly bear resulted in the findings that the bear might be increasing in population numbers. In 2002, it was recommended by the Endangered Species Conservation Committee that the Alberta grizzly bears be listed as threatened, despite the increase that was found in 2000. In 2008, a report issued by the Provincial government showed that the Alberta grizzly bears were actually declining, and in 2010, the population containing 700 bears was listed as threatened. One group, called Environment Canada considers the grizzly bear to be a species of special concern, because it is fragile to human environments and actions. In British Columbia and Alberta, the grizzly is listed as an “at risk” species. Despite its threatened or endangered status in local areas, the grizzly bear appears on the IUCN Red List as a species of “Least Concern.”
Image Caption: Grizzly Bears at Brooks Falls Katmai National Park. Credit: Brocken Inaglory/Wikipedia (CC BY-SA 3.0)