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Post by brobear on Mar 18, 2017 6:58:07 GMT -5
I will begin by discussing the name "grizzly". en.wikipedia.org/wiki/Grizzly_bear Meaning of "grizzly" Meriwether Lewis and William Clark named it to be grisley or "grizzly", which could have meant "grizzled" (that is, golden and grey tips of the hair) or "fear-inspiring".Nonetheless, after careful study, naturalist George Ord formally classified it in 1815 – not for its hair, but for its character – as Ursus horribilis ("terrifying bear"). So, the name "grizzly" was originally used only for all of North America's brown bears with the exception of those found on Kodiak Island. However, as time goes forward, more and more often the name "grizzly" is generally given to any and all brown bears, all of which belong to a single species, Ursus arctos. Today, at least with the people of North America, there remain but a few die-hard naturalists who refuse to call any but Ursus arctos horribilis by the name "grizzly." I prefer grizzly to brown bears mainly for two reasons. Not all black bears are black and not all brown bears are brown. Secondly, since each species of big cat has his own unique name, I feel that bears deserve no less. We call the "maned cat" a lion and the "striped cat" a tiger. I will therefore call our brown bear the grizzly.
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Post by brobear on Mar 18, 2017 7:00:13 GMT -5
westernwildlife.org/grizzly-bear-outreach-project/biology-behavior/ Grizzly Bear Behavior - Although sometimes portrayed in the media as voracious predators, grizzly bears are normally reclusive creatures. Grizzly bears are intelligent, curious, and have excellent memory, particularly regarding where food sources are located.They have good eyesight and excellent senses of hearing and smell. Grizzly bears are active during the day and night, but will often alter their habits to avoid humans in areas of high human use.In the heat of the day, grizzly bears will rest in day beds in dense vegetation, including willows, alders, dense forest, and tall grass. Most grizzly bears spend their time alone except when breeding or raising cubs. Grizzly Bear Reproduction and Maturation Grizzly bears often live to be around 20 to 25 years of age Mating occurs from May through July with a peak in mid-June. Female grizzlies begin bearing young at 3 to 8 years of age, and litter size varies from one to four cubs, with an average litter of two. Grizzly bears have a promiscuous mating system: cubs from the same litter can have different fathers. Cubs are born in the den in late January or early February and remain with the female for 2 to 3 years before the mother mates again and produces another litter. Grizzly bears have one of the slowest reproductive rates among terrestrial mammals, due to their late age of first reproduction, small average litter size, and the long interval between litters: it may take a single female 10 years to replace herself in a population.Female grizzly bear stop breeding in their mid-to late 20s. The typical female may give birth to a maximum of 10 cubs over her lifetime, half of which usually die within a year. Surviving cubs usually remain with the mother for 2 1/2 to 3 1/2 years, during which time the mother will not mate. Grizzly Bear Diet Grizzly bears are opportunistic omnivores. In Washington and Idaho, a typical grizzly bear diet is less than 10% fish or meat, and much of the meat is carrion from winter-killed deer and elk. In areas where animal matter is less available, grasses, roots, bulbs, tubers, and fungi are important parts of the grizzly diet.Grizzly bears visit wetlands in the spring for succulent plants that are easy to digest and are high in nutrients. Summer foods include thistle, cow parsnip, mushrooms, roots, spawning fish, wild berries, and insects (including clusters of adult moths at high-elevations). Fall foods include berries very important, plants, and ants.During years when there are shortages of natural food sources, conflicts between humans and grizzly bears are more frequent, resulting in higher numbers of human- caused grizzly bear mortalities due to defense of life or property, and management removals of nuisance bears. Grizzly Bear Habitat and Territory Grizzly bears are most often found on upper elevation slopes, in avalanche chutes, and in lower elevation wetlands. Female grizzly bears need about 50 to 300 square miles of habitat, and males require 200 to 500 square miles.Grizzly bears usually have overlapping ranges with several bears sharing an area.Although adult grizzly bears are normally solitary, home ranges of adults frequently overlap, with young grizzlies establishing home ranges within or overlapping their mother’s. This makes dispersal across landscapes a slow process. Grizzly Bear Denning and HibernationFor 3 to 6 months during winter, grizzly bears enter dens and hibernate during periods of low food availability, deep snow, and low air temperature. Grizzly bears in the lower 48 states spend up to 4 to 6 months in dens beginning in October or November.During hibernation, grizzly bears do not eat, drink, urinate, or defecate. Denning grizzly bears exhibit a marked decline in heart and respiration rate, but only a slight drop in body temperature. Due to their relatively constant body temperature in the den, denning grizzly bears can be easily aroused and have been known to exit dens when disturbed. Both males and females have a tendency to use the same general area year after year but the same exact den site is rarely used twice by an individual.In preparation for hibernation denning, grizzly bears consume excess amounts of food and the bears may gain more than 3 ½ pounds a day, deposited as fat. The excess fat also serves as energy to the bear upon emergence from the den, when food is still sparse.Grizzly Bear CommunicationA bear’s body language can help reveal its mood. Bears may stand on their hind legs or approach to get a better view, but these actions are not necessarily signs of aggression. In general, bears show agitation by swaying their heads, huffing, popping their jaws, blowing and snorting, or clacking their teeth. Lowered head and laid-back ears also indicate aggression. Ecological Role of Grizzly Bears Grizzly bears play an important role in forest ecosystems as seed dispersers and nutrient providers. Berry seeds pass through the bear unbroken and are able to geminate. Not only that, but they come with their own pile of fresh manure as fertilizer.While foraging for tree roots, plant bulbs, or ground squirrels, bears stir up the soil, increasing species richness and nitrogen availability in alpine ecosystems. Grizzlies increase the amount of available nitrogen through soil disturbance and through salmon carcass dispersal.Grizzlies also directly regulate prey populations and help prevent ungulate overgrazing. Studies show that the removal of wolves and grizzly bears in Grand Teton National Park caused populations of their herbivorous prey to increase, which decreased the density of plants in the area. The decrease of plant density led to a decrease in the population sizes of migratory birds. Grizzly bears, like all carnivores, are keystone predators, having a major influence on their ecosystems.
