Bears

(Ursidae)

Class Mammalia

Order Carnivora

Suborder Fissipedia

Family Ursidae

Thumbnail description
Medium to large, stocky mammals with fur that may be black, brown, reddish, or white

Size
Adults average 4–5 ft (1.2–1.5 m) and 60–150 lbs (27–70 kg) in body length for sun bears to 8–9 ft (2.4–2.7 m) and 900–1,300 lbs (400–590 kg) for polar bears

Number of genera, species
3–6 genera; 8 (or more) species

Habitat
Wide ranging, including forests, rainforests, tundra, deserts, and swamps

Conservation status
Endangered: 1 species; Vulnerable: 3 species; Lower Risk/Conservation Dependent: 1 species; Data Deficient: 1 species

Distribution
On every continent except Africa and Antarctica, but mainly in the Northern Hemisphere

Evolution and systematics

Although this family has a small number of genera and species, it still has a good share of controversy when it comes to classification. For example, some systematists over the years have placed the giant panda in a subfamily of Ursidae, as it is in this chapter, or in its own family, called Ailuropodidae. The Malayan sun bear, sloth bear, and polar bear are often grouped under the Ursus genus, but sometimes fall under the genera Helarctos, Melursus, and Thalarctos, respectively. Subspecies of the brown bear (U. arctos) are often listed as separate species, including the Alaskan brown bear (U. middendorffi) and the grizzly bear (U. horribilis). In addition, the red panda (Ailurus fulgens) was once listed with the ursids, but is now considered a to be a member of its own family, the Ailuridae, or a sub-family of the Procyonidae, which includes the raccoons.

This chapter uses the following classification:

• giant panda, Ailuropoda melanoleuca
• Malayan sun bear, Helarctos malayanus
• sloth bear, Melursus ursinus
• spectacled bear, Tremarctos ornatus
• American black bear, Ursus americanus
• brown bear, U. arctos
• polar bear, U. maritimus
• Asiatic black bear, U. thibetanus

The family Ursidae is believed to have originated in Asia, and is closely related to the canids (dogs and relatives), procyonids (raccoons and relatives), and ailurids (lesser panda). The giant panda is considered to be the most primitive of the bears. Various evolutionary studies have attempted to determine the relationships of the other bears. Fossil studies seem to indicate that the spectacled bear, which is in the subfamily Tremarctinae, diverged from the remaining bears, which are in the subfamily Ursinae. The fossil record also points to a very close relationship between the Asiatic black and American black bears, and places brown and polar bears close to

them evolutionarily. Other studies using mitochondrial DNA and cytochrone-b sequence data have provided clarification, and sometimes challenged, previous conclusions. For example, mtDNA data have indicated that polar bears and spectacled bears are very closely related, and diverged from the ursinids about 2 million years ago. Cytochrome-b data appear to show that the sun bear and American black bear are sister taxa, and are somewhat separated from the Asiatic black bear.

Physical characteristics

Bears are medium to large, powerful mammals with rather short tails and plantigrade feet on stocky limbs. Many bears are dark brown to black, but the fur color is often variable within the species and sometimes even among siblings. Among the American black bear, for instance, black, brown, reddish, and even whitish individuals exist. Some species have distinctive white patches or lines on the face, throat, and/or chest. An example is the spectacled bear, which has whitish rings around its eyes. The polar bear is the only species that consists of all white-furred individuals, although the skin is black to make the best use of the heat from the arctic sun, and the individual outer (or guard) hairs are actually clear rather than white. Some species, such as the brown bear, have longer hair on the shoulders that forms a mane. A few, like the sloth bear, have long fur over much of their bodies.

Their heads are rather large, particularly in some species like the panda, and they have small, forward-facing eyes, and noticeable but usually modest round ears. Their teeth include premolars and molars designed for crushing, and long canines, which together assist their omnivorous diet. The giant panda and spectacled bear have flattened molars suited to their strongly herbivorous diets. The sloth bear, which is particularly fond of termites, has no incisors in its upper jaw. The gap, combined with protrusible and naked lips, allows the bear to suck up the insects. Sun bears have especially long tongues to assist them in attaining honey, a frequent item in their diet.

