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Brown Bear
Temporal range: Late Pleistocene – Recent
Scientific classification
Kingdom:
Animalia
Phylum:
Chordata
Class:
Mammalia
Order:
Carnivora
Family:
Ursidae
Genus:
Ursus
Species:
U. arctos
Binomial name
Ursus arctos
Linnaeus, 1758
Ursus arctos range map.
For the children's book, see Brown Bear, Brown Bear, What Do You See?

The brown bear (Ursus arctos) is a large bear distributed across much of northern Eurasia and North America. It weighs 100 to 680 kilograms (220–1,500 lb) and its largest subspecies, the Kodiak Bear, rivals the polar bear as the largest member of the bear family,[2] and as the largest land based predator.[3]

While the brown bear's range has shrunk, and it has faced local extinctions, it remains listed as a least concern species by the IUCN, with a total population of approximately 200,000. Its principal range countries are Russia, the United States (especially Alaska), Canada, the Carpathian region (especially Romania), and Finland where it is the national animal.

The species primarily feeds on vegetable matter, including roots and fungi. Fish are a primary source of meat. It also eats small land mammals and occasionally larger mammals, such as deer. Adult brown bears can match wolf packs and large felines, often driving them off their kills.

It is sometimes referred to as the bruin, from Middle English, based on the name of the bear in History of Reynard the Fox, translated by William Caxton, from Middle Dutch bruun or bruyn, meaning brown.[4]

Taxonomy

There is little agreement on classification of brown bears. Some systems have proposed as many as 90 sub-species, while recent DNA analysis has identified as few as five clades.[5] DNA analysis recently revealed that the identified subspecies of brown bears, both Eurasian and North American, are genetically quite homogeneous, and that their genetic phylogeography does not correspond to their traditional taxonomy.[6] One subspecies appears to be more closely related to the polar bear than to other brown bears.[6] This species is called "clade I" by Waits, et al., and is part of the subspecies identified as U. a. sitkensis, by Hall and as U. a. dalli by Kurtén. The subspecies have been listed as follows:

Polar/Brown Bear Hybrid, Rothschild Museum, Tring

Hybrids

Main article: Grizzly–polar bear hybrid

A grizzly–polar bear hybrid (known as a Pizzly Bear or Grolar bear) is a rare ursid hybrid resulting from a union of a brown bear and a polar bear. It has occurred both in captivity and in the wild. In 2006, the occurrence of this hybrid in nature was confirmed by testing the DNA of a strange-looking bear that had been shot in the Canadian arctic.[7][8][9] Previously, the hybrid had been produced in zoos and was considered a "cryptid" (a hypothesized animal for which there is no scientific proof of existence in the wild).

Description

A Eurasian Brown Bear running. Brown bears can be fast runners despite their size, capable of speeds of up to 64 km/h (40 mph)
Illustration of a brown bear skull

Brown bears have furry coats in shades of blonde, brown, black, or a combination of those colors. The longer outer guard hairs are often tipped with white or silver, giving a "grizzled" appearance. Their tail is 4–5 inches (10–13 centimetres) long.[10] Like all bears, brown bears are plantigrades and can stand up on their hind legs for extended periods of time. Brown bears have a large hump of muscle over their shoulders which distinguishes them from other species.[11] Brown bears are very powerful, and can break the backs and necks of large prey. The forearms end in massive paws with claws up to 15 cm (5.9 in) in length which are mainly used for digging. The claws are not retractable, and have relatively blunt points. Their heads are large and round with a concave facial profile, a characteristic used to distinguish them from other bears. Males are 38–50% larger than females.[10]

