Brown bears appeared in Eurasia about 50, 000 years ago. Some of them also moved to North America, where it spread and lives about 13, 000 years. In the 19th century, scientists classified 86 individual species of grizzly bears that live on the North American continent. However, by 1928 the scientific community narrowed their number to seven, and by 1953 only one species was isolated.
In 1963, it became clear that grizzlies are not a separate species, but a subspecies of a brown bear, and this has been confirmed by modern genetic testing. According to external differences and habitat, several of its subspecies were distinguished, however, the classification was revised according to genetic lines, and today there are two morphological forms: continental and coastal grizzly bear. In scientific sources, it is customary to call it the North American brown bear.
External features
Like other subspecies of brown bear, the brown color of the grizzly coat can vary from light beige to almost black. In the latter, the coat color is distinguished by a darker shade on the legs and light on the back. In representatives of the Rocky Mountains, the tips of the outer coat are white, which creates a grayish color for the animal.
The external signs of a grizzly bear and a brown bear have a number of characteristic features. As animals grow older, a clearly defined hump appears in the withers area, which is a good way to distinguish grizzlies from a black bear that lives in the same places. Small rounded ears and croup, located below the shoulder line, is an anatomical structure, also distinctive for a brown bear and not inherent in a black one. The two claws are also distinguished by the length of the front claws, which is 2.5-5 cm for the black representative, and about 5-10 cm for the grizzly, which corresponds to the size of the claws of other subspecies of the brown bear.
Size and weight
The main difference between a grizzly bear and a brown bear of Eurasia is in size and weight. The coastal representatives of the species are larger than those that live in the depths of the continent, and, like all of the bear family, females are smaller than males. Most adult female bears reach 130-180 kg, and males usually weigh 180-360 kg, newborn cubs do not exceed 500 grams. The average weight of coastal grizzlies is 408 kg for males and 227 kg for females. The corresponding weight of continental bears is 272 and 227 kilograms.
Average subspecies sizes:
- length -198 cm;
- height at withers -102 cm;
- hind legs 28 cm.
However, individuals were significantly greater than normal sizes and weights. There is a well-known example of the largest grizzly bear - a coastal male weighing 680 kg and 1.5 meters high at the withers. Standing on its hind legs, this bear reached almost three meters high. Grizzlies are sometimes superior in size and weight, but they are erroneous because they correspond to the parameters of Kodiak, another larger subspecies of brown bear.
Range and abundance
In North America, grizzlies once inhabited from Alaska to Mexico. Now, given Canada and the United States, their range has been halved, with 55, 000 wild bears. The places where the grizzly bear lives are limited to Alaska, the vast territory of western Canada, the northwestern part of the United States, including Idaho, Washington, Montana and Wyoming, to the south of Yellowstone and Great National Parks.
Most of the population lives in Alaska. The predominant number of bears is registered in Canada: about 25, 000 individuals inhabit British Columbia, Alberta, Yukon, the northwestern territories of Nunavut and the northern part of Manitoba. According to estimates by the University of Alberta, 16, 014 grizzly bears inhabited British Columbia in 2008, and in 2012 their number was 15, 075. The current population count is based on DNA samples, the recapture method, and an advanced multiple regression model.
About 1, 500 grizzlies remain in the United States. Of these, close to 800 individuals live in Montana, 600 bears live in the Yellowstone-Teton area of Wyoming, 70-100 are observed in northern and eastern Idaho.
Population reduction
The initial range of the grizzly bear in the United States included the Great Plains and the predominant part of the southwestern states, but the population was exterminated in most of these areas. Before California joined the United States, the California Grizzly, which was a symbol of the Republic, was marked on its national flag. The last bear in all of California was killed in the foothills of the Sierra in August 1922. In Colorado, the last representative was spotted in 1979. And on the vast territory of the Cascade Mountains of Washington State, there are now less than 20 grizzly bears.
The reduction in the population was significantly affected by hunting and the development of human activities, occupying the former habitats of the grizzly. Other factors:
- competition with other, more adapted predators;
- attack on grizzly cubs;
- reproductive, biological and behavioral properties of brown bears.
Lifestyle & Reproduction
Apart from females with cubs, all brown bears are solitary animals. An exceptional feature of large grizzly bears in the coastal areas of North America is to gather in groups near streams, lakes and rivers during salmon spawning. Every adult male grizzly man cares for personal possessions of up to 4, 000 km 2. Such a large territory and small population significantly complicate the search for the smell of the female. The grizzly is in a state of hibernation for 5-7 months a year.
The grizzly bear has one of the lowest reproductive rates among all terrestrial mammals in North America. Animals reach puberty only at the age of not less than five years. After the summer mating season, the female can delay the implantation of the embryo until hibernation, which explains the large difference in gestational age - from 180 to 250 days. If the bear did not receive proper nutrition, the necessary calories and substances, then the miscarriage occurs.
The litter numbers from one to four cubs, but more often twins or triplets are born, which the female produces during hibernation. Dipper takes care of the cubs for two years, during which she does not mate. Often, cubs do not live up to this age, becoming victims of predators. During the time spent with the mother, the calves gain weight up to 45 kg. When two-year-old bears leave their mother, the she-bear cannot produce the next litter for three or more years, depending on environmental conditions.
Life span
A grizzly bear belongs to long-living animals. Males, on average, live to be 22 years old, and the age of the female bears often exceeds 26 years. Females live longer than males because of safer behavior and the fact that they do not participate in mating season fights of males. The oldest continental wild grizzly is recorded in Alaska; he lived for 34 years. The oldest coastal bear lived to be 39 years old. Not less than 50% of grizzlies living in captivity survive to 44 years. But most bears die in the first years of life from predators or hunting.