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Post by brobear on Mar 20, 2017 6:52:47 GMT -5
Grizzlies of the Northern Cascades within the Cabinet Mountains. www.fws.gov/mountain-prairie/species/mammals/grizzly/CabYaak2014ReportFinallowres.pdf INTRODUCTION Grizzly bear (Ursus arctos) populations south of Canada are currently listed as Threatened under the terms of the 1973 Endangered Species Act (16 U.S.C. 1531-1543). In 1993 a revised Recovery Plan for grizzly bears was adopted to aid the recovery of this species within ecosystems that they or their habitat occupy (USFWS 1993). Seven areas were identified in the Recovery Plan, one of which was the Cabinet-Yaak Grizzly Bear Recovery Zone (CYGBRZ) of extreme northwestern Montana and northeast Idaho (Fig. 1). This area lies directly south of Canada and encompasses approximately 6800 km2 . The Kootenai River bisects the CYGBRZ, with grizzly bear habitat within the Cabinet Mountains to the south and the Yaak River drainage to the north (Fig. 2). The degree of grizzly bear movement between the two portions is unknown but thought to be minimal.
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Post by brobear on Mar 20, 2017 6:53:39 GMT -5
cordilleramontana.worldnow.com/story/32566673/grizzly-bear-relocated-to-the-cabinet-mountains Grizzly bear relocated to the Cabinet Mountains Posted: Jul 28, 2016 3:33 PM CDT Updated: Jul 28, 2016 3:37 PM CDT By MTN News KALISPELL - Efforts to replenish the grizzly bear population in the Cabinet Mountains are going well for wildlife specialists. A 3-year-old grizzly bear that was captured on the South Fork of the Flathead River was recently released back into the wild. Montana Fish, Wildlife and Parks officials say the male bear was released above Spar Lake in the Kootenai National Forest on Monday. The relocation is part of an on-going effort to boost the grizzly population in the Cabinet Mountains. The bear that was released was fitted with a GPS collar so its location can be tracked and movements monitored. "This particular bear met all the criteria," said FWP spokesman John Fraley. "It was a young male, healthy and no conflict with humans in its history, so it was a good bear to put into the Cabinet-Yaak." "We got a ways to go anyway, we're only at about 50 bears," he added. "So this being a male, we hope that it will get into the population of bears in the Cabinet-Yaak and procreate and add to that system so the ultimate goal is to boost and recover the population." Fraley says they are trying get about 100 bears in the Cabinet-Yaak area, with the goal of eventually de-listing of grizzly bears so that they are back into state management.
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Post by brobear on Mar 20, 2017 6:55:45 GMT -5
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Post by brobear on Mar 20, 2017 12:53:06 GMT -5
The Grizzly, Our Greatest Wild Animal by Enos Abijah Mills A grizzly is strongly attached to his home territory and spends most of his time in it. Occasionally, and in exceptional cases regularly, he wanders far away. A scarcity of food may cause him to leave home temporarily; or excessive food elsewhere may attract him. The abundance of food at any place in a bear's territory gives other grizzlies public rights. A berry-patch or a stream which has a supply equal to the needs of many bears, a beaver pond, or a lake, may become a public feeding-place. A flood, a storm, a snow-slide, or other agency may take the lives of a number of animals - cause a congestion of food in any territory. That there sometimes is fighting in these public places, and that one bear sometimes tries to hog a larger food-supply than he can use does not change the custom of the species. Incidentally, this violation of general or public rights but reminds us how human-like are bears in their habits, good and bad.
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Post by brobear on Mar 20, 2017 12:53:41 GMT -5
The Grizzly, Our Greatest Wild Animal by Enos Abijah Mills There are a number of regions in Alaska where a bear lives in his own chosen locality but regularly goes to a public feeding-ground. Much of the food is along the seashore and on the lower courses of streams. There is also a food-belt above the timber-line, where mice abound and where there is grass upon which bears feed. The seasonal nature of part of the food may thus encourage or compel bears of one locality to travel a long distance to secure the only food obtainable. If there be straggling grizzlies who wander about like gypsies, they are the rare exception: the nearest to them were the few "buffalo grizzlies," those that in old days followed the migrating buffalo herds.