The normal range of physical dimensions for a brown bear is a head-and-body length of 1.7 to 2.8 meters (5.6 to 9.2 ft) and a shoulder height of 90 to 150 centimeters (35–60 in). The smallest subspecies is the Eurasian Brown Bear whose mature females weigh as little as 90 kg (200 lb).[12] Barely larger, Grizzly Bears from the Yukon region (which are a third smaller than most grizzlies) can weigh as little as 100 kg (220 lb) in the spring[13] and the Syrian Brown Bear, with mature females weighing as little as 150 kg (330 lb). The largest subspecies are the Kodiak Bear and the Kamchatka Brown Bear. It is not unusual for large male Kodiak Bears to stand over 3 m (9.8 ft) while on their hind legs, and to weigh up to 680 kg (1,500 lb).[14] The largest wild Kodiak Bear on record weighed over 1,100 kilograms (2,400 lb).[10] Bears raised in zoos are often heavier than wild bears because of regular feeding and limited movement. In zoos, bears may weigh up to 900 kilograms (2,000 lb), one example being "Goliath" from New Jersey's Space Farms Zoo and Museum. Another example is Kodiak brown bear "Barbucha" at the zoo in Duisburg, who weighs 1000 kilograms (2200 lb).[15] Size seems related to food availability, and subspecies distinctions is more related to nutrition than geographical location.[16]

Despite their size, some brown bears have been clocked at speeds in excess of 64 km/h (40 mph).[17]

One of the subspecies of the brown bear, the Kodiak Bear, which is native to Kodiak Island, matches the polar bear as the largest member of the bear family,[2] and as the largest land predator.[3] The hides and skulls of the two species are comparable in size, thus making morphological comparisons difficult as it is often difficult to weigh wild specimens.[3]

Distribution and habitat

Brown Bear at Brooks Falls

There are about 200,000 brown bears in the world. The largest populations are in Russia with 120,000, the United States with 32,500, and Canada with 21,750. 95% of the brown bear population in the United States is in Alaska, though in the lower 48 they are repopulating slowly but steadily along the Rockies and plains. Although many people hold on to the belief that some brown bears may be present in Mexico and the Atlas Mountains of Morocco, both are almost certainly extinct. The last Mexican brown bear was shot in 1960. In Europe, there are 14,000 brown bears in ten fragmented populations, from Spain in the west, to Russia in the east, and from Scandinavia in the north to Romania, Bulgaria, Slovakia (with about 800–900 animals), and Greece (with about 200 animals) in the south. They are extinct in the British Isles, extremely threatened in France and Spain, and in trouble over most of Central Europe. The Carpathian brown bear population is the largest in Europe outside Russia, estimated at 4,500 to 5,000 bears. Scandinavia is home to a large bear population, with an estimated 2,500 (range 2,350–2,900) in Sweden, 840 in Finland, and 70 in Norway. Another large and relatively stable population of brown bears in Europe, consisting of 2,500–3,000 individuals, is the Dinaric-Pindos (Balkans) population, with contiguous distribution in North-East Italy, Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro, Macedonia, Albania, and Greece.[18]

Brown bears were once native to Asia, the Atlas Mountains in Africa, Europe, and North America,[19] but are now extinct in some areas and their populations have greatly decreased in other areas. They prefer semi-open country, usually in mountainous areas.

Brown bears live in Alaska, east through the Yukon and Northwest Territories, south through British Columbia and through the western half of Alberta. Small populations exist in the Greater Yellowstone Ecosystem of northwest Wyoming (with about 600 animals), the Northern Continental Divide Ecosystem of northwest Montana (with about 400–500 animals), the Cabinet-Yaak Ecosystem of northwest Montana and northeast Idaho (with about 30–40 animals), the Selkirk Ecosystem of northeast Washington and northwest Idaho (with about 40–50 animals), and the North Cascades Ecosystem of north-central Washington (with about 5–10 animals). These five ecosystems combine for a total of roughly 1,200 wild grizzlies still persisting in the contiguous United States. Unfortunately, these populations are isolated from each other, inhibiting any genetic flow to occur between ecosystems. This poses one of the greatest threats to the future survival of the grizzly bear in the contiguous United States.

