Bear - biology.

Bear - biology. I INTRODUCTION Bear, any of a group of mammals distinguished by a large, stocky body; powerful limbs; dense fur; and a short, stumpy tail. Bears live in North America, South America, Europe, and Asia, where they occupy a wide range of habitats, including mountain, forest, and Arctic wilderness. Over the last century bear populations have steadily declined as humans have overhunted bears and encroached on their habitat. Climate change may also threaten some bears, especially polar bears in the Arctic. Zoologists (scientists who study animals) classify eight species of bears: giant panda, spectacled bear, sun bear, sloth bear, Asiatic black bear, American black bear, brown bear, and polar bear. All of these species, with the exception of some populations of spectacled bears and sun bears, live north of the equator. Bears are not currently found in Africa, Australia, or Antarctica. All bears share a similar anatomy, but individual species vary in size, diet, and type of habitat. For example, polar bears live in frozen Arctic wilderness, where they feed primarily on seals, while sun bears live in Asian rain forests and dine on insects, fruits, nuts, and small animals. Reaching weights of 800 kg (1,760 lb), polar bears may grow 12 times larger than their smaller cousins the sun bears, which rarely exceed 66 kg (146 lb) in weight. Bears have long fascinated humans. Ancient cave art and more recent paintings and sculpture illustrate the fear as well as admiration with which people regard the awesome power and acute intelligence of bears. In fairy tales, bears are the symbolic image of brave deeds. In folk literature, the bear's habit of disappearing in winter months and emerging in spring evokes a theme of spiritual renewal, the replenishment of food, and the return of prosperity. In modern times, as the recreational use of parks and wilderness areas has grown dramatically, humans have experienced increased contact with bears. Bear attacks on humans are rare, however. American black bears killed fewer than 40 people during the 20th century. Grizzly bears, a type of brown bear, are more dangerous, but attacks on humans are still rare. In United States national parks that are home to grizzlies, injury rates from grizzly bears are about one person per 2 million visitors. Bears prefer to avoid humans, but when attacks do occur, they are usually the result of humans surprising these nervous, shy, and easily frightened animals. II PHYSICAL DESCRIPTION Bears are bulky animals with wide shoulders, a short back, short and thick legs, broad paws, and a short tail. They have an elongated head, rounded ears that stand straight up, small eyes, and a long snout. Bears hunt for food using an acute sense of hearing. Bears may have the best sense of smell of any mammal--some can detect odors up to a mile or more away. Bear eyesight is probably similar in acuity (sharpness) to human vision. Black bears, and likely other bears, have color vision, which helps them identify ripe fruits and nuts. Bears have 32 to 42 teeth, depending on the species, and these teeth reflect a varied diet of both plants and animals. Although all bears are members of the order Carnivora and are meat eaters, all but polar bears have become omnivorous--that is, they eat many types of foods, including lichens, roots, nuts, fruits, berries, seaweed, grasses, honey, grubs, caterpillars, and ants. Bear teeth are not as sharp or specialized for shearing meat as are those of some other carnivores, such as cats. For instance, canine teeth in most carnivores are generally large and pointed and are used for killing prey. In bears, however, these teeth are relatively small, and bears typically use them more to defend themselves or as tools. The molar teeth of bears are broad and flat, adapted to shredding and grinding plant food into small, easily digested pieces. Bears have four limbs that end in paws. Each paw has five long, sharp claws that are unretractile--unlike cats, bears are not able to retract their claws. Depending on the species, these claws may be used to climb trees, rip open termite nests and beehives, dig up roots, or catch prey. Bears walk differently than most carnivores, which tend to walk on their toes in a way that is adapted for speed. Like humans, bears have a plantigrade stance, walking with their weight on the soles of their hindfeet, with the heel touching the ground, while the toes of the forefeet are used more for balance. This distribution of weight toward the hindfeet gives bears a lumbering gait. Although bears are slower than most other carnivores, such as lions and wolves, a running bear can still reach speeds of 50 km/h (30 mph). Bears are far stronger than other carnivores, and their limbs are more flexible and agile. Bear fur is long and shaggy. Fur color varies among species, ranging from all white, blonde, or cream to black and white to all black or all brown. Fur color may also vary within a species. American black bears, for instance, may be black, brown, reddish-brown, or bluish-black. Several species, such as the sun bear and spectacled bear, have lighter-colored chest and facial markings. Males are larger than females in all bear species, but the difference between the sexes varies and is greatest in the largest species. Huge male polar bears may weigh twice as much as female polar