Bear claws, which are non-retractile, differ in length in separate species. In the brown bear, for example, the light-colored claws stand out from the typically brown fur, and range from 2–4 in (5–10 cm) long. The Asiatic black bear, on the other hand, has comparatively short claws, typically measuring less than 2 in (4–5 cm) in length.

In overall size, bears have a fairly wide range. In all species, males are larger than females. The smallest ursid is the Malayan sun bear, with a body length of 4–5 ft (1.2–1.5 m), and a typical male weight of 60–150 lb (27–70 kg). Polar and brown bears are at the opposite end of the spectrum, with male polar bears averaging 8–9 ft (2.4–2.7 m) in body length and 900–1,300 lb (400–590 kg), and male brown bears 5–8 ft (1.5–2.4 m) and about 350–850 lb (160–385 kg).

Distribution

Bears have a wide distribution in the Northern Hemisphere. Here, the most widely distributed species include the polar bears, which inhabit the circumpolar ice pack; the brown bears, which live throughout northern North American and north to north-central Eurasia; and the American black bear, which stretches from northern Mexico well into Canada. Both the sun bear and sloth bear reside in Southeast Asia. The range of the Asiatic black bear is somewhat larger, extending from Afghanistan to southeastern Russia. The giant panda has the smallest range of all bears, with six small populations known from the Tibetan plateau in southwestern China. The spectacled bear, the only ursid that inhabits in the Southern Hemisphere, lives around the Andes in South America, including sites in Bolivia, Colombia, Ecuador, Peru, and Venezuela.

Habitat

Bears' habitats vary from species to species. The polar bear thrives on the arctic ice pack, a sharp contrast to the tropical rainforests of southeast Asia, where the Malayan sun bear resides. The American black bear's habitat spreads from the woods in western U.S. mountains to wetlands in southeastern

states, and to the northern tundra in Canada. In contrast, the shaggy-looking sloth bear opts for grasslands and dry forests from lowlands in India to the foothills of the Himalayas.

The brown bear, also known in parts of North America as the grizzly or kodiak, ranges from thickly forested areas into grasslands and tundra in the Northern Hemisphere, while the spectacled bear prefers lush mountain forests in South America. The giant panda lives in the bamboo forests of China, and the Asiatic black bear in primarily moist forests throughout southern Asia.

Home ranges for bears also vary. Pandas keep to about 2–3 mi², but brown bears are known to range over 800–1,000 mi² if the habitat is poor and food is scarce.

Behavior

Little is known about the behavior in the wild of half of the ursid species, mostly due to their remote geographical distribution. These include the spectacled bear, Asiatic black

bear, sun bear, and sloth bear. In general, however, bears overall are solitary animals except during mating season or in mother-cub groupings. Occasionally among brown bears, siblings will stay near one another for a year or two after they leave their mother. Although additional research is needed for substantiation, some reports indicate that sloth bears may form social units, and that male sun bears may remain with the mother after she gives birth.

Bears generally maintain home ranges, with the males' ranges frequently overlapping with those of the females. Black bears mark their territories with scent markings or long scratches clawed into trees. Unusually, male panda bears sometimes do their scent marking while standing on their hands. In black bears and several other species, the ranges of male bears may also overlap, but since the ranges are often very large and bears rarely see one another, the overlaps present little opportunity for territorial conflicts. Even when bears come together at one feeding site, such as brown or black bears at a salmon stream, individual bears maintain their personal space and share the resource. When bears approach one another too closely, temporary dominance hierarchies may form, with the largest males mounting short-lived aggressive displays, including growls, and occasional charges to maintain a small feeding territory. During breeding season, males generally compete for females, but the male-female bonds typically only last one or two weeks.