The population of brown bears in the Pyrenees mountain range between France and Spain is so low, estimated at 14 to 18 with a shortage of females, that bears, mostly female, from Slovenia were released in spring 2006 to reduce the imbalance and preserve the species' presence in the area, despite protests from French farmers.

A little population of brown bears (Ursus arctos marsicanus) still lives in central Italy (Apennine mountains, Abruzzo and Latium) with no more than 70 speciemens, protected by severe laws but endangered for the strong human presence in the area.

In Arctic areas, the potential habitat of the brown bear is increasing. The warming of that region has allowed the species to move farther north into what was once exclusively the domain of the polar bear. In non-Arctic areas, habitat loss is blamed as the leading cause of endangerment, followed by hunting.

North American brown bears seem to prefer open landscapes, whereas in Eurasia they inhabit mostly dense forests. It is thought that the Eurasian bears which colonized America were tundra-adapted. This is indicated by brown bears in the Chukotka Peninsula on the Asian side of Bering Strait, which are the only Asian brown bears to live year-round in lowland tundra like their American cousins.[20]

Behavior

The brown bear is primarily nocturnal. In the summer it gains up to 180 kilograms (400 lb) of fat, on which it relies to make it through winter, when it becomes very lethargic. Although they are not full hibernators, and can be woken easily, both sexes like to den in a protected spot such as a cave, crevice, or hollow log during the winter months. Brown bears are mostly solitary, although they may gather in large numbers at major food sources and form social hierarchies based on age and size.[21]

Reproduction

File:Bear and cubs fapas.jpg
Female Cantabrian brown bear and cubs. With permission of Fapas (Conservation NGO - Foundation for the Protection of Wild Animals)

The mating season is from late May to early July. Being serially monogamous, brown bears remain with the same mate from several days to a couple of weeks. Females mature sexually between the age of 5 and 7 years, while males usually mate a few years later when they are large and strong enough to successfully compete with other males for mating rights.

Through the process of delayed implantation, a female's fertilized egg divides and floats free in the uterus for six months. During winter dormancy, the fetus attaches to the uterine wall. The cubs are born eight weeks later, while the mother sleeps. If the mother does not gain enough weight to survive through the winter, the embryo does not implant and is reabsorbed into the body. The average litter has one to four cubs, usually two. There have been cases of bears with five cubs, though sometimes females adopt strange cubs. Older females tend to give birth to larger litters. The size of a litter also depends on factors such as geographic location and food supply. At birth, the cubs are blind, toothless, hairless, and weigh less than 1 pound. They feed on their mother's milk until spring or even early summer depending on climate conditions. At this time, the cubs weigh 15 to 20 pounds and have developed enough to follow her and begin to forage for solid food.

Cubs remain with their mother from two to four years, during which time they learn survival techniques, such as which foods have the highest nutritional values and where to attain them; how to hunt, fish, and defend themselves; and where to den. The cubs learn by following and imitating their mother's actions during the period they are with her.[22] Brown bears practice infanticide.[23] An adult male bear may kill the cubs of another bear either to make the female sexually receptive or simply for consumption. Cubs flee up a tree when they see a strange male bear, and the mother defends them even though the male may be twice her size.

Dietary habits

Brown bear feeding on salmon

They are omnivores and feed on a variety of plant products, including berries, roots, and sprouts, fungi as well as meat products such as fish, insects, and small mammals. Despite their reputation, most brown bears are not highly carnivorous as they derive up to 90% of their dietary food energy from vegetable matter.[24] Their jaw structure has evolved to fit their dietary habits. Their diet varies enormously throughout their differing areas based on opportunity. For example, bears in Yellowstone eat an enormous number of moths during the summer, sometimes as many as 40,000 in a day, and may derive up to half of their annual food energy from these insects.[25] In some areas of Russia and Alaska, brown bears feed mostly on spawning salmon, whose nutrition and abundance explains the enormous size of the bears in these areas. Brown bears also occasionally prey on large mammals, such as deer, elk, moose, caribou, and bison. When brown bears attack these animals, they tend to choose the young ones as they are easier to catch. When hunting, the brown bear uses its sharp canine teeth for neck-biting its prey. On rare occasions, bears kill by hitting their prey with their powerful forearms which can break the necks and backs of large prey, such as bison. They also feed on carrion and use their size to intimidate other predators such as wolves, cougars, tigers, and black bears from their kills.