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Post by brobear on Mar 23, 2017 18:44:57 GMT -5
www.nwf.org/Wildlife/Wildlife-Library/Mammals/Grizzly-Bear.aspx Is it a brown bear or a grizzly bear? Actually it's either or both, because these are just common names that have no scientific basis. Many people in North America use the common name “grizzly bear” to refer to smaller and lighter-colored bear that occurs in interior areas where there are not a lot of salmon to eat and the term “brown bear” to refer to the larger and typically darker-colored bear in coastal areas where there are salmon. This species also occurs in Russia, Europe, Scandinavia and Asia where everyone refers to them as “brown bears”. In North American there is one subspecies that occurs in the Kodiak Island area but all of the remaining bears are the same subspecies, regardless of where they occur from Alaska to Yellowstone. There are many other subspecies in the world and, until they were killed off in the 19th and 20th centuries, there may have been more subspecies in North American as well. Here, we will refer to them all as “grizzly” bears. Grizzlies were excessively overhunted by humans, and now there are less than 1,500 grizzlies left in the United States south of Canada; there are also about 31,000 in Alaska. National Wildlife Federation is fighting for grizzly bears to make sure they have room to roam and can safely coexist with humans. Grizzly Bear Description Grizzly bears are large and range in color from very light tan (almost white) to dark brown. They have a dished face, short, rounded ears and a large shoulder hump The hump is where a mass of muscles attach to the bear’s backbone and give the bear additional strength for digging. They have very long claws on their front feet that also give them extra ability to dig after food and to dig their dens. Grizzly bears received their name because their brown fur can be tipped with white. This gives them a “grizzled” look, especially when blacklit by the sun. Bear grizzly Size: Grizzly bears weigh upwards of 700 pounds. The males are heavier than the females and can weigh up to 1,700 pounds. A large female will weigh up to 800 pounds. Diet: Grizzly bears are omnivores. The most commonly eaten plants are the fleshy roots of some plants, fruits, berries, grasses, and forbs. If grizzly bears are on the hunt, their prey can include fish (especially salmon), rodents like ground squirrels, carrion and hoofed animals like moose, elk, caribou, and deer. They are especially good at catching the young of these hoofed wildlife species. Grizzly bears can also target domestic animals like cattle and sheep and cause economically important losses for some ranchers. NWF has a program on National Forest lands surrounding Yellowstone Park to prevent attacks on domestic livestock by purchasing the grazing allotments from ranchers. Typical Lifespan: Grizzly bears can live to be 30 years in the wild, but most die before age 25. Habitat: Grizzly bears can be found in woodlands, forests, alpine meadows and prairies. In many habitats they prefer riparian areas along rivers and streams. Range: Grizzly bears once roamed throughout the entire western U.S. south into Mexico including the Great Plains and along rivers in desert habitats. Control actions and habitat loss extirpated them from 98 percent of their original habitat in the U.S. including the Great Plains and all habitats south of Yellowstone National Park and Teton National Parks in Wyoming including California, Idaho and Washington. Populations persisted in the Northern Rocky Mountains including Yellowstone and Glacier National Parks and in northwestern Montana and extreme northern Idaho next to Canada. A large population of grizzly bears lives inland in Alaska and northern Canada. The southern populations in Canada’s British Columbia and Alberta are greatly reduced. Thanks to conservation efforts since about 1975, grizzly bears are recovering well in Yellowstone and elsewhere in the northern Rockies and are even beginning to recolonize prairie habitats along the Rocky Mountain Front in Montana. Communication: Grizzly bears use sounds, movement and smells to communicate. They growl, moan or grunt, especially when females are communicating with their young or during mating season when male bears can fight each other fiercely for the opportunity to mate with receptive females. Grizzly bears also rub their bodies on trees to scratch and to let other bears know they are there. Life History and Reproduction: Winter can be very tough for many species of wildlife, because the season brings harsh weather and little food. Grizzly bears hibernate in warm dens during the winter to minimize energy expenditure at a time when natural foods are not available and to permit their tiny young to be born in a warm and secure environment. Throughout the summer and autumn, grizzlies build up fat reserves by consuming as much food as they can find. In late fall or winter, grizzly bears find a hillside and dig a hole to serve as their winter den. When inside the den, grizzly bears slow down their heart rate, reduce their temperature and metabolic activity and live off stored fat reserves. Pregnant females give birth in the dens and nurse their cubs until they are large enough to venture outside in the spring as snow melts and new food become available. Depending on the length of the winter season grizzly bears can stay in their dens for up to 7 months. They don’t even go to the bathroom during this time! Grizzly bear hibernation is not as deep a sleep as some other hibernators like bats or ground squirrels as they will quickly wake up when disturbed. Females with newborn cubs are the last to leave their dens in the spring. Females with older cubs emerge earlier and solitary females and males are the first to exit dens in the spring. Pregnant females are the first to enter dens in the fall followed by females with cubs; solitary males enter dens the latest. Grizzly bears begin to look for mates in the spring and early summer. Females can mate with more than one male during her breeding season. When a female grizzly becomes pregnant, the development of the embryo temporarily stops for several months, a process called “delayed implantation”. Delayed implantation is characteristic of all bear species and some other families of carnivores, including weasels and seals. If a female bear is unable to gain enough weight during the summer and fall, her body will tell her to not proceed with the pregnancy and the embryo will reabsorb. This gives her a head start on gaining enough weight to have a successful pregnancy the following year. When female grizzlies enter hibernation, the embryo implants in her uterus and begins gestation. In January or February, female grizzly bears give birth to 1-4 cubs (usually 2). The female will care for her young inside the den until spring when they finally step out into the world. The mother cares for her young for at least 2 more years, feeding and protecting them. When the cubs are 2.5 years old, separation from their mother typically occurs. In areas with little food, the cubs may stay with their mother longer. Typically separation happens when the female enters breeding condition and attracts males which can be a threat to the cubs. At around 5 years of age, grizzly bears reach sexual maturity. Grizzly bears are mainly solitary and territorial, except for mothers and her cubs or when a plentiful food source is discovered. Grizzlies are known to congregate at rivers with many fish and at improperly fenced garbage dumps. Grizzlies can run pretty fast, reaching speeds as fast as 35 mph for very short sprints. They are good swimmers too. Cubs can climb trees to evade danger, but they lose this ability as their front claws grow longer.
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Post by brobear on Mar 24, 2017 2:36:56 GMT -5
wwf.panda.org/about_our_earth/species/profiles/mammals/brown_bear2/brownbear_population_distribution/ Brown Bear - Population and Distribution, A truly international species. Approximately 100,000 brown bears are estimated to live in Eurasia, and about 70,000 of those are found in the former Soviet Union. 8,000 brown bears are thought to remain in western Europe and the Carpathians (Slovakia, Poland, Ukraine, Romania), and they are also thought to be found in Palestine, eastern Siberia and the Himalayan region, possibly the Atlas Mountains of northwest Africa, and Hokkaido (Japan). The species is still fairly common in the mountainous regions of western Canada and Alaska, where its population may reach 30,000 individuals. In other parts of the United States, fewer than 1,000 grizzly bears remain.Historical Distribution of The brown bear was once distributed in northern and central Europe, Asia, the Atlas mountains of Morocco and Algeria (northern Africa), and western North America as far south as Mexico. Prior to the arrival of European settlers, it was found on the Great Plains of North America. The populations of the Sierra Nevada and southern Rockies have been extirpated, while those of Northern Mexico were lost in the 1960s. Grizzly numbers were estimated at 100,000 in the United States in the early 1900s.