bears, while smaller male and female sun bears are similar in weight. The life span of bears is not well known. The range seems to be about 25 to 40 years. Bears in the wild tend to die at a younger age than do their counterparts in zoos. III TYPES OF BEARS The bear family includes eight species, each showing remarkable variation in physical features and habits. Some scientists believe that bears and animals in the raccoon family share a common ancestor and are more closely related to each other than to other carnivores. Other scientists believe that bears are more closely related to walruses and sea lions. In the past, zoologists placed the giant panda in the raccoon family, but recent analysis of the giant panda's genetic makeup and fossil evidence have convincingly established the giant panda as a member of the bear family. A Giant Panda Possibly the world's best-known wild animal, the giant panda has a round body, a bullet-like head with small ears, and a short, stumpy tail. Its shaggy coat is white with a black patch around each eye and a ring of black around the shoulders, front legs, and chest. The giant panda can reach a length of 1.5 m (5 ft) and weigh 100 kg (220 lb). The giant panda has the smallest range and smallest population of all the bears. Only about 1,600 individuals live in bamboo forests in the mountains of south-central China. Bamboo makes up about 99 percent of the giant panda's diet, and the bear spends 12 to 14 hours each day eating up to 18 kg (40 lb) of bamboo leaves and stems or 39 kg (85 lb) of shoots. The giant panda brings food to its mouth with its front paws, using a long wrist bone that works like a thumb to grasp bamboo stems. Despite their cute, cuddly appearance, giant pandas can be provoked to aggressive defensive behavior. With such a small population, a narrow habitat range, and a highly specialized diet, giant pandas are widely considered in great danger of extinction. They are classified as endangered species on both the United States Fish and Wildlife Service Endangered Species List and the Red List of Threatened Species compiled by the World Conservation Union (IUCN), a nongovernmental organization that compiles global information on endangered species. These classifications offer these animals protection and provide opportunities for conservation management, including strictly enforced protection from hunting in their habitats. The Chinese government, as well as many private organizations and zoos around the world, support conservation activities that encourage local people to protect the giant panda and its habitat. A number of programs sponsored by zoos or other breeding centers have attempted to breed giant pandas in captivity, although most of these programs have proved unsuccessful. Among the difficulties faced by captive breeders has been the problem of encouraging a female giant panda to mate with a selected male during the two to three days of the year when she is most fertile, a period known as estrus. B Spectacled Bear Creamy-white rings surrounding the eyes give the spectacled bear its name. Its shaggy coat of black or dark brown is marked by white or yellow coloring on the muzzle and in a roughly shaped circle on the chest. Also known as the Andean bear, it is the only bear native to South America, where it lives on the forested slopes of the Andes Mountains from western Venezuela and Colombia south to Ecuador, Peru, and Bolivia. Spectacled bears grow to a length of about 1.8 m (about 6 ft) and weigh 62 to 154 kg (137 to 340 lb); the males are much larger than the females. Spectacled bears eat diverse foods, including small mammals and birds, grasses, fruits and berries, and parts of bromeliads (plants such as pineapple), orchid bulbs, and palm nuts. These bears build tree nests for sleeping during the day from which they can pluck fruit from nearby branches. The IUCN Red List of Threatened Animals lists the spectacled bear as vulnerable. This status means that the bear faces a high risk of extinction in the near future, due to human encroachment on its habitat, hunting, and poaching to extract bear parts for use in folk medicine. Although the South American countries that are home to these bears have laws protecting the animal, enforcement of these laws is usually weak. C Sun Bear Named for the golden-colored crescent that adorns its chest, the sun bear is also known as the Malayan sun bear and the dog bear. A rarely seen resident of Southeast Asian rain forests, sun bears range from Burma south to the islands of Sumatra and Borneo. Sun bears grow up to 1.5 m (5 ft) long and weigh 27 to 66 kg (60 to 146 lb), making them the smallest of bears. The coat is short, sleek, and black, with light brown feet and white or orange-yellow fur on the muzzle and chest. The sun bear uses its extremely long tongue to feed on insects and honey in tree cavities. Its diet also includes fruits and vegetation, birds, and other small animals. The sun bear is listed as vulnerable on the IUCN Red List of Threatened Animals. Scientists know little about the sun bear's natural history, population numbers, and distribution. However, the destruction of rain forests in Southeast Asia for timber harvesting and to make room for new farmland and houses, makes the future of the sun bear seem bleak. Hunting in Thailand may have reduced its numbers in some parts of that