Interspecific predatory relationships

Brown bears often use their large size for intimidation when a kill or a territory is in dispute with a large predator of another species. Sometimes the conflict will escalate to the point of violence, but usually threat displays are sufficient since most animals try to avoid potential bodily harm. However, the massive strength and size of the brown bear will usually result in it winning violent conflicts. In situations where the interspecies conflict turns deadly, brown bears may also eat the competitor despite it not being the primary reason for attack.

Brown bears regularly intimidate wolves away from their kills. In Yellowstone National Park, brown bears pirate wolf kills so often that Yellowstone's Wolf Project Director Doug Smith wrote: "It's not a matter of if the bears will come calling after a kill, but when." Though conflict over carcasses is common, on rare occasions the two predators tolerate each other on the same kill. Given the opportunity, both species prey on each other's cubs.[26]

Adult bears are generally immune from predatory attacks from anything other than another bear. Some bears emerging from hibernation will seek out tigers in order to steal their kills.[27] However, in the Russian Far East brown bears, along with smaller Asiatic black bears constitute 5–8% of the diet of Siberian tigers. In particular, the brown bear's input is estimated to be 1–1.5%.[28] Tiger attacks on bears tend to occur when ungulate populations decrease. Large adult bears are generally immune to tiger attacks in summer but have been killed in their dens in winter.[29] There are records of bears killing tigers, either in self defense, or in disputes over kills or for consumption.[30][31]

Brown bear being followed by a wolf

Brown bears usually dominate other bear species in areas where they coexist. Due to their smaller size, American Black Bears are at a competitive disadvantage over brown bears in open, non-forested areas. Although displacement of black bears by brown bears has been documented, actual interspecific killing of black bears by brown bears has only occasionally been reported. Confrontation is mostly avoided thanks to the black bear's diurnal habit and preference for heavily forested areas, as opposed to the brown bear's largely nocturnal habit and preference for open spaces.[32]

There has been a recent increase in interactions between brown bears and polar bears, theorized to be caused by climate change. Brown bears have been seen moving increasingly northward into territories formerly claimed by polar bears. Brown bears tend to dominate polar bears in disputes over carcasses,[33] and dead polar bear cubs have been found in brown bear dens.[34] Giant Panda cubs have also been reportedly eaten by brown bears.[10]

Relationship with humans

Front paw imprint.
Rear paw imprint.

Bears become attracted to human-created food sources such as garbage dumps, litter bins, and dumpsters; they venture into human dwellings or barns in search of food as humans encroach into bear habitats. In the U.S., bears sometimes kill and eat farm animals. When bears come to associate human activity with a "food reward", they are likely to continue to become emboldened; the likeliness of human-bear encounters increases, as they may return to the same location despite relocation. The saying, "a fed bear is a dead bear", has come into use to popularize the idea that allowing bears to scavenge human garbage, such as trash cans and campers' backpacks, pet food, or other food sources that draw the bear into contact with humans can result in a bear's death.

Relocation of the bear has been used to separate the bear from the human environment, but it does not address the problem of the bear's newly learned association of humans with food or the environmental situations which created the human habituated bear. "Placing a bear in habitat used by other bears may lead to competition and social conflict, and result in the injury or death of the less dominant bear."[35]

Yellowstone National Park, an enormous reserve located in the Western United States, contains prime habitat for the Grizzly Bear (Ursus arctos horribilis), and due to the enormous number of visitors, human-bear encounters are common. The scenic beauty of the area has led to an influx of people moving into the area. In addition, because there are so many bear relocations to the same remote areas of Yellowstone, and because male bears tend to dominate the center of the relocation zone, female bears tend to be pushed to the boundaries of the region and beyond. As a result, a large proportion of repeat offenders, bears that are killed for public safety, are females. This creates a further depressive effect on an already endangered species. The grizzly bear is officially described as threatened in the U.S. Though the problem is most significant with regard to grizzlies, these issues affect the other types of brown bear as well.