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Post by brobear on Mar 24, 2017 2:37:46 GMT -5
tolweb.org/treehouses/?treehouse_id=4728 Introduction For years the grizzly bear, Ursus arctos horribilis, has been a majestic and powerful symbol of the wilderness. It is no wonder, as these massive bears are among the largest land carnivores in the world. Grizzlies are the most widespread brown bears of North America, and since the 1970’s these bears have been under intense study following a massive population crash in the 19th and 20th centuries. This treehouse will provide information on the past and present life of grizzlies, as well as insight into their unpredictable future.
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Post by brobear on Mar 24, 2017 2:38:34 GMT -5
Distribution
Grizzly bears typically live in mountain ranges where rich forests and plenty of streams are found. They will also make use of scattered meadows and grasslands within the mountains, providing a diverse environment for the grizzly to live in (US Fish and Wildlife Service, 2000).
Grizzly bears presently occupy a range that spans from the pacific coast of Alaska to Hudson’s Bay in the North, as well as most of British Columbia and some of Alberta in Canada. It is estimated that there are more than 30,000 grizzly bears in Alaska as well as 25,000 or more in Western Canada (US Fish and Wildlife, 2000). There are also approximately 1,200–1,400 grizzly bears residing in the lower 48 states of the USA (Servheen, 2008). Although most are found in the Yellowstone area and the Northern Continental Divide Ecosystem, small populations live in the North Cascades region, the Selkirk Mountains and the Cabinet Yaak area. There is a recovery zone for grizzly bears in the Bitteroot Mountains of the Northern US, but no grizzly bears live there yet.
Historically, grizzly bears could be found in much of North America, with populations spanning from the Arctic Ocean as far south as Mexico, and as far east as the Mississippi River (Ministry of Environment, 1996). Approximately 50,000 grizzly bears lived in the lower US and Mexico in the early 1800’s. Habitat destruction by humans and hunting have lead to their drastic decrease in population (US Fish and Wildlife, 2000).
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Post by brobear on Mar 24, 2017 3:01:54 GMT -5
www.nps.gov/yell/learn/nature/gbearinfo.htm Grizzly ( Ursus arctos horribilis ). Grizzly Bear Ecology - Population The estimated Greater Yellowstone Ecosystem grizzly bear population increased from 136 in 1975 to an estimated 717 in 2015, and the bears have gradually expanded their occupied habitat by more than 50%. As monitored by the Interagency Grizzly Bear Study Team, the criteria used to determine whether the population within the Greater Yellowstone Ecosystem has recovered include estimated population size, distribution of females with cubs, and mortality rates. An estimated 150 grizzly bears occupy ranges that lie partly or entirely within Yellowstone. The number of females producing cubs in the park has remained relatively stable since 1996, suggesting that the park may be at or near ecological carrying capacity for grizzly bears. There were 59 known and probable grizzly bear mortalities in the Greater Yellowstone Ecosystem in 2015. Thirty-four were attributed to human causes. Four were of undetermined cause, 2 were natural deaths, and 19 were still under investigation at the time of this printing. Three human conflicts with grizzly bears occurred inside the park in 2015, and resulted in a human fatality and the removal of a female grizzly and two cubs from the park. (Learn More: Your Safety in Bear Country) Description The grizzly bear’s color varies from blond to black, often with pale-tipped guard hairs. In the Greater Yellowstone Ecosystem, many grizzly bears have a light brown girth band. However, the coloration of black and grizzly bears is so variable that it is not a reliable means of distinguishing the two species. Bears are generally solitary, although they may tolerate other bears when food is plentiful. Grizzlies have a social hierarchy in which adult male bears dominate the best habitats and food sources, generally followed by mature females with cubs, then by other single adult bears. Subadult bears, who are just learning to live on their own away from mother’s protection, are most likely to be living in poor-quality habitat or in areas nearer roads and developments. Thus, young adult bears are most vulnerable to danger from humans and other bears, and to being conditioned to human foods. Food-conditioned bears are removed from the wild population. Diet Bears are generalist omnivores that can only poorly digest parts of plants. They typically forage for plants when they have the highest nutrient availability and digestibility. Although grizzly bears make substantial use of forested areas, they make more use of large, non- forested meadows and valleys than black bears. The longer, less curved claws and larger shoulder muscle mass of the grizzly bear makes it better suited to dig plants from the soil, and rodents from their caches. Grizzly bear food consumption is influenced by annual and seasonal variations in available foods. Over the course of a year, army cutworm moths, whitebark pine nuts, ungulates, and cutthroat trout are the highest-quality food items available. In total, grizzly bears in the Greater Yellowstone Ecosystem are known to consume at least 266 species of plant (67%), invertebrate (15%), mammal (11%), fish, and fungi. They will eat human food and garbage where they can get it. This is why managers emphasize that keeping human foods secure from bears increases the likelihood that humans and bears can peacefully coexist in greater Yellowstone. Bears spend most of their time feeding, especially during “hyperphagia,” the period in autumn when they may gain more than three pounds per day until they enter their dens to hibernate. In years and locations when whitebark pine nuts are available, they are the most important bear food from September through October. However, not all bears have access to whitebark pine nuts, and in the absence of this high-quality food, the bear’s omnivory lets them turn to different food sources. Fall foods also include pondweed root, sweet cicely root, grasses and sedges, bistort, yampa, strawberry, globe huckleberry, grouse whortleberry, buffaloberry, clover, horsetail, dandelion, ungulates (including carcasses), ants, false truffles, and army cutworm moths. From late March to early May, when they come out of hibernation, until mid May, a grizzly bear’s diet primarily consists of elk, bison, and other ungulates. These ungulates are primarily winter-killed carrion (already dead and decaying animals), and elk calves killed by predation. Grizzly bears dig up caches made by pocket gophers. Other items consumed during spring include grasses and sedges, dandelion, clover, spring-beauty, horsetail, and ants. When there is an abundance of whitebark seeds left from the previous fall, grizzly bears will feed on seeds that red squirrels have stored in middens. From June through August, grizzly bears consume