country by 50 percent in 20 years. D Sloth Bear So called for its close resemblance to the sloths of Central and South America, the sloth bear is also occasionally referred to as the honey bear. Sloth bears inhabit forests and tall grasslands in India, Nepal, Sri Lanka, and Bhutan. Their long, shaggy coat is commonly black, but it may be red or reddish-brown, turning a lighter color on the muzzle and chest. The sloth bear grows to about 1.8 m (about 6 ft) and weighs 54 to 140 kg (119 to 310 lb). Other carnivores that share their habitat, including tigers and leopards, prey on these medium-sized bears. This may be why sloth bear mothers carry their one or two cubs on their backs--so that they can protect their young while making a quick escape from predators. Sloth bears eat a variety of fruits, honeycombs, and insects, but with their hairless lips, flexible snout, and gapped front upper teeth these bears are particularly adapted for feeding on ants and termites. They use their long claws to open ant and termite nests. Their lips and snout then form a central opening that acts as a suction tube, which they use to suck up the insects, making sucking and blowing noises that sound like a jackhammer. Listed as vulnerable by the IUCN Red List of Threatened Animals, sloth bears are regularly killed in order to obtain and sell bear parts, such as gallbladders, that are used in folk medicine. Laws to prevent killing of sloth bears and the export of their parts are poorly enforced, resulting in a significant harvest of the species for commercial purposes. E Asiatic Black Bear The Asiatic black bear is also known as the moon bear for the distinctive white, crescent-shaped patch on its chest. Other names for this bear include the Himalayan bear, the Tibetan bear, and the Japanese black bear. This bear lives in temperate mountain forests in widely separated areas in Asia, ranging from Afghanistan to Vietnam and northeast China, as well as in southeast Russia, Taiwan, and on the Japanese islands of Honsh? and Shikoku. Its coat is usually black, but it may be brown, with white coloration on the chin. The Asiatic black bear can reach 1.6 m (5.25 ft) in length and can weigh up to 200 kg (440 lb). Asiatic black bears climb trees to collect the fruits and nuts that make up most of their diet; they also gather these morsels on the forest floor. Many Asiatic black bears migrate seasonally--in warmer months they move to higher elevations and in colder months they return to lower elevations. Most Asiatic black bears (except those in the southern parts of their range) fatten up in the fall and then retreat to a den during the winter. Despite its protection by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which regulates and restricts the trade of threatened plants and animals, the Asiatic black bear is highly prized on the black market. It is a popular circus animal, and it remains a favored species for gall bladders and other bear parts used in traditional medicine. The IUCN Red List of Threatened Animals rates this bear as vulnerable. Without strict law enforcement preventing trade on international markets, this bear is at high risk of extinction in the near future. F American Black Bear American black bears are native to North America, ranging from Alaska and Canada to mountains in northern Mexico. They are secretive, forest-living creatures that have learned to adapt to human-populated areas. They have even been known to winter in suburban back yards without the human residents' knowledge. After centuries of hunting and habitat destruction following the European colonization of North America, black bear numbers are now stable or increasing, even in the eastern United States where human population is dense. The National Biological Service of the United States Department of the Interior estimates that there are 650,000 to 700,000 black bears in North America. The smallest of North America's three bear species, the American black bear can grow to 1.8 m (6 ft) in length and weighs from 40 to 300 kg (90 to 660 lb), with males larger than females. American black bears usually have glossy black coats, although bears with red- and honey-colored coats are common. The Kermode bear, a subspecies of black bear that lives in the rain forests of British Columbia, Canada, sports white fur. The black bear's mostly vegetarian diet includes grass and green plants, berries and other fruits, and walnuts and acorns, although black bears sometimes eat deer fawns and moose calves. In preparation for fasting during the winter months, a black bear gains up to 1.5 kg (3 lb) per day for two months in the fall. The American black bear is a mostly thriving species in the United States; only isolated black bear populations in Louisiana, Texas, and Mississippi are listed as threatened by the U.S. Fish and Wildlife Service. Some experts believe that Florida's small black bear population should have the protection offered by a threatened status. All 32 states with black bear populations have established carefully managed sport-hunting programs. Hunters kill more than 40,000 black bears each year. CITES prohibits the trade in American black bears and bear parts unless a special permit is obtained, certifying that the trade will not harm the species, that the specimen was obtained legally, and for living specimens, that adequate measures were taken