With their large, plantigrade feet and stout limbs, bears are often pictured as lumbering animals that always move slowly and deliberately. They can, however, move very quickly when necessary. Black bears, for example, can run at speeds of 30 mph (50 kph), and polar bears are fast enough to catch caribou on the Arctic tundra. Even the somewhat awkward-moving sloth bear can outrun a human over short distances. Most bears are also accomplished tree climbers. The sun bear has perfected climbing, quickly scaling trees in search of honey and other food items, and even fashioning resting/feeding platforms out of broken branches high up in the trees. Polar bears and adult brown bears (with the exception of some populations in Europe) do not climb, but both are good swimmers. Other bears, like the Asiatic black bear, can also swim. With their large and slightly webbed front feet, polar bears are particularly adept swimmers and divers, and reportedly are able to swim across open-water expanses of up to 100 mi (65 km).

Ursids tend to be crepuscular (mainly active at dawn and dusk) or nocturnal animals, although some extend their active periods into the daytime. Polar bears are an example. While they are most active at night and at dawn, they are frequently seen hunting during the day.

Although ursids do not technically hibernate, many cooler-climate bears do enter winter dormancy, during which the respiratory and heart rates drop, but the body temperature dips only slightly. In the black bear, for instance, their body temperature drops from about 100°F (38°C) to 88–93°F (31–34°C). The Asiatic black bear is an exception: Its body temperature declines precipitously to just 37–45°F (3–7°C). It is during the winter dormancy that female ursids give birth. As she sleeps, the young suckle and grow. Among the cooler-climate species, both males and females become dormant, except in the polar bears, where only pregnant females enter winter sleep. During the winter, bears are capable of awakening, and occasionally leave their winter dens, which may be burrows, hollow logs, or tunnels in the snow and ice. Warm-climate bears, including sun, sloth, and spectacled bears, do not enter winter sleep. Although most brown bears and Asiatic black bears "hibernate," those from warmer climates frequently skip winter dormancy and remain active all year.

Feeding ecology and diet

Bears are omnivores, often eating whatever is available. The polar bear tends heavily toward a carnivorous diet, existing primarily on ringed seals (Phoca hispida), although it will eat berries and vegetation in the summer. Hunting is accomplished either by ambush or active stalking. In the former, the polar bear will simply wait at an ice hole for a seal to surface, then overpower it with one whack of its mighty paw. It reverts to stalking either on land or in the water if it happens to see a seal on the ice or another animal, such as an elk, in the open. With the polar bear's cryptic coloration, it can approach closely enough on land to give chase and sometimes overtake the animal.

Other ursids tend to prefer a greater amount of vegetation than the polar bear, eating fruits, tender stems, and roots most of the time, and supplementing the diet with insects, fish, an occasional small mammal, or carrion. The larger bears, like the brown bear, will sporadically hunt moose, or elk (Alces alces), and other ungulates. The giant panda, on the other hand, is almost exclusively an herbivore, eating little but bamboo leaves, stems and shoots. Sloth bears are unusual in their strong reliance on termites for food, although other bears also eat termites to some extent. Sloth bears, along with the sun bear in particular, are also fond of honey. In both cases, the bears use their claws to rip open termite and bees nests, and get at the reward.

Reproductive biology

Bears' mating systems vary by species; some, such as the spectacled bear, are monogamous. Others, such as the polar bear, are polygamous. Most bears mate in the spring or summer, but the fertilized eggs do not implant in the uterus and begin developing until fall. After this so-called delayed implantation, the eggs begin to develop and the females give birth in the winter. Some species, including the sloth bear, apparently mate year-round in especially warm climates, but due to delayed implantation, all give birth in the winter. Sun bears appear to have delayed implantation, but individuals in zoos have given birth at different times of the year.