thistle, biscuitroot, fireweed, and army cutworm moths in addition to grasses and sedges, dandelion, clover, spring-beauty, whitebark pine nuts, horsetail, and ants. Grizzly bears are rarely able to catch elk calves after mid-July. Starting around mid-summer, grizzly bears begin feeding on strawberry, globe huckleberry, grouse whortleberry, and buffaloberry. By late summer, false truffles, bistort, and yampa are included in the diet as grasses and others become less prominent. Hibernation Bears’ annual denning behavior probably evolved in response to seasonal food shortages and cold weather. Bears hibernate during the winter months in most of the world. The length of denning depends on latitude, and varies from a few days or weeks in Mexico to six months or more in Alaska. Pregnant females tend to den earlier and longer than other bears. Grizzly bear females without cubs in Greater Yellowstone den on average for about five months. Grizzly bears will occasionally re-use a den in greater Yellowstone, especially those located in natural cavities like rock shelters. Dens created by digging, as opposed to natural cavities, usually cannot be reused because runoff causes them to collapse in the spring. Greater Yellowstone dens are typically dug in sandy soils and located on the mid to upper one-third of mildly steep slopes (30–60°) at 6,562–10,000 feet (2,000–3,048 m) in elevation. Grizzly bears often excavate dens at the base of a large tree on densely vegetated, north-facing slopes. This is desirable in greater Yellowstone because prevailing southwest winds accumulate snow on the northerly slopes and insulate dens from sub-zero temperatures. The excavation of a den is typically completed in 3–7 days, during which a bear may move up to one ton of material. The den includes an entrance, a short tunnel, and a chamber. To minimize heat loss, the den entrance and chamber is usually just large enough for the bear to squeeze through and settle; a smaller opening will be covered with snow more quickly than a large opening. After excavation is complete, the bear covers the chamber floor with bedding material such as spruce boughs or duff, depending on what is available at the den site. The bedding material has many air pockets that trap body heat. The body temperature of a hibernating bear, remains within 12°F (22°C) of their normal body temperature. This enables bears to react more quickly to danger than hibernators who have to warm up first. Because of their well-insulated pelts and their lower surface area-to-mass ratio compared to smaller hibernators, bears lose body heat more slowly, which enables them to cut their metabolic rate by 50–60%. Respiration in bears, normally 6–10 breaths per minute, decreases to 1 breath every 45 seconds during hibernation, and their heart rate drops from 40–50 beats per minute during the summer to 8–19 beats per minute during hibernation. Bears sometimes awaken and leave their dens during the winter, but they generally do not eat, drink, defecate, or urinate during hibernation. They live off of a layer of fat built up prior to hibernation. The urea produced from fat metabolism (which is fatal at high levels) is broken down, and the resulting nitrogen is used by the bear to build protein that allows it to maintain muscle mass and organ tissues. Bears may lose 15–30% of their body weight but increase lean body mass during hibernation. Bears sometimes awaken and leave their dens during the winter, but they generally do not eat, drink, defecate, or urinate during hibernation. They live off of a layer of fat built up prior to hibernation. The urea produced from fat metabolism (which is fatal at high levels) is broken down, and the resulting nitrogen is used by the bear to build protein that allows it to maintain muscle mass and organ tissues. Bears may lose 15–30% of their body weight but increase lean body mass during hibernation. Bears emerge from their dens when temperatures warm up and food is available in the form of winter-killed ungulates or early spring vegetation. Greater Yellowstone grizzly bears begin to emerge from their den in early February, and most bears have left their dens by early May. Males are likely to emerge before females. Most bears usually leave the vicinity of their dens within a week of emergence, while females with cubs typically remain within 1.86 miles (3 km) of their dens until late May. Life Cycle Grizzly bears reproduce slowly compared to other land mammals. Females rarely breed before age four, and typically become pregnant once every three years. Grizzly and black bears breed from May through July, and bears may mate with multiple partners during a single season. Because implantation of a fertilized egg in the uterus is delayed, the embryo does not begin to develop until late November or December, about one month after the mother has denned. This appears to allow her to conserve energy until she enters her den, where in late January or early February she gives birth to one or two cubs, sometimes three, rarely four. At birth the cubs are hairless and blind, are about eight inches (20 cm) long, and weigh from 8 to 12 ounces (224–336 g). The cubs do not hibernate. They sleep next to the sow, nurse, and grow rapidly. At ten weeks, grizzly bear cubs weigh about 10–20 pounds (4.5–9.0 kg). Male bears take no part in raising cubs, and may actually pose a threat to younger bears. Grizzly bear cubs usually spend 2½, and sometimes 3½ years with their mother before she or a prospective suitor chases them away so that she can mate again. Females frequently establish their home range in the vicinity of their mother, but male cubs disperse farther. Grizzly Bears, Black Bears, and Wolves Grizzly bears are more aggressive than black bears, and more likely to rely on their size and aggressiveness to protect themselves and their cubs from predators and other perceived threats. Their evolution diverged from a common ancestor more than 3.5 million years ago, but their habitats only began to overlap about 13,000 years ago. Grizzly bears, black bears, and gray wolves have historically coexisted throughout a large portion of North America. The behavior of bears and wolves during interactions with each other are dependent upon many variables such as age, sex, reproductive status, prey availability, hunger, aggressiveness, numbers of animals, and previous experience in interacting with the other species. Most interactions between the species involve food, and they usually avoid each other. Few instances of bears and wolves killing each other have been documented. Wolves sometimes kill bears, but usually only cubs. Wolves prey on ungulates year-round. Bears feed on ungulates primarily as winter-killed carcasses, ungulate calves in spring, wolf-killed carcasses in spring through fall, and weakened or injured male ungulates during the fall rut. Bears may benefit from the presence of wolves by taking carcasses that wolves have killed, making carcasses more available to bears throughout the year. If a bear wants a wolf- killed animal, the wolves will try to defend it; wolves usually fail to chase the bear away, although female grizzlies with cubs are seldom successful in taking a wolf-kill.