to assure safe transport. G Brown Bear The brown bear is distinguished from other bear species by the presence of a prominent shoulder hump and an upturned snout. The brown bear's vast range includes parts of Europe, Asia, and North America, where the bears inhabit a variety of habitats, including tundra, dense forests, and deserts. Within these regions, populations are mostly small, isolated, and restricted to remote areas. Coat color in brown bears ranges from a creamy white through various shades of brown to almost jet-black. In certain subspecies of brown bears, such as the grizzly bear found in inland areas, the hairs on the back may be white-tipped, giving the outer coat a grayish, or grizzled, appearance. Brown bears, along with polar bears, are the largest of the bear species. In general, brown bears range in weight from less than 90 kg (200 lb) for small females to more than 800 kg (1,760 lb) for the largest males. Brown bear populations differ significantly in size, depending largely on available diet. Coastal populations that feed on abundant, fatty salmon in Alaska, for instance, may be three times larger than inland bears, such as grizzlies, which subsist on plant parts, insects, and some meat they steal from wolves or catch themselves. As a result of their fatty fish diet, the Alaskan brown bear, a subspecies that ranges throughout coastal Alaska and western Canada, and the Kodiak bear, a subspecies found on three Alaskan islands that make up the Kodiak archipelago, are the largest brown bears. The Alaskan brown bear may weigh up to 800 kg (1,760 lb) and reach 2.3 m (7.5 ft) in length. The Kodiak bear can grow to 770 kg (1,700 lb) and reach the towering height of 3 m (10 ft). The brown bear population in Alaska is estimated at 32,000. Elsewhere in North America, brown bears may number fewer than 1,200 individuals, and these animals are listed as threatened by the U.S. Fish and Wildlife Service. In 2007 the population of grizzly bears in Yellowstone National Park was removed from the list of threatened and endangered species, although grizzlies in other areas are still listed as threatened. The IUCN Red List of Threatened Animals does not list the brown bear, although populations in Western Europe have been greatly reduced by habitat destruction and hunting. Fewer than 10 bears remain in the Pyrenees Mountains between Spain and France, and a similar number survive in the Italian Alps. About 5,000 to 6,000 brown bears live in Eastern Europe, and more than 120,000 live in Russia. H Polar Bear The polar bear inhabits the polar regions of the Northern Hemisphere, where its white fur blends perfectly with its ice- and snow-covered Arctic habitat. Although primarily found along coasts and ice floes, polar bears may winter in dens up to 48 km (30 mi) inland. Polar bears are one of the largest bear species and can grow to a length of 2 m (7 ft) and weigh up to 800 kg (1,760 lb). Excellent long-distance swimmers, polar bears use their large front feet as paddles and trailing back feet as rudders. With little vegetation in their frigid environment, polar bears are the most carnivorous of bears, eating primarily seals and sometimes young walruses. They prefer to hunt seals on land or ice but may stalk them from under water. During the summer months when ice floes melt, polar bears are unable to hunt seals and may wander far inland seeking berries, bird eggs, and other foods. Polar bears are listed as vulnerable on the IUCN Red List of Threatened Species. The United States is considering adding the polar bear to its list of threatened and endangered species under the Endangered Species Act. From 22,000 to 25,000 polar bears make up 19 population groups that live in five Arctic areas of Greenland, Norway, Russia, Canada, and the United States. Loss of sea ice as a result of global warming may pose the greatest threat to polar bear populations--the bears use the ice for hunting seals and for resting. As much as two-thirds of the world's population of polar bears may disappear within 50 years as sea ice dwindles. Concentration of pollutants in the Arctic food chain can also affect health and reproduction in polar bears. In addition, polar bear populations remain at risk from ongoing oil and gas exploration and development in the Arctic region. Hunting policies that target adult male polar bears may reduce reproduction success in some regions of Canada. IV BEAR BEHAVIOR Bears mostly live alone, except for mothers and their cubs, and males and females during mating season. Bears form temporary groups only in exceptional circumstances, when food is plentiful in a small area. Alaskan brown bears may collect in the same area to feed on salmon during the annual salmon runs, when salmon swim up river to reach their spawning grounds. Recent evidence also suggests that giant pandas may form small social groups, perhaps because bamboo is more concentrated than the patchy food resources of other bear species. Other bears may live alone but exist in a social network. A male and female may live in an overlapping home range--although they tolerate each other, each defends its range from other bears of the same sex. Male young usually leave their mothers to live in other areas, but female young often live in a range that overlaps with that of their mother. The key to a bear's survival is finding enough food to