In Europe, part of the problem lies with shepherds; over the past two centuries, many sheep and goat herders have gradually abandoned the more traditional practice of using dogs to guard flocks, which have concurrently grown larger. Typically they allow the herds to graze freely over sizeable tracts of land. As bears reclaim parts of their range, they may eat livestock. In some cases, the shepherds shoot the bear thinking that their livelihood is under threat. Many are now better informed about the ample compensation available and will make a claim when they lose livestock to a bear.

Legal status

Bear encounters

There are an average of two fatal attacks by bears per year in North America.[37] In Scandinavia, there are only four known cases since 1902 of bear encounters which have resulted in death. The two most common causes for bear attack are surprise and curiosity.[38] Some types of bears, such as polar bears, are more likely to attack humans when searching for food, while American Black Bears are much less likely to attack.

The Alaska Science Center ranks the following as the most likely reasons for bear attacks:[38]

  1. Surprise
  2. Curiosity
  3. Invaded personal space (this includes a mother bear protecting her young)
  4. Predatory
  5. Hunting wounded
  6. Carcass defense
  7. Provoked charge

Aggressive behaviour in brown bears is favoured by numerous selection variables. Unlike the smaller black bears, adult brown bears are too large to escape danger by climbing trees, so they respond to danger by standing their ground and warding off their attackers. Increased aggressiveness also assists female brown bears in better ensuring the survival of their young to reproductive age.[39] Mothers defending cubs are the most prone to attacking, being responsible for 70% of brown bear-caused human fatalities in North America.[40]

History of defense from bears

A study by Canadian and US researchers has found pepper spray to be more effective at stopping aggressive bear behavior than guns, working in 92% of studied incidents vs 67% for guns.[41] Carrying pepper spray is highly recommended by many authorities when traveling in bear country, however carrying two means of deterrent, one of which is a large caliber gun, is also advised. Solid shotgun slugs, or three buckshot rounds, or a semi-auto pistol of .45 caliber or more is suggested if a heavy hunting rifle is not available. Guns remain a viable, last resort option to be used in defense of life from aggressive bears.[42] Too often, people do not carry a proper caliber weapon to neutralize the bear. According to the Alaska Science Center, a 12 gauge shotgun with slugs has been the most effective weapon. There have been fewer injuries as a result of only carrying lethal loads in the shotgun, as opposed to deterrent rounds. State of Alaska Defense of Life or Property (DLP) laws require you to report the kill to authorities, and salvage the hide, skull, and claws.[43] Campers are often told to wear bright colored red ribbons and bells, and carry whistles to ward off bears. They are told to look for grizzly scat in camping areas, and be careful to carry the bells and whistles in those areas. Grizzly scat is easy to differentiate from black bear scat. Black bear scat is full of fruit and pine cones; grizzly scat is not. If a bear is killed near camp, the bear's carcass must be adequately disposed of, including entrails and blood if possible. Failure to move the carcass has often resulted in it attracting other bears and further exacerbating a bad situation. Better still - move your camp immediately.

In culture

Smokey Bear

The brown bear is perhaps the archetypal bear.

Many Native American tribes both respected and feared the brown bear even thinking of it as a god.[44]

Smokey Bear has become a part of American culture since his introduction in 1944. Known to almost all Americans, he and his message, "Only You Can Prevent Forest Fires" (updated in 2001 to "Only You Can Prevent Wildfires") has been a symbol of preserving woodlands.[45] Smokey wears a hat similar to one worn by many U.S. state police officers, giving rise to the CB slang "bear" or "Smokey" for the highway patrol.