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Post by brobear on Mar 24, 2017 3:06:12 GMT -5
www.wildlifepics.eu/weblog/item.php?item=65 The grizzly bear (Ursus arctos ssp.) is any North American subspecies of the brown bear, including the mainland grizzly (Ursus arctos horribilis), the Kodiak bear (Ursus arctos middendorffi), the peninsular grizzly (Ursus arctos gyas) and the recently extinct California grizzly (U. a. californicus) and Mexican grizzly bear (U. a. nelsoni). Specialists sometimes call the grizzly the North American brown bear because the grizzly and the brown bear are one species on two continents. In some places, the grizzly is nicknamed the silvertip bear for the silvery, grizzled sheen in its fur. Since the mainland grizzly is so widespread, it is representative and archetypal for the whole subspecific group. Even so, classification is being revised along genetic lines. Except for females with cubs, grizzlies are normally solitary, active animals, but in coastal areas, grizzlies gather around streams, lakes, rivers, and ponds during the salmon spawn. Every other year, females (sows) produce one to four young (usually two) which are small and weigh only about 500 grams (1 lb). A sow is protective of her offspring and will attack if she thinks she or her cubs are threatened. The word "grizzly" means "grizzled" that is, golden and grey tips of the hair. This is not to be confused with the word "grisly". Nonetheless, after careful study, naturalist George Ord formally classified the California grizzly in 1815, not for its hair, but for its character, Ursus horribilis. Thus Ord made a famous pun. Indeed there were many accounts of grizzlies fighting and beating longhorn bulls. The ancestors of the grizzly bear subspecies were brown bears originating in Eurasia that traveled to North America approximately 50,000 years ago. This is a very recent event, on an evolutionary timescale, causing the North American grizzly bear to be very similar to brown bears inhabiting Siberia and northeast Asia. The closest Eurasian subspecies to the grizzly bears are believed to be the Ussuri brown bear (U. a. lasiotus) for mainland grizzlies and the Kamchatka brown bear (U. a. beringianus) for the coastal Alaskan and Kodiak bears which arrived in North America shortly before the bering land bridge flooded. When it received its scientific name in 1815, the grizzly was classified as a separate species from all other bears. However, modern genetic testing reveals the grizzly to be a subspecies of the brown bear (Ursus arctos). So in Eurasia, it is the "brown bear", in North America, it is the "grizzly". In other words, the grizzly and the brown bear are one species on two continents. Currently, Rausch and others classify three subspecies of the new "North American brown bear", U. a. horribilis, middendorffi, and gyas. But more recent studies of mtDNA suggest that this three-fold division of living grizzlies needs revision. Further testing of Y-chromosomes is required to yield an accurate new taxonomy with different subspecies. Coastal grizzlies, often referred to by the popular but geographically redundant synonym of "brown bear" or "Alaskan brown bear" are larger and darker than inland grizzlies, which is why they, too, were considered a different species from grizzlies. Kodiak grizzly bears were also at one time considered distinct. Thus, at one time there were five different "species" of brown bear, including three in North America. Most adult female grizzlies weigh 130–200 kg (290–440 lb), while adult males weigh on average 180–360 kg (400–790 lb). The average total length in this subspecies is 198 cm (6.50 ft), with an average shoulder height of 102 cm (3.35 ft) and hindfoot length of 28 cm (11 in). Newborn bears may weigh less than 500 grams (1.1 lb). In the Yukon River area, mature female grizzlies can weigh as little as 100 kg (220 lb). One study found that the average weight for an inland male grizzly was around 270 kilograms (600 lb) and the average weight for a coastal male was around 408 kilograms (900 lb). For a female, these average weights would be 136 kilograms (300 lb) inland and 227 kilograms (500 lb) coastal, respectively. On the other hand, an occasional huge male grizzly has been recorded which greatly exceeds ordinary size, with weights reported up to 680 kg (1,500 lb). A large coastal male of this size may stand up to 3 metres (9.8 ft) tall on its hind legs and be up to 1.5 metres (4.9 ft) at the shoulder. Although variable from blond to nearly black, grizzly bear fur is typically brown in color with white tips. A pronounced hump appears on their shoulders; the hump is a good way to distinguish a black bear from a grizzly bear, as black bears do not have this hump. Brown bears are found in Asia, Europe, and North America giving them one of the widest ranges of bear species. In North America, grizzly bears previously ranged from Alaska down to Mexico and as far east as the western shores of Hudson Bay. In North America, the species is now found only in Alaska, south through much of western Canada, and into portions of the northwestern United States including Idaho, Montana, Washington and Wyoming, extending as far south as Yellowstone and Grand Teton National Parks, but is most commonly found in Canada. In Canada, there are approximately 25,000 grizzly bears occupying British Columbia, Alberta, the Yukon, the Northwest Territories, Nunavut, Ontario and the northern part of Manitoba. The Alaskan population of 30,000 individuals is the highest population of any province/state in North America. Populations in Alaska are densest along the coast, where food supplies such as salmon are more abundant. In British Columbia, grizzly bears inhabit approximately 90% of their original territory. There were approximately 25,000 grizzly bears in British Columbia when the European settlers arrived. However, population size significantly decreased due to hunting and habitat loss. In 2008, it was estimated there were 16,014 grizzly bears.
