grizzly bear
| grizzly bear | ||||||||||||
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Grizzly Bear in Yellowstone National Park |
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| Ursus arctos horribilis | ||||||||||||
| Ord , 1815 |
The grizzly bear ( Ursus arctos horribilis ), more rarely Grizzly called, is one in North America living subspecies of brown bears . In earlier times one assumed numerous different subspecies on this continent, today all brown bears living there, with the exception of the Kodiak bears, are generally referred to as grizzly bears.
features
The fur color and size of these animals vary in their area of distribution. The term “grizzly” (from English for “greyish”) refers to his upper coat, the hair of which often has gray tips at the ends or changes from light to dark. Animals in the Rocky Mountains in particular have this characteristic, which is particularly pronounced on the back or shoulder area. But grizzlies can also be red-blonde, yellow-brown, dark brown or almost black in color. Occasionally they have a large white patch on the chest that can extend down to the shoulders like a collar. The color of the fur depends mainly on the habitat, especially the food and the climate. After shedding the winter coat, the new top coat is regularly darker. Shortly before the change from summer fur to winter fur, the fur has a lighter, almost faded tint. This is often the case with individuals whose basic color is brown or blonde.
The size of the grizzly bear generally decreases from north to south ( Bergmann's rule ). While the animals in the north can weigh up to 680 kilograms, in the south they are significantly lighter at 80 to 200 kilograms. Everywhere the males are significantly heavier than the females, on average 1.8 times. The head-trunk length of the grizzly bear is 1.5 to 2.5 meters, its tail measures 10 to 12 centimeters. The shoulder height is up to 1.5 meters.
The build corresponds to that of the rest of the bears, the body is stocky, the limbs are long and strong. The feet each have five non-retractable claws. Like all bears, grizzlies are sole walkers . The tail is a short stub, the head is massive and round. Like all brown bears, it has a hump on the neck that consists of a strong muscle mass. He needs these to use his front paws effectively. He hunts with his paws, catches salmon, turns stones for food and digs caves. In addition to the hump on the neck, the muzzle, which is more distinct from the head, is a characteristic that makes it distinguishable from the American black bear , which is often the same color. In black bears, the lighter tint around the nose to the snout is more pronounced than in grizzly bears.
In the wild, grizzlies can live up to 30 years of age.
distribution and habitat
The original range of the grizzly bears covers large parts of western and central North America . It comes from a Eurasian brown bear population that immigrated via the sometimes dry Bering Strait . It spread through forests and tundra across the continent as far as Mexico . How far its range extended to the east is unknown, but bone finds from the Labrador Peninsula , Kentucky and Ohio indicate that it extended further than originally assumed.
The decline in populations may already have started when the Indians honed their hunting techniques thanks to horses introduced by the Spanish . With the large-scale settlement of the country by the Europeans, there was a drastic decline in the population and the distribution area. Yellowstone National Park, founded in 1872, proved to be an important retreat . In the core area of the United States (the 48 contiguous states excluding Alaska and Hawaii) between 1,100 and 1,200 animals live in several isolated populations in the northwestern part of the country. In the Greater Yellowstone Ecosystem around Yellowstone National Park and the adjacent Grand Teton National Park live over 500 animals, in Glacier National Park and its surroundings between 400 and 500, in the US American part of the Selkirk Mountains around 40-50, in the Cabinet- Yaak area on the border between Idaho and Montana about 30-40 and in the northern Cascade Mountains around the North Cascades National Park about five animals. In Canada they have also disappeared from the central parts of the country and are now only found in British Columbia , western Alberta and the northern territories. They are still relatively common in sparsely populated Alaska . Today's total population is estimated at around 50,000 animals.
Way of life
Grizzly bears are usually solitary animals and are active both day and night. In regions where they rarely meet people, grizzlies often use subalpine, open pastures for foraging during the day and move far away from dense shrubbery and trees that can give them privacy. They overslept the particularly hot times of the day. They usually have their action highlight during the cooler times of the day and at dusk. A particularly abundant food supply, such as is found in berry-rich regions or on rivers during the salmon spawning season , sometimes leads to the gathering of many bears.
Despite its massive build, the grizzly bear can reach speeds of over 60 km / h. Except when hunting, however, it usually moves at a leisurely pace. He usually goes on all fours. To get a better overview, he can stand on his back legs and take a few steps.
Grizzlies hibernate during the cold season . Since the body temperature drops only a little and you are easy to wake up, one does not speak of a real hibernation . To prepare for this, stock up on fat in late summer and fall. Grizzlies kept in zoos are often active even in winter, albeit with a certain lethargy. The winter dormancy is mainly due to a reaction to a reduced food supply and less to the cold. Mountain slopes on which grizzlies have their winter caves usually have an incline of 25 to 45 degrees. In rare cases they are even steeper. Grizzly bears often use hills that have particularly thick blankets of snow.
food
Grizzly bears, like most bears, are omnivores . Vegetable food includes grasses, herbs, saplings, flowers, roots, tubers, nuts and mushrooms on their menu; in summer and autumn berries are an important part of their diet. In comparison to other carnivores, bears have an elongated intestine, but in comparison to ruminants, they are difficult to fully utilize plants that are poor in nutrients. They therefore prefer plants that are fully ripe and easy to digest. This food is not yet available in spring. Grizzly bears then mainly eat saplings and fresh shoots such as those of the raspberry and roots. At this time, the roots of various types of sweet clover play a major role . In many parts of their distribution area, grizzlies always stay just below the dew line at the beginning of spring in order to benefit from this fresh spring growth. However, grizzly bears only create the fat deposits that are necessary for wintering in summer and autumn when berries and fruits ripen. Canadian buffaloberries are one of the main food sources during this time.
