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Carnivorous and Omnivores Animals, Excluding Felids
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Bears
Bear Interactions with Other Predators
Bear Interactions with Other Predators
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Bear Interactions with Other Predators
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The Great Bear Almanac by Gary Brown... A grizzly bear was observed moving aside to avoid a skunk.
"A mountaineer friend of Seton's ( Ernest Thompson ) told of two wolverines driving a black bear from the remains of an elk," noted Adolph Murie. Murie observed a wolverine chase a grizzly bear off a carcass and, according to another reliable account, a Russian brown bear was driven away from a carcass by a wolverine. Frank Dufresne relates the story of a thirty-pound wolverine accosting a grizzly bear on a narrow trail. The bear was ten times the size of the wolverine, but when the wolverine screeched, the young bear departed.
The Grizzly by Enos A. Mills - There is marked difference in the ordinary ways of the black and the grizzly. The grizzly is energetic, thorough, works hard, and takes life rather seriously; while the black bear is lazy, careless, does no more work each day than is necessary, and is more playful. The grizzly's hibernating-den is usually a substantial complete affair, while that of the black bear is more or less of a makeshift. The black bear likes to play with other bears, while the grizzly enjoys playing alone. The black bear climbs a tree easily and often sleeps in a tree-top; the grizzly bear rarely climbs after he passes cubhood.
Bear Almanac by Gary Brown.
Wolf - Wolf-bear relationships have been considered neutral, with only occasional conflicts that are based on defense of home site, food, or young by each species. A wolf and a grizzly bear have fed side by side on a caribou carcass, while at other times a grizzly has fought off a pack of wolves to defend its food, and they each have killed the other.
The Beast that walks like Man by Harold McCracken.
Here in Yellowstone, as elsewhere in Montana to the north, there are also more promising developments. Since 1995, there's been a new and enormously interesting scent on those first breezes that the bears inhale when they emerge. They once again, for the first time in several decades, share their domain with a sizable population of wolves, who not only make life exciting in general but also unwillingly provide the bears with a lot of free meat when bears take a fresh kill away from a wolf pack or scavenge an older kill. Life continues to change for the grizzly bears, and, as with the changes in human attitudes about them, the changes are often good.
Of bears and berries: Return of wolves aids grizzly bears in Yellowstone
by Staff Writers Corvallis OR (SPX) Jul 30, 2013 grizzly-bear-yellowstone-national-park-l This is a grizzly bear in Yellowstone National Park. Photo courtesy of Yellowstone National Park. A new study suggests that the return of wolves to Yellowstone National Park is beginning to bring back a key part of the diet of grizzly bears that has been missing for much of the past century - berries that help bears put on fat before going into hibernation. It's one of the first reports to identify the interactions between these large, important predators, based on complex ecological processes. It was published by scientists from Oregon State University and Washington State University in the Journal of Animal Ecology. The researchers found that the level of berries consumed by Yellowstone grizzlies is significantly higher now that shrubs are starting to recover following the re-introduction of wolves, which have reduced over-browsing by elk herds. The berry bushes also produce flowers of value to pollinators like butterflies, insects and hummingbirds; food for other small and large mammals; and special benefits to birds. The report said that berries may be sufficiently important to grizzly bear diet and health that they could be considered in legal disputes - as is white pine nut availability now - about whether or not to change the "threatened" status of grizzly bears under the Endangered Species Act. "Wild fruit is typically an important part of grizzly bear diet, especially in late summer when they are trying to gain weight as rapidly as possible before winter hibernation," said William Ripple, a professor in the OSU Department of Forest Ecosystems and Society, and lead author on the article. "Berries are one part of a diverse food source that aids bear survival and reproduction, and at certain times of the year can be more than half their diet in many places in North America." When wolves were removed from Yellowstone early in the 1900s, increased browsing by elk herds caused the demise of young aspen and willow trees - a favorite food - along with many berry-producing shrubs and tall, herbaceous plants. The recovery of those trees and other food sources since the re-introduction of wolves in the 1990s has had a profound impact on the Yellowstone ecosystem, researchers say, even though it's still in the very early stages. "Studies like this also point to the need for an ecologically effective number of wolves," said co-author Robert Beschta, an OSU professor emeritus. "As we learn more about the cascading effects they have on ecosystems, the issue may be more than having just enough individual wolves so they can survive as a species. In some situations, we may wish to consider the numbers necessary to help control overbrowsing, allow tree and shrub recovery, and restore ecosystem health." As wolves help reduce elk numbers in Yellowstone and allow tree and shrub recovery, researchers said, this improves the diet and health