See also

References

  1. ^ Template:IUCN2008
  2. ^ a b "Polar bear, (Ursus maritimus)" (PDF). U.S. Fish and Wildlife service. Retrieved 2008-03-22. Appearance. The polar bear is the largest member of the bear family, with the exception of Alaska's Kodiak brown bears, which equal polar bears in size. (Overview page)
  3. ^ a b c Craig Boddington, illustrations by Ken Carlson (2004). Fair Chase in North America (illustrated ed.). Boone and Crockett Club. p. 45. ISBN 0940864479, 9780940864474. {{cite book}}: Check |isbn= value: invalid character (help)
  4. ^ American Heritage Dictionary of the English Language: Fourth Edition. 2000.
  5. ^ U.S. Fish and Wildlife Service (2006-11-17). "Endangered and Threatened Wildlife and Plants; Designating the Greater Yellowstone Ecosystem Population of Grizzly Bears as a Distinct Population Segment; Removing the Yellowstone Distinct Population Segment of Grizzly Bears From the Federal List of Endangered and Threatened Wildlife" (PDF). Federal Register / Vol. 70, No. 221. pp. 69854–69884. Retrieved August 1, 2006. {{cite web}}: Unknown parameter |dateformat= ignored (help)
  6. ^ a b Lisette P. Waits, Sandra L. Talbot, R.H. Ward and G. F. Shields (1998). "Mitochondrial DNA Phylogeography of the North American Brown Bear and Implications for Conservation". Conservation Biology. pp. 408–417. Retrieved August 1, 2006. {{cite web}}: Unknown parameter |dateformat= ignored (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  7. ^ "Wild find: Half grizzly, half polar bear: Hunter bags what expert 'never thought would happen' in wild". MSNBC.MSN.com. May 11, 2006. Retrieved 2006-05-14.
  8. ^ James Mallet (2008). "Hybridization, ecological races and the nature of species: empirical evidence for the ease of speciation" (PDF). Phil. Trans. R. Soc. B. 363 (363): 2971–2986. doi:10.1098/rstb.2008.0081.
  9. ^ Anthony D. Barnosky (2009). Island Press (ed.). Heatstroke: Nature in an Age of Global Warming. Washington, DC: Island Press/Shearwater Books. ISBN 1597261971.
  10. ^ a b c d Brown, Gary (1996). Great Bear Almanac. p. 340. ISBN 1558214747.
  11. ^ Ward Cameron. "Learn to Identify Black Bears and Grizzly (Brown) Bears". Mountainnature.com. Retrieved 2009-10-10.
  12. ^ Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc (1983), ISBN 978-0851122359
  13. ^ The Bear Facts - Types of bears in the Yukon, Yukon Education Student Network
  14. ^ "Kodiak Bear Fact Sheet". Alaska Department of Fish and Game, Division of Wildlife Conservation. 2008. Retrieved 2008-10-27.
  15. ^ Getty Images (2008-03-26). "Photo from Getty Images - News, photos, topics, and quotes". Daylife.com. Retrieved 2009-10-10.
  16. ^ Macdonald, David (1984). The Encyclopedia of Mammals: 1. London: Allen & Unwin. p. 446. ISBN 0-04-500028-x. {{cite book}}: Check |isbn= value: invalid character (help)
  17. ^ "300 kilos, 40mph ... brown bears colonise the Alps | World news". The Guardian. Retrieved 2009-10-10.
  18. ^ Bear Online Information System for Europe
  19. ^ "http://news.bbc.co.uk/2/hi/science/nature/4003325.stm". {{cite news}}: External link in |title= (help)
  20. ^ "Brown Bear Hunting in Russia". Russianbearhunt.com. Retrieved 2009-10-10.
  21. ^ Animal Diversity Web - Ursus arctos