Cubs are born small, naked and blind, having developed in the womb for only two to three months. Birth weight ranges from about 11 oz (325 g) in sun bears to 21 oz (600 g) in brown and polar bears. In most cases, females give birth from one to five cubs, although two is the most common litter size among ursids. Panda mothers generally rear only one cub, regardless of the litter size, and the others die. Among cooler-climate bears, the young are born while the mother is in winter dormancy. In warmer-climate species, such as the sun bear, the mother chooses a concealed site, perhaps under branches or thick vegetation, to make a nest for the cubs. Cubs are generally weaned within the first two to five months (pandas wean at about nine months), but remain with the family unit for two to four years, during which the cubs learn to find their own food and hunt while under the protective eye of their mother.

Sexual maturity generally occurs from four to seven years old, but the timing varies among species.

Conservation status

Only one ursid, the panda bear, has been listed as Endangered by the IUCN. Habitat destruction is a major reason for this species' decline. A recent study indicated that not only human population magnitude, but the increasing number of households as family units decrease in size, have contributed to intensifying habitat destruction, particularly for this bear. As the number of households have risen, deforestation and fragmentation of panda habitat have accelerated. Estimates place the total number of pandas in the wild at below 1,000.

Other bears have also experienced decreased suitable habitat and habitat fragmentation. The brown bear, for instance, is now found in only 2% of its former range within the continental United States. The lessened range is blamed in part on habitat destruction and fragmentation. In addition, individual populations of various species have experienced declines, even if the overall species numbers are relatively high. The American black bear is an example. Several subspecies, including Ursus americanus floridanus, are considered threatened locally. To counteract the declines, various hunting bans or regulations, habitat preservation programs, and educational efforts are under way worldwide.

The sloth bear, spectacled bear, and Asiatic black bear are listed as Vulnerable; the polar bear is Lower Risk/Conservation Dependent; and the Malayan sun bear is listed as Data Deficient by the IUCN.

Significance to humans

Various bears are hunted for meat, fur, and trophy mounts. In addition, body parts, such as the gall bladder of sun and American black bears, are also harvested for medicinal purposes, particularly in China. Bears have also become important as attractions at zoos.

While many bears are assumed to be dangerous to humans, bear attacks are few and fatalities are rare.

Species accounts

List of Species

American black bear

Ursus americanus

subfamily

Ursinae

taxonomy

Ursus americanus Pallas, 1780, type locality not given but assumed to be eastern North America. Up to 18 subspecies.

other common names

English: North American black bear, cinnamon bear, kermode bear, glacier bear; French: L'ours noir; German: Amerikanischer Schwarzbär; Spanish: Oso negro, oso varibal, oso negro americano.

physical characteristics

A relatively short-haired bear with curved claws; rather short tail; conspicuous, but not overly large ears; and fairly long, often tawny snout. Somewhat similar to the brown bear, but the American black bear's shoulders are lower than its rump when walking. Fur coloration can vary from brown to black, sometimes reddish, bluish black, and occasionally white, with geographically distinct subspecies typically tending toward one color pelage, although color can vary even among brothers and sisters. They often have a bit of white fur on the chest. Head and body length runs from about 5–6 ft (1.5–1.8 m), and shoulder height at about 2–3 ft (60–90 cm). Standing, a typical adult reaches about 5 ft (1.5 m). Weight differs among the sexes, with the males averaging 250–350 lb (110–160 kg), almost

twice the female's average weight of about 150–175 lb (70–80 kg). The largest males can reach up to 800–900 lb (360–400 kg) when they are at their heaviest just before hibernation, although these extreme weights are rare.

distribution

Northernmost Mexico, all but north-central Canada, and about half of the United States, especially Alaska and the western and eastern states, and the upper Great Lakes region.

habitat

Commonly woods with thick undergrowth, but also wetland areas, meadows, tundra particularly in Labrador, and sometimes disturbed sites near human activity.

behavior

American black bears are commonly crepuscular and spend most of the day and night resting in a clump of leaves on the ground, although they may shift this schedule and become active during the day. Despite their typically lumbering gait, they can break into short 30 mph (48 kph) runs if necessary. They are also good swimmers and expert tree climbers, using their front claws to scale a trunk in very short order.