of grizzly bears. In turn, a healthy grizzly bear population provides a second avenue of control on wild ungulates, especially on newborns in the spring time. Yellowstone has a wide variety of nutritious berries - serviceberry, chokecherry, buffaloberry, twinberry, huckleberry and others - that are highly palatable to bears. These shrubs are also eaten by elk and thus likely declined as elk populations grew over time. With the return of wolves, the new study found the percentage of fruit in grizzly bear scat in recent years almost doubled during August. Because the abundant elk have been an important food for Yellowstone grizzly bears for the past half-century, the increased supply of berries may help offset the reduced availability of elk in the bears' diet in recent years. More research is needed regarding the effects of wolves on plants and animals consumed by grizzly bears. There is precedent for high levels of ungulate herbivory causing problems for grizzly bears, who are omnivores that eat both plants and animals. Before going extinct in the American Southwest by the early 1900s, grizzly bear diets shifted toward livestock depredation, the report noted, because of lack of plant-based food caused by livestock overgrazing. And, in the absence of wolves, black bears went extinct on Anticosti Island in Canada after over-browsing of berry shrubs by introduced while-tailed deer. Increases in berry production in Yellowstone may also provide a buffer against other ecosystem shifts, the researchers noted - whitebark pine nut production, a favored bear food, may be facing pressure from climate change. Grizzly bear survival declined during years of low nut production. Livestock grazing in grizzly bear habitat adjacent to the national park, and bison herbivory in the park, likely also contribute to high foraging pressure on shrubs and forbs, the report said. In addition to eliminating wolf-livestock conflicts, retiring livestock allotments in the grizzly bear recovery zone adjacent to Yellowstone could benefit bears through increases in plant foods.
The Grizzly by Enos A. Mills.
An old grizzly pursued by wolves once gave me a fearful exhibition of nature. He came running across as opening in the southern end of North Park with several wolves close in pursuit. He acted as though away from home - hard pressed, bewildered, and in a strange territory. The wolves were crowding him closely as he reached the edge of the woods. With a sudden move he wheeled and struck at the one in the lead. Instantly the others were around him, snarling and snapping. The grizzly wheeled and struck quickly to right and left, striking outward and downward somewhat after the fashion of a cat striking at a near-by object. Then he turned and ran on. A few miles farther on he again crossed an opening. Fresh wolves were now in pursuit. I saw several of the pack lying down, panting and resting. The grizzly had no rest, he was hard pressed. At one place, closely crowded, he backed up in the corner of a cliff and here put up such a fight that he drove the wolves off for the time being. He killed one and badly injured two of them. Towards evening he took refuge in a den-like place for which he evidently had been heading. The following morning a number of the wolves were gone, but the others were waiting for the grizzly in front of the den.
http://shaggygod.proboards.com/board/2/additional-prey
Rakov, N.V. (1970) Causes of mortality of the wild boar and its interrelation with predators in the Amur territory. Zoologicheskii Zhurnal "In years of crop failure, brown bears are well adapted to the hunt wild boars.Bears do kill boar of all ages and classes.(Including adult and prime male wild boar)"
California Grizzly by Tracy I. Storer and Lloyd Tevis, Jr.
The feet of bears are large because the animals are plantigrade, the palm or sole as well as the toes being provided with durable pads that regularly make contact with the ground ( fig. 7 ). In this respect they differ from the speedier dogs, cats, and other lithe carnivores that habitually run on their toes. The forefoot of grizzlies - and that of black bears - has a large pad on the palm that is wider than long and somewhat rectangular. Each of the five toes has a small oval pad. The hind foot of the California grizzly was a huge structure in fully adult males. For example, that of the big individual which served as the type of Ursus magister ( USNM 160155 ) measured 12 inches in length without the claws, and 8 inches in greatest breadth. The sole pad is crudely triangular, with the base foremost against the pads of the five toes. All the pads are surfaced with tough, cornified epidermis over a substantial mass of resistant connective tissue. This covering of the foot is the sturdy, self-renewing "shoe." The front claws of grizzlies, as compared with those of black bears, are heavier, longer, broader, and only slightly curved. They serve the grizzlies in their extensive digging operations for bulbs, roots, and rodents and in fighting. Many human beings were deeply gashed by these great hooks that are powered by heavy arm and shoulder muscles. The length and size of the claws vary with age, and possibly bears of different regions had some differences in relative proportions and dimensions of these members. The activities of the animals also affected the claws. According to X'antus, grizzlies near Fort Tejon had claws much worn from digging. Of the grizzlies in the Rockies, Mills ( 1919 : 91 ) wrote that when the animals entered hibernation the claws were worn, blunt, and broken, but when they emerged from the winter rest period the claws were long and moderately pointed. Replacement growth would not have been conspicuous in lowland California grizzlies that did not hibernate.