satisfy the energy demands of its large size. Bears travel over huge territories in search of food, and they remember the details of the landscape they cover. They use their excellent memories to return to locations where they have had success finding food in past years or seasons. Most bears are able to climb trees to chase prey or gain access to additional plant vegetation. The exceptions are polar bears and large adult brown bears--their heavy weight makes it difficult for them to climb trees. Little is known about communication among bears. Vocalizations and movements of the mouth and ears appear to be communication methods used by most species. Scent marking for communication is done by urine or by rubbing trees. When they need to act threatening or fight, bears tend to stand up on their hind legs, perhaps to appear larger to their rivals. They use their clawed forepaws to slash at their opponents. Bears that live in regions with cold winters spend the coldest part of the year asleep in sheltered dens, including brown bears, American and Asiatic black bears, and female polar bears. Pregnant females give birth in the winter in the protected surroundings of these dens. After fattening up during the summer and fall when food is abundant, the bears go into this winter dormancy to conserve energy during the part of the year when food is scarce. Winter sleep differs from hibernation in that a bear is easily aroused from sleep. In addition, a bear's body temperature drops only a few degrees--an American black bear with an active body temperature of around 38°C (100°F) will undergo a moderate drop in body temperature to about 34°C (93°F). In contrast, a true hibernator undergoes more extensive changes in bodily functions. For instance, the body temperature of the Arctic ground squirrel drops from 38°C (100°F) to as low as -3°C (27°F). V REPRODUCTION Reproduction is seasonal for most bears. For bears living in temperate zones with four seasons, mating occurs in the spring after bears emerge from winter sleep. Bears that live in tropical regions, such as sloth bears, mate during the dry season. A male and female typically stay together for one to two weeks during mating season, mating many times before going their separate ways. After mating, the gestation, or pregnancy, period generally ranges from seven to nine months, depending on the species. The actual development period of the unborn young is not as long as the gestation period suggests because the embryo passes through a period of delayed implantation. In this process, the newly forming embryo halts development and becomes inactive for as long as six months. The embryo then resumes its activity and becomes implanted in the wall of the female's uterus, where its development proceeds rapidly. In the American black bear an embryo formed from a June mating may not become implanted until sometime in November. This delayed implantation enables birth to coincide with a bear's winter sleep. The vulnerable newborns, born within the safety of dens, receive additional warmth and protection as they share close quarters with their mother. Bears usually produce litters of one to three cubs. Like most carnivores, bear babies are smaller at birth than the young of most other mammals, sometimes weighing 1 percent or less of their mother's body weight. A newborn giant panda cub weighs around 113 g (4 oz). All bear young are born blind, toothless, mostly hairless, and completely helpless. They grow quickly, nourished by milk from their mother that is high in fat. By about three months of age, cubs leave the den to forage for food with their mother. Cubs are weaned at about six months of age but stay with their mother for two to three or more years while they learn from her what to eat and where to find food. Mothers also try to protect their cubs from adult males, which sometimes kill cubs. This behavior on the part of males may be a strategy to increase breeding opportunities, as females without cubs will be more readily available to mate. Females become sexually mature at four to seven years of age and may then produce young every two to five years. In general, the age at which a bear first reproduces comes earlier when food is abundant and later when food is limited. VI EVOLUTION Bears are the youngest of the carnivore families, having arisen from doglike ancestors during the Eocene Epoch, around 55 million to 38 million years ago. The earliest bears had the characteristics of both dogs and bears, with heavy-set features and blunter teeth than those of true dogs. Modern bears appeared in Eurasia around 5 million years ago during the late Miocene Epoch. These bears were relatively small animals, but some types eventually grew quite large. They diversified and spread through Europe, Asia, and North America, eventually reaching South America. Fossils indicate that bears once lived in Africa, with one large primitive species found as far south as present-day South Africa. Among the extinct bears was the largest land-living mammalian carnivore. The giant short-faced bear was almost twice as big as today's brown bear. Unlike modern bears, it was lightly built, with long legs and feet that enabled it to run fast. It was likely a powerful hunter capable of killing large prey. However, recent research suggests it may also have used its size and strength to chase other