American black bears spend much of the winter dormant, but scientists do not consider them true hibernators, because they frequently awaken from deep sleep to leave their winter dens for short periods. Their dens may be caves; hollow, standing or fallen trees; or burrows.

American black bears are typically solitary, except for females with cubs, and maintain feeding territories of 8–15 mi² (20–40 km²) throughout much of the year. At sites where food is abundant, such as garbage dumps, however, several adult males and females may share a small area. Males and females pair up for breeding for only a few days at most.

feeding ecology and diet

These omnivores eat almost anything, and are most frequently seen by humans scavenging for leftovers at campsites and garbage dumps. In the wild, they tend toward a vegetarian diet, eating everything from berries and nuts to grasses and roots, but will also dine on honey, salmon, ants and other insects, rodents, an occasional young ungulate, livestock, and carrion when the opportunities arise.

reproductive biology

Polygynous. Mating occurs from late spring to early summer, but implantation of the embryo is delayed until late fall. Birth follows in mid-winter with typically two blind and naked cubs, although litters may range from one to four, rarely five, young. The young nurse while the female continues her winter rest and then leave the den in the spring. The family remains together with the mother providing milk until late summer or early fall, sometimes longer. After weaning, the cubs stay with the mother for one or two years. American black bears become sexually mature at about 3–6 years of age, with the females maturing on average about a year earlier than the males.

conservation status

Not listed by the IUCN.

significance to humans

Hunted for meat, trophies, and hides, as well as various body organs and parts for cultural medicinal uses. American black bears are not normally aggressive, and only very rarely harm humans. They do, however, occasionally become pests to campers, beekeepers, farmers, and others who usually unintentionally furnish food sources.

Brown bear

Ursus arctos

subfamily

Ursinae

taxonomy

Ursus arctos Linnaeus, 1758, "sylvis Europaelig frigidaelig" assumed to be northern Sweden. Five subspecies.

other common names

English: Grizzly, kodiak, coastal brown bear, Alaskan brown bear, Asiatic brown bear, Russian brown bear, European brown bear, Himalayan snow bear, Syrian bear; French: L'ours brun; German: Braunbär; Spanish: Oso pardo.

physical characteristics

A large bear that varies in color from its typical brown to light tan or black. Large muscles create a noticeable shoulder hump that is further exaggerated in some geographic areas, particularly in North America, by a mane of long hairs with whitish-gray highlights. Its snout protrudes from a concave or "hollow" face. Females average from 250–450 lb (110–200 kg), and males from 350–850 lb (160–385 kg), although brown bears from some areas, including parts of Alaska, often reach 1,000 lb (450 kg) or more. Average adult size is about 3–4 ft (0.9–1.2 m) at the shoulder and 6–7 ft (1.8–2.1 m) when standing on the hind legs. Large bears may stand more than 8 ft (2.4 m) tall.

distribution

Widely distributed globally, with populations in North America from Alaska and northern Canada as far south as Wyoming, in Europe, in northern Asia, and in Japan.

habitat

Found in diverse habitats, particularly heavily wooded forests in Eurasia, and more open areas and tundra in North America.

behavior

Other than females with their cubs, brown bears are mostly solitary animals. If food is plentiful, however, they will share one area. For example, it is not uncommon to see several brown bears along a shallow river during a salmon run. Brown bears are usually most active at dawn and dusk, but may be active at any time. A hierarchy of sorts often forms, with the largest males keeping smaller individuals from approaching them too closely.

feeding ecology and diet

Omnivores, brown bears mainly subsist on grasses and plant roots, but will also dig up and eat ants, catch fish using their jaws and paws, and take both small and large mammals, including moose, caribou, and even American black bears. They also occasionally eat carrion.