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Post by brobear on Mar 24, 2017 3:12:52 GMT -5
www.nps.gov/yell/learn/yellowstone-grizzly-bear-facts.htm Yellowstone Grizzly Bear Facts From Yellowstone Science 23(2): pages 44-45. Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora Family: Ursidae Subfamily: Ursinae Genus: Ursus (Latin word meaning "bear") Species: arctos (Greek word meaning "bear") Common Names: grizzly bear, brown bear, silvertip Names in Other Languages: Spanish: Oso café/grande, French: Ours brun Group of Bears: sleuth Life Span: 20-30 years; oldest known in GYE 31 years Pelage: from black to brown to light blonde Locomotion: tetrapedal, plantigrade Speed: 35-40 mph Claw Length: average 1.8 inches (45 mm), longest 5.9inches (150 mm);claw length and shape allow efficient digging of foods from the ground but are less efficient for tree climbing than black bear claws Tree Climbing Ability: cubs and younger, smaller bears are proficient tree climbers; however, adult male and female grizzly bears are also capable of climbing trees Tail Length: 3-4.5 inches Body Temperature: 36.5-38.5°C (98-101°F) during active season;34.4-35°C (94-95°F) during hibernation Respiration: 6-10 per minute; <1 per minute during hibernation Heart Rate: 40-50 beats per minute; 8-19 beats per minute during hibernation Eyes: blue at birth, brown as adults, and greenish yellow in headlights in the dark Vision: possibly equal to human vision; exhibits color vision and excellent night vision Genetics: 74 diploid chromosomes Number of Bones: male = 225, female = 224 (not counting the metapodial sesamoid bones and hyoid bones) Number of Teeth: 42 Dental Formulae: I 3/3, C 1/1, P 4/4, M 2/3 = 42 (upper [each side] = 3 incisors, 1 canine, 4 premolars, 2 molars; lower [each side] = 3 incisors, 1 canine, 4 premolars, 3 molars) Feeding Habits: omnivorous carnivore; opportunistic generalist Caloric Requirements: normal (May-Sept): 5,000-8,000 kcal/day; hyperphagia: 20,000 kcal/day; hibernation 4,000 kcal/day Average Body Mass: adult male = 413 lb (187 kg); adult female = 269 lb (122 kg) Heaviest Known Weight in GYE: adult male = 715 lb (324 kg); adult female = 436 lb (198 kg) Estimated Number Currently Living in the GYE: 714 Area Occupied in GYE: 58,000 km2 (22,394 mi2) Average Home Range Size in GYE: males = 874 km2;females = 281 km2 Social Behavior: generally solitary except at concentrated food sources (ungulate carcasses, trout spawning streams, moth aggregation sites, etc.), during courtship, or when accompanied by young Adult Sex Ratio: 50:50 (M/F) Age Composition: 19% cubs, 13% yearlings, 25% subadults (2-4 yrs.), 43% adults Period of Courtship: mid-May through mid-July Delayed Implantation: grizzly bears exhibit obligate delayed implantation or embryonic diapause Gestation: 235 days (implantation of embryo delayed until late November/early December) Birth Period: late January/early February Birth Location: in winter den Den Entry: pregnant females –1st week November;other females –2nd week November;males –2nd week November Average Denning Duration: females with cubs –171 days;other females –151 days;males –131 days Den Emergence: males –4th week March; other females –3rd week April;pregnant females –4th week April Typical Den Types: excavated (i.e., dug) = 91%;natural cavity = 6%;snow = 3% True Hibernators?: yes, although bears are shallow hibernators and do not drop their body temperatures as low as many hibernators, they are considered to be true hibernators Weight Loss During Hibernation: 15-30% of body weight Average Age of First Reproduction (FEMALES): 5.8 years Litter Size: range 1-4 cubs per litter; average 2.04 cubs per litter Interbirth Interval: average = 2.78 years Reproductive Rate: 0.336 female cubs/female/year Survival Rate: cubs = 55%;yearlings = 54%;subadults = 95%; adult females = 95%;adult males = 95% Causes of Mortality (GYE): human causes = 85%;natural causes = 15% Period of Maternal Care: 18 to 42 months;average = 30 months Nursing Characteristics: females have three pairs of functional nipples Bear Milk: 30% fat, 15% protein Cubs' Eyes Open: at approximately 21 days Weaning: nutritional dependence on mother's milk ends at approximately 24 weeks;offspring may continue to nurse occasionally until they separate from their mothers Bibliography Brown, G. 2009. The bear almanac: a comprehensive guide to the bears of the world. Second edition. The Lyons Press, Guilford, CT, USA. Craighead, J.J, J.S. Sumner, and J.A. Mitchell. 1995. The grizzly bears of Yellowstone: their ecology in the Yellowstone Ecosystem, 1959-1992. Island Press, Washington, D.C., USA. Haroldson, M.A., and F.T. van Manen.2015. Estimating number of females with cubs.Pages 11-20 in F.T. van Manen, M.A. Haroldson, and S.C. Soileau, editors. Yellowstone grizzly bear investigations: annual report of the Interagency Grizzly Bear Study Team, 2014.U.S. Geological Survey, Bozeman, Montana, USA. Haroldson, M.A., M.A. Ternent, K.A. Gunther, and C.C. Schwartz. 2002. Grizzly bear denning chronology and movements in the Greater Yellowstone Ecosystem. Ursus 13:29-37. Interagency Grizzly Bear Study Team. 2012. Updating and evaluating approaches to estimate population size and sustainable mortality limits for grizzly bears in the Greater Yellowstone Ecosystem. Interagency Grizzly Bear Study Team, U.S. Geological Survey, Northern Rocky Mountain Science Center, Bozeman, Montana, USA. Schwartz, C.C., M.A. Haroldson, and S. Cherry. 2006. Reproductive performance of grizzly bears in the Greater Yellowstone Ecosystem, 1983-2002. Pages 18-24 in C.C. Schartz,, M.A. Haroldson, G.C. White, R.B. Harris, S. Cherry, K.A. Keating, D. Moody, and C. Servhen, editors. Temporal, spatial, and environmental influences on the demographics of grizzly bears in the Greater Yellowstone Ecosystem. Wildlife Monographs 161. Schwartz, C.C., S.D. Miller, and M.A. Haroldson. 2003. Grizzly bear. Pages 556-586 in G.A. Feldhamer, B.C. Thompson, and J.A. Chapman, editors. Wild mammals of North America: biology, management, and conservation. Second edition. The John Hopkins University Press, Baltimore, Maryland, USA.