predators away from their kills. The giant short-faced bear lived in North America during the Pleistocene Epoch, from 1.6 million to 10,000 years ago. The earliest people to reach North America, perhaps as early as 15,000 years ago, must have found this animal truly frightening. The short-faced bear spread into South America. Scientists believe the spectacled bear is a smaller relative of this extinct bear. Perhaps the most famous extinct species is the great cave bear, which lived in Europe around the Middle and Late Pleistocene and became extinct around 10,000 years ago. Its bones have been found in caves from Spain to the Caucasus. The largest deposit of remains is that of the Drachenhohle caves in Austria, which contain the remains of about 30,000 cave bears. Many of the remains are those of animals that over the centuries died in the caves during their winter dormancy, probably as a result of illness, lack of food, or old age. Distinguished by a massive skull and a domed forehead, this bear was as large as the modern Alaskan brown bear. Its teeth indicate that it ate an almost exclusively vegetarian diet. Cave drawings created by Ice Age humans show that they occasionally hunted cave bears. For several thousand years the modern brown bear and the cave bear co-existed, but the cave bear became extinct around 10,000 years ago. The modern brown bear first appeared in Asia during the Middle Pleistocene Epoch and then spread to North America and Europe, even reaching northern Africa. A population of brown bears that lived along the coast became specialized for hunting seals, eventually evolving into the polar bear around 700,000 years ago. The American black bear dates to before the Late Pleistocene, and unlike today's black bears, these prehistoric black bears grew as large as modern grizzlies. The first giant pandas appeared in Europe in the late Miocene and were found in eastern Asia during the Pleistocene Epoch. VII BEARS AND HUMANS Humans have hunted bears since prehistoric times, using bear flesh for food and bear fur to make clothing. Early humans may have learned which plants were edible by watching cave bears forage for food. More recently, humans have contributed to the decline of bear populations worldwide, mainly by encroaching on bear habitats through farming, settlement, logging, and mining. Despite laws protecting bears, people continue to hunt bears for sport, for food, to protect crops and livestock, and for certain bear parts used in a variety of traditional medicines. Six of the existing eight species of bears are listed as endangered or vulnerable according to the World Conservation Union (IUCN) Red List issued in 2007. Only the brown bear and the American black bear are not considered threatened or endangered within their natural ranges. As humans encroach on bear habitats, the opportunity for humans and bears to interact is becoming more and more common. In general, bears prefer to avoid humans, but often they have no choice but to enter suburbs and other populated areas in search of food. Humans may also stumble upon bears that are foraging for food in wilderness areas. Bear attacks are extremely rare, and most human encounters with a bear that result in the bear responding aggressively are the result of humans surprising bears and causing them to feel threatened. Bears can be attracted to food or food waste left by people, although high-calorie human food is unhealthy for bears to eat. Polar bears sometimes forage at open garbage dumps in Arctic areas, risking encounters with humans. Bears in wilderness parks where people camp may seek out garbage or food kept at campsites. Special food and garbage storage containers have been designed to block access to bears. Bears that enter camping areas to find food are a danger to people and must either be relocated or destroyed. To avoid dangerous encounters with bears, the Minnesota-based American Bear Association, a nonprofit organization, recommends that people who come into contact with a bear not run away. A bear can easily outrun a human. Instead, the association advises people to stay calm and avoid direct eye contact with the bear. According to the association, people should talk to the bear in a soothing voice, try to appear larger by raising their arms over their head, and slowly back away from the bear and retreat from the area, making a wide detour around the bear. Because of their extremely acute sense of smell, bears can often be deterred from attacking by irritating chemicals in bear-spray products. Scientific classification: The eight living species of bears make up the family Ursidae in the order Carnivora, class Mammalia. The giant panda is classified as Ailuropoda melanoleuca. The spectacled bear is classified as Tremarctos ornatus. The sun bear is Helarctos malayanus (also classified as Ursus malayanus), and the sloth bear is Melursus ursinus. The Asiatic black bear is Ursus thibetanus. The American black bear is Ursus americanus and the subspecies Kermode bear is Ursus americanus kermodei. The brown bear is Ursus arctos, the subspecies grizzly and Alaskan brown bear are both classified as Ursus arctos horribilis, and the Kodiak bear is Ursus arctos middendorffi. The polar bear is classified as Ursus maritimus. Contributed By: John Seidensticker Susan Lumpkin Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.