reproductive biology

Polygamous. Breeding season is an occasion when bears abandon their solitary ways, with pairs forming for up to two weeks. However, a female may mate with more than one male, and have cubs in the same litter with different fathers. Mating occurs from mid-spring to mid-summer, with implantation of the embryo following in the fall. Females typically have two cubs, although a litter may range from one to four. Births occur in the winter. Weaned at about 5 months of age, the cubs stay under the protective care of their mother for at least two-and-a-half years, at which point she may breed again. Sexual maturity is attained at about 4–7 years of age, although competition for females may prevent a younger male from breeding as early as that.

conservation status

Not listed by the IUCN, although it has diminished greatly from its historical range.

significance to humans

Hunted primarily as trophies, but once hunted for their meat and hides. Various organs and body parts are also currently sought by Asian markets. Brown bears can be aggressive and have been known to attack humans, although this is rare.

Giant panda

Ailuropoda melanoleuca

subfamily

Ailuropodinae

taxonomy

Ailuropoda melanoleuca (David, 1869), "Mou-pin."

other common names

English: Cat bear, black and white bear; French: Le grand panda; German: Großer Panda; Spanish: Oso panda.

physical characteristics

Striking black-and-white bear with black fur around the eyes, on the ears, on all four legs, and across the back from shoulder to shoulder. Sometimes the black fur is replaced with reddish black or brownish fur. Unusually, it has six digits on each front foot, with the sixth digit actually an extension of the sesamoid bone and serving as an opposable thumb, thus giving the panda additional dexterity. This stocky bear reaches about 5.5–6 ft (1.7–1.8 m) in body length and weighs about 175–280 lb (80–125 kg), with the females about 10–15 percent lighter than the males.

distribution

Narrowly distributed in small parts of the Tibetan plateau in southwestern China.

habitat

Bamboo jungles 4,000–12,000 ft (1,200–3,600 m) above sea level.

behavior

These are mainly solitary animals, except for female-and-cub groupings. Males and females have home ranges. A male's range excludes other males, but may overlap with the range(s) of one or more females. Territories are maintained by scent markings on trees or other surfaces, and by tree scratches. Males and females vocalize, with females doing most of their sound-making during the breeding season. Males may compete for females.

feeding ecology and diet

Primarily eat bamboo, including the leaves, stems, and shoots. They are the most vegetarian of the bears, eating little other than bamboo. They have flattened molars and a specialized digestive system to handle the tough plant material.

reproductive biology

Polygynous and promiscuous. Mating occurs in spring, with litters of one to three cubs born in late summer to early fall. Despite the size of the litter, the mother commonly only rears one of her cubs. The cub weans at about nine months, and stays with their mother for about one-and-a-half years. Sexual maturity is attained at about 5–7 years of age, although competition for females may prevent a younger male from breeding that early.

conservation status

Listed as Endangered by the IUCN.

significance to humans

Particularly important to the tourism industry. Panda bears are a major attraction in zoos, and a symbol of species conservation efforts.

Polar bear

Ursus maritimus

subfamily

Ursinae

taxonomy

Ursus maritimus Phipps, 1774, Norway.

other common names

English: Sea bear; French: L'ours blanc, l'ours polaire; German: Eisbär; Spanish: Oso polar.

physical characteristics

A large, white to yellowish bear with a black nose, small eyes, fairly small ears, and a neck that is long compared to other bears. Under the "white" fur (actually made up of clear, hollow hairs), it has black skin. A marine animal, polar bears also have webbed front paws to aid in swimming. The largest of the terrestrial carnivores, male polar bears can reach 8–9 ft (2.4–2.7 m) in body length, 4 ft (1.2 m) at the shoulder, and more than 10 ft (3 m) when standing on their hind legs. Males commonly weigh 900–1,300 lb (400–590 kg), although very large males have been recorded that weighed in excess of 2,000 lb. (907 kg) and stood more than 12 ft (3.6 m). The average female body length ranges from about 6–7 ft (1.8–2.1 m), and they weigh 450–600 lb (200–270 kg).