  22. ^ "Brown Bear Reproduction". Shadowofthebear.com. Retrieved 2009-10-10.
  23. ^ Mating Strategies in Relation to Sexually Selected Infanticide in a Non-Social Carnivore: the Brown Bear
  24. ^ "Alaska Office of Economic Development". Dced.state.ak.us. Retrieved 2009-10-10.
  25. ^ "Yellowstone Grizzly Bears Eat 40,000 Moths a Day In August". Yellowstonepark.com. Retrieved 2009-10-10.
  26. ^ Betsy Downey. "Personal Encounter. Wolf-Grizzly interaction in Yellowstone National Park" (PDF). International Wolf Center.
  27. ^ Matthiessen, Peter (2001). Tigers In The Snow. North Point Press. ISBN 0865475962. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
  28. ^ Vratislav Mazak: Der Tiger. Nachdruck der 3. Auflage von 1983. Westarp Wissenschaften Hohenwarsleben, 2004 ISBN 3894327596
  29. ^ http://www.panthera.org/documents/Miquelle_Quigley_1996_Food_habits_of_Amur_tigers.pdf
  30. ^ Seryodkin, I. V., J. M. Goodrich, A. V. Kostyrya, B. O. Schleyer, E. N. Smirnov, L. L. Kerley, and D. G. Miquelle. 2005. Relationship between tigers, brown bears, and Himalayan black bears. Pages 156-163 in D. G. Miquelle, E. N. Smirnov, and J. M. Goodrich (eds.), Tigers of Sikhote-Alin Zapovednik: Ecology and Conservation. Vladivostok, Russia: PSP.
  31. ^ V.G Heptner & A.A. Sludskii (1992). Mammals of the Soviet Union, Volume II, Part 2. Leiden u.a.: Brill. ISBN 9004088768.
  32. ^ Notes[dead link]
  33. ^ adn.com | front: Polar bears, grizzlies increasingly gather on North Slope
  34. ^ "ABC News: Grizzlies Encroaching on Polar Bear Country". Abcnews.go.com. Retrieved 2009-10-10.
  35. ^ "http://www.bearsmart.com/managingBears/Relocation.html". {{cite web}}: External link in |title= (help)
  36. ^ Wilson, Don E., and DeeAnn M. Reeder, eds. "Ursus arctos californicus". Johns Hopkins University Press. Retrieved April 1, 2008. {{cite web}}: |author= has generic name (help); Unknown parameter |dateformat= ignored (help)CS1 maint: multiple names: authors list (link)
  37. ^ Bear Attacks: Their Causes and Avoidance, Stephen Herrero, revised edition, 2002.
  38. ^ a b WTom S. Smith, Ph.D. and Steven Herrero, Ph.D. "Ursus arctos californicus". Alaska Science Center - Biological Science Office. Retrieved April 12, 2008. {{cite web}}: Unknown parameter |dateformat= ignored (help)CS1 maint: multiple names: authors list (link)
  39. ^ "Why are grizzly bears more aggressive than our black bears?". Collegian.psu.edu. Retrieved 2009-10-10.
  40. ^ Two Bears in Fall Color. "How Dangerous are Black Bears". Bear.org. Retrieved 2009-10-10.
  41. ^ Smith, Herrero, DeBruyn, Wilde (2008). "Spray more effective than guns against bears: study". North American Bear Center. Retrieved 2009-03-28.{{cite web}}: CS1 maint: multiple names: authors list (link)
  42. ^ Smith, Tom S. "Brown Bear Projects at the Alaska Science Center". Alaska Science Center - Biological Science Office. Retrieved 2008-06-02.
  43. ^ "Alaska State Troopers Press Release of Monday, November 19, 2007" (Case Number: 07-96958). Alaska Department of Public Safety. 2007-11-19. Retrieved 2008-06-02.
  44. ^ Native American Animal Symbols - The Bear
  45. ^ Ad Council : Forest Fire Prevention - Smokey Bear (1944–Present)

External links

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