Reproduction
Sloth bears reach sexual maturity at about 3 to 4 years of age. Breeding season occurs at most any time in Sri Lanka, while breeding season is April-June in India. When mating, sloth bears are loud, and often engage in hugging or mock fighting. Gestation is 180-210 days in captivity. Like some bears, sloth bears can delay implantation of the fertilized embryo if the food supply is scarce. One to three cubs are born in the dry season, usually in December or early January. Birth occurs in a den, cave, or a shelter beneath boulders. Average birth weight is 10.5-17.5 ounces (300-500 g).

Life Cycle
Although newborn cubs have strong toes and forelegs, they are extremely tiny and blind at birth. Their eyes open in about three weeks, and they can walk at four weeks. Rapid growth occurs, mostly in the legs. Young receive nourishment from their protein-rich mother's milk for up to three years, but start to sample other foods when 2 to 3 months old. For cubs, extensive knowledge of their surroundings is critical to their survival, and the mother is considered a patient and sensitive teacher. Sloth bear cubs have a good chance of survival, as male sloth bears rarely display the predatory instincts toward cubs observed in other bear species. Cubs stay with their mother until they are independent and can care for themselves, at 2 or more years of age. Hence, females have breeding intervals of two or three years.

Sloth or Bear?
These animals were initially classified as bear sloths, due to their slow gait and ability to climb trees. Not until 1810 did the classification change; for sake of simplicity, the name was switched to sloth bear.

Sloth bears have a long, rough and shaggy coat of thick, reddish-brown to black fur. Similar to other species of Asian bears, they have a white or yellow mark on their chest shaped like a U, V or Y. There is little hair on their underbelly. Some sloth bears also have