The Bear Almanac by Gary Brown.
SHOULDER HUMP - Brown bears have a hump between their shoulders that is covered with long hair and is normally a reliable means of species identification. The long hair often accentuates the hump when the hackles are raised. This distinguishing feature is a distinctive mass of muscle that provides brown bears with their exceptional digging ability and the powerful striking force of their forepaws.
Man Meets Grizzly by Young and Beyers.
When mature, a grizzly has claws from four to seven inches long; not curved and sharp like the black bear's, but large, slightly curved, and somewhat concave on the underside, very much resembling a chisel, and well-adapted for digging, tearing logs apart, and fighting, when necessary. With these unique tools the grizzly will remove huge quantities of earth and rocks quickly in pursuit of a rodent morsel or dig a pit large enough to bury the carcass of a range bull, which he carefully covers up to insure a future meal for himself. And of course the claws are formidable weapons in combat, cutting like razors and strong as steel.
Wild Guide - Bears by Charles Fergus.
Grizzly Bear ( Ursus arctos )... When naturalist Terry Domico photographed a large male that researchers had caught in a leg snare, he watched the bruin vent its frustration on a 4-inch-diameter pine, snapping it off with a single bite. The bear has also chewed through several 6-and-8-inch-diameter trees nearby. A grizzly bear's head is large. Its face has a "dished," or concave, appearance, with the muzzle ending in a broad, upturned snout. The grizzly possesses massive forelegs and a huge chest. A hump of muscle between the front shoulders provides power to the forelegs, for digging out food or excavating dens. A grizzly's front claws - digging tools par excellence - are longer than its rear claws and may be 3 to 4.5 inches or more in length. The claws are usually pale in color. If a bear's claws are prominent enough that you can see them while the bear is walking, you are probably looking at a grizzly rather than a brown-phase black bear. The rear track of a big grizzly can be 14 inches long and 8 inches wide.
Brown Bear by Melissa Gish.
Brown bears have a powerful bite force. Even a great white shark's bite, at 690 pounds of pressure per square inch ( 48.5 kg/cm ), or psi, is no match for a brown bear's bite at 1,200 psi ( 84.4 kg/cm ). The bones in the legs and paws are thick, and each paw has five digits ending in sharp claws that can be up to six inches long. The force that a bear can excert with its front paws is enormous. One swipe can behead a moose or crush its spine.
Nature's Deadliest, The Grizzly Bear by Lisa Owings.
A grizzly bear's bite is strong enough to crush a bowling ball. A grizzly bear's claws can grow up to 4 inches ( 10 cm ) long. That's almost as long as a human finger. *Note: I own three grizzly claws. The longest of them is about 5 inches long, but one slightly shorter is thicker in size.
The Bears of Katmai by Matthias Breiter.
For a long-distance chase, they are much too heavy. Nobody would call them fleet-footed; their legs are relatively short, but they are still much more mobile than are the limbs of typical runners. As they are packed heavily with muscle, the stout forelegs of bears are capable of producing great force over a much wider range of motion than those of cats and dogs. The mobility and strength of their limbs are of great importance for bears in their search for food, such as digging for roots. The animals may not be able to escape danger by fleeing, but as a rule they are quite capable of defending themselves through brute force.
First posted by Grraahh - http://shaggygod.proboards.com/
Text extract from Naturalist Terry Domico: "The brown bear is stout and rather chunky in shape, with a large hump of fat and muscle over the shoulders and very long claws. It has a wide, massive head that some people describe as being somewhat "dish faced" in appearance. That big head is equipped with extremely powerful jaws. I once saw a big male, trapped in a leg snare set by researchers, take out its frustration on some neighboring trees. In one bite he bit completely through a 4-inch (10-cm) -diameter pine, snapping it off. It also chewed through several 6- and 8-inch (15- and 20-cm) -diameter trees. One stump looked as though it had been dynamited. When we slammed the sharp end of a geologist's pick into the trunk of one of those trees, it only penetrated about 1.5 inches (3.8 cm) into the wood." |
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