In terms of carnal food, they eat insects and their larvae, which despite their small size play a significant role as a source of fat and protein. Especially in bad berry years, grizzly bears eat large amounts of crickets , grasshoppers , snails as well as ants and their larvae during the summer . Also cutworm can play an important role in the diet. In 1972, for example, a female bear was observed with three cubs, whose main source of food over a period of four weeks consisted of these butterflies that they peeled from under stones. Birds and their eggs as well as rodents such as squirrels , lemmings , pocket rats and voles play a greater role in the food spectrum of the grizzly bear than the American black bear, since grizzlys can dig up this prey more easily than black bears. To a greater extent than Eurasian brown bear grizzly hunting large mammals such as moose , reindeer , elk , bison , white-tailed deer and pronghorn . Where available, they sometimes kill grazing animals such as sheep , goats and cattle . When looking for food, their keen sense of smell plays a major role. They are therefore able, for example, to track down newly born deer calves that are still relatively odorless. They also have excellent hearing and can hear the bleating of a deer calf from over 500 meters.
For grizzly bears that live on the Pacific coasts of the north, salmon make up a significant part of the diet during their spawning migrations upriver. This protein-rich food is probably responsible for the fact that the animals in the north become significantly larger than their inland counterparts.
Reproduction
The females give birth to between one and four, but usually two, young about every other year. The mating season is in June and July. The embryos do not begin to develop until the hibernation in November or December. The young are born in January or February after a two-month development period. With a body length of around 30 cm and an average of 350 g, they are very small. Babies are blind and deaf in the first month after birth. After two to three years, they leave their mother.
Grizzly bears are closely related to polar bears and can beget offspring with them.
Grizzly bear and human
Even the Indians hunted and worshiped the grizzly. Its meat was eaten, its fur made into clothing and blankets, and its claws and teeth used as ornaments. The bear also plays an important role in many tribes in mythology and as a totem animal .
European immigrants saw the grizzly mostly as a competitor in food procurement and as a potential danger. This view caused the drastic decline in the population after the arrival of the white settlers. Today the grizzlies are protected in many places and their populations are stable. Thanks to the population increase to around 500 specimens in the Greater Yellowstone Ecosystem , the species in this range could be removed from the list of threatened species under the Endangered Species Act at the end of April 2007 . As early as 2009, however, a district court in Montana ordered the authorities to put the grizzly back on the list. The population remains threatened in four other areas of the United States.
In the 1970s, like the black bears , the grizzlies in Yellowstone National Park got used to the people and their food. They ate confectionery such as biscuits and ice cream, but also barbecue waste. Accidents between humans and the bears increased. After the National Park Service took a number of measures - including closed trash cans, a feed ban, and relocation of bears - the grizzly bears gradually resumed their primal, wild ways.
Endangering people
Because of its great strength, a single bite or paw blow from a grizzly bear can cause serious injury or even death to humans. However, they usually move away when they hear people approach, which is why the national park administrations in North America recommend that you move around noisily. Even so, there are isolated deaths almost every year; especially when encounters with injured animals, with females that have young animals with them, with animals that eat carcasses, or when humans have a dog with them.
See also
literature
- MA Cronin, SC Amstrup, GW Garner, ER Vyse: Interspecific and specific mitochondrial DNA variation in North American bears ( Ursus ) . Canadian Journal of Zoology, 1991, 69: 2985-2992, ISSN 0008-4301 .
- Stephen Herrero: Bears - Hunters and Hunted in America's Wilderness , Müller Rüschlikon Verlag, Cham 1992, ISBN 3-275-01030-1
- LP Waits, SL Talbot, RH Ward, GF Shields: Mitochondrial DNA phylogeography of the North American brown bear and implications for conservation . Conservation Biology, 1998, 12: 408-417, ISSN 0888-8892 .
- Bernd Brunner: A Brief History of the Bears . Claassen-Verlag, 2005, ISBN 3-546-00395-0 .
- Charlie Russel, Maureen Enns: The Bear's Soul. Our life with the grizzlies of Kamchatka . Goldmann-Verlag, 2002, ISBN 3-442-30993-X .
Individual evidence
- ^ Herrero, p. 192
- ↑ a b U.S. Fish & Wildlife Service: Successful Recovery Efforts bring Yellowstone Grizzly Bears off the Endangered List
- ^ Herrero, p. 219
- ↑ Herrero, p. 220
- ^ Herrero, p. 221
- ↑ Herrero, p. 203
- ^ Herrero, p. 210 and p. 211
- ↑ Herrero, p. 212
- ^ Herrero, p. 195 and p. 197
- ↑ National Geographic: Polar Bear-Grizzly Hybrid Discovered (accessed April 25, 2007)
- ^ [1] English, worship of the grizzly bear among North American Indian tribes
- ↑ Decision of the US District Court for the District of Montana Missoula Division (PDF; 217 kB)