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Post by brobear on Mar 24, 2017 11:33:44 GMT -5
Grizzly.
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Post by brobear on Mar 28, 2017 8:22:43 GMT -5
www.discovery.com/tv-shows/great-bear-stakeout/about-grizzlies/naming-the-grizzly/ Naming the Grizzly Scientists were aware of the grizzly long before Lewis and Clark ever set foot in the American West. Some naturalists had even gone so far as to recognize the bear as a new, unique species. For example, naturalist Thomas Pennant had done so in his Arctic Zoology, which was published in London in 1784. However, Pennant and other naturalists relied exclusively on secondhand sources, like explorer's journals, for their scientific descriptions. Meriwether Lewis was the first naturalist to encounter a grizzly bear in the flesh, and his account became the new standard. Lewis and Clark managed to bring back a deceased specimen for scientific study in 1806. The following year, explorer Lieutenant Zebulon Pike delivered two live grizzly bear cubs to President Thomas Jefferson, and these became the first grizzlies ever put on public display in the world. In 1814, DeWitt Clinton published a thesis on the grizzly bear based almost entirely on Lewis's benchmark field observations and the specimen he had brought back from his trip, further paving the way for the animal's official classification. Not long after, naturalist George Ord gave the grizzly the species name Ursus horribilis ord, which means "Ord's horrible bear" - a nod to himself and to Lewis's terrifying, first-person account of the grizzly. In 1815, naturalist Adelbert von Chamisso proposed that the grizzly was simply another type of brown bear and not a distinct species, but it wasn't until 1851 that biologist Alexander Theodor von Middendorff recognized all brown bears as the species Ursus arctos. That same year, Middendorff gave the grizzly the subspecies name Ursus arctos horribilis, which means "horrible northern bear." For over a century, scientists recognized several North American brown bear subspecies. That changed in 1953 when biologist R.L. Rausch designated all brown bears not living on Alaska's Kodiak, Afognak and Shuyak islands as grizzlies. Kodiak bears remained Ursus arctos middendorffi, which means "Middendorff's northern bear."
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Post by brobear on Apr 23, 2017 10:30:44 GMT -5
Continued.... The following census, taken in 1946 and 1952 by the U.S.Fish and Wildlife Service, places the grizzly population within the bounds of the United States as listed below. These bears were known to be living at those times within the bounds of our national parks and monuments, Indian reservations, national and state forests, and federal, state, and private lands. States years and grizzly numbers: Washington... 1946-3 / 1952-0 / 1959-10 Idaho..... 1946-60 / 1952-69 / 1959-49 Colorado... 1946-26 / 1952-32 / 1959-17 Montana.... 1946-772 / 1952-758 / 1959-550 Wyoming.... 1946-487 / 1952-349 / 1959-230 Total grizzlies in U.S.A: 1946 = 1348 1952 = 1208 1959 = 856 This total ( 1959 ) compared with the 1952 total shows a decrease of 352 grizzlies, a depletion of one-forth of the grizzly population in only seven years. One can readily see that these great bears are swiftly on the decline and within another few years, unless something is done quickly to protect them, they will be completely annihilated. ( This census was taken before Jan. 1959 when Alaska became a state ).
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Post by brobear on Apr 23, 2017 11:28:51 GMT -5
Notorious Grizzly Bears by W.P. Hubbard - 1960 - Pelage and Character - Coloration. Research confirms that the color of the grizzly conforms with no known law of coloration. I have seen grizzlies in all shades of color, ranging from almost jet black through the browns and creams to practically white. However, I have never seen, heard, or read of an albino grizzly. Bears with large white markings are referred to as pintos, or color freaks. One rarely finds two grizzlies of the same color. It is not uncommon to see an old she-bear with three cubs, each of a different color; for example, one a dark brown, verging almost upon black, a second of light buff, and the third almost white, or white as far back as the shoulders. I have seen only one litter of cubs that were all the same color as their mother. The reason for this great variety of color is unknown. It is, however, an indisputable fact, and typical of the species throughout its range.
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Post by brobear on Apr 23, 2017 12:19:21 GMT -5
Notorious Grizzly Bears by W.P. Hubbard - 1960 - Pelage and Character - Matings and Cubs. Grizzlies mate every second or third year. On the average a grizzly has either two or three cubs to a litter, usually only two. Once I saw a grizzly with four cubs, and on three occasions one with but one. I have seen a good many with two and several with three. The mating time of these bears throughout the northwest runs according to locality, from about the middle of June until about the first of August. I cannot say whether individual males and females deliberately hunt each other out during the mating season, pair off and stay together for a few weeks, or whether they meet by chance and separate quickly. The latter is the more credible.
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Post by brobear on Apr 23, 2017 23:42:10 GMT -5
Notorious Grizzly Bears by W.P. Hubbard - 1960 - Pelage and Character - Denning Up. Cub bears frequently den together the first winter they are on their own, but after that they break up and den alone. Adult bears den singly. The male hibernates earlier than the female and comes out of hibernation earlier. The grizzly likes to den in high country, near, at, or above the timberline. Their dens are most often located on northern slopes, or in the shaded recesses of narrow canyons, or deep ravines. This is due to the fact that northern slopes and such locations receive less sun and consequently the bears are out of hibernation before melting snow water soaks the den. In the colder parts of Alaska and Canada, old bear men assure me that grizzlies hibernate in October, while those in warmer climates along the Alaskan coast may remain out until late November or early December. In the western states, where climate conditions are milder, they usually den up in November or December, coming out in late April or early May. In the warmer climates of the southwest, they are known to come out as early as late February or mid-March.
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