distribution

Circumpolar distribution, ranging to the edge of the Arctic Ocean ice pack. They are found well into northern Canada, Europe and Asia in warmer months, and as far south as Newfoundland, Canada, and the northern Bering Sea in the winter.

habitat

Arctic snow and ice fields, with southern populations sometimes summering on land. Because they spend a considerable time on the ice pack or in the water, they are sometimes considered a marine mammal.

behavior

Not territorial animals, polar bears normally live alone on large home ranges. Females and cubs are the only social unit. Males

compete for receptive females during mating season. Pregnant females spend much of the winter in dens burrowed in the permafrost, but other polar bears generally do not enter winter dormancy, instead remaining active all year. Some of the females' dens go back many years, with the successive generations clawing farther down to make ever-deepening caverns.

feeding ecology and diet

Typically designated as carnivores because the vast majority of their diet is meat, particularly seals and fish. Ambush is a favored hunting method, with the polar bears waiting at holes in the ice for a seal to surface, then delivering a fatal blow with their clawed paws. The bears will also occasionally attack and eat other marine animals, including walruses and even beluga whales. During the summer, polar bears will subsist on berries, grasses and other vegetation, and carrion.

reproductive biology

Polygamous. Mating occurs in the spring, with implantation of the embryo following in late fall. Females typically have two cubs, although a litter may range from one to three, rarely four. Births occur in early winter. The cubs stay with their mother for at least two-and-a-half years, at which point she may breed again. Sexual maturity is attained at 3–6 years of age.

conservation status

Listed as Lower Risk/Conservation Dependent by the IUCN, although some scientists believe they could face extinction within the century if global warming continues to melt arctic ice.

significance to humans

Now protected, they were once widely hunted for their fur, meat, and trophy value. Polar bears can be aggressive, and have been known to attack humans, although this is very rare.

Spectacled bear

Tremarctos ornatus

subfamily

Tremarctinae

taxonomy

Tremarctos ornatus (F. G. Cuvier, 1825), Chile.

other common names

French: L'ours à lunettes; German: Brillenbär; Spanish: Oso de anteojos, oso frontino o andino.

physical characteristics

A smaller, black, brown or slightly reddish bear with whitish fur "spectacles" completely or partially encircling the eyes. Small, whitish stripes and patches typically run along on the sides of the face, the neck and chest. Body length is about 5–6 ft (1.5–1.8 m), with males weighing 220–340 lb (100–150 kg) and females 140–180 lb (65–80 kg).

distribution

South America, including parts of Bolivia, Colombia, Ecuador, Peru, and Venezuela.

habitat

Variable, but commonly in thick, lush forests of mountainous areas ranging from 6,000–9,000 ft (1,800–2,750 m). Also found as low as 600 ft (180 m) and as high as 14,000 ft (4,300 m), and in drier, open areas.

behavior

Active at dawn, dusk, and through the night, these bears spend much of their time on platforms, which they build of broken branches in trees, typically among fruiting branches. Between naps on the platform, they spend their time harvesting and eating the fruit. During mating season, males and females come together for one or two weeks, beginning by mock fighting apparently to stimulate the female for mating, and then copulating multiple times. Some communicative vocalizations have been documented between captive mothers and cubs.

feeding ecology and diet

These omnivorous bears prefer fruits and various parts of bromeliads, but also will eat orchid bulbs, grasses, small mammals, and birds.

reproductive biology

Monogamous. Mating occurs from spring to early summer, followed by delayed implantation, then birth in late fall to mid-winter with one to three cubs, although three is rare. The cubs remain with the mother, often riding on her back as she moves through the forest. Spectacled bears become sexually mature at about 4–7 years of age.

conservation status

Listed as Vulnerable by the IUCN.

significance to humans

Hunted for meat and fur, also for their fat, which is used for medicinal purposes. Due to their large fruit diet, spectacled bears are also important seed dispersers. Farmers and ranchers sometimes view the bears as a threat to their crops and livestock.

Resources

Books

Craighead, L. Bears of the World. Blaine, WA: Voyager Press, 2000.

Heldmaier, G. and M. Klingenspor, eds. Life in the Cold: The 11th International Hibernation Symposium. New York: Springer-Verlag, 2000.

Kays, R., and D. Wilson. Mammals of North America (Princeton Field Guides). Princeton: Princeton University Press, 2002.

Wilson, D., and Reeder, D. Mammal Species of the World, a Taxonomic and Geographic Reference. 2nd ed. Washington, DC: Smithsonian Institution Press, 1993.

Periodicals

Liu, J., G. C. Daily, P. R. Ehrlich, and G. W. Luck. "Effects of household dynamics on resource consumption and biodiversity." Nature 421 (Jan. 12, 2003): 530–533.

Loucks, C., et al. "Giant pandas in a changing landscape." Science 294 (Nov. 16 2001): 1465

Milius, Susan. "The lives of pandas." Science News 159 (Jan. 27, 2001): 61–3.

Mills, J. "Milking the bear trade (for their bile; sidebar with illustrations and data on bears throughout the world)." International Wildlife 22 (1992): 38–45.

Slattery, J., and S. O'Brien. "Molecular phylogeny of the red panda (Ailurus fulgens)." The Journal of Heredity 86 (November/December 1995): 413–22.

Tyson, P. "Secrets of Hibernation," <http://www.pbs.org/wgbh/nova/satoyama/hibernation.html>

Zhang, Y-P., Ryder, and A. Oliver. "Mitochondrial DNA sequence evolution in the Arctoidea." Proceedings of the National Academy of Sciences of the United States of America 90 (1993): 9557–61.

Organizations

American Bear Association. P.O. Box 77, Orr, MN 55771 United States. Phone: (218) 757-0172. E-mail: [email protected] Web site: <http://www.americanbear.org/>

Great Bear Foundation. P.O. Box 9383, Missoula, MT 59807 United States. Phone: (406) 829-9378. Fax: (406) 829-9379. E-mail: [email protected] Web site: <http://www.greatbear.org>

IUCN/SSC Bear Specialist Group. Harry V. Reynolds, Alaska Dept. of Fish and Game-Fairbanks, 1300 College Rd., Fairbanks, AK 99701 United States. Phone: (907) 459-7238. Fax: (907) 459-9723. E-mail: [email protected] Web site: <http://www.iucn.org/themes/ssc/pubs/bears511.htm>

Ursus International Conservation Institute. P.O. Box 832, Pincher Creek, Alberta T0K 1W0 Canada. E-mail: [email protected] Web site: <http://www.ursusinternational.org/>

Other

Animal Diversity Web. University of Michigan Museum of Zoology. <http://animaldiversity.ummz.umich.edu/chordata/mammalia/carnivora/ursidae.html>

The Bear Den. <http://www.bearden.org/blkbear.html>

Bears.org. <http://www.bears.org/animals/>

Hilton-Taylor, C., (comp.) 2000 IUCN Red List of Threatened Species. IUCN/SSC: Gland, Switzerland and Cambridge, UK, 2000. <http://www.redlist.org>

Nowak, R. "Black, Brown, Polar, Sun, and Sloth Bears." In Walker's Mammals of the World Online. The Johns Hopkins University Press, 1995. <http://www.press.jhu.edu/books/walker/carnivora.ursidae.ursus.html>

National Science Foundation. Press release NSFPR 03-06. Jan. 12, 2003. "Researchers Tie Worldwide Biodiversity Threats to Growth in Households: Pandas in China face encroachment, as do other species in global hotspots." <http://www.nsf.gov/od/lpa/news/03/pr0306.htm>

Smithsonian National Museum of Natural History. <http://www.nmnh.si.edu>

Leslie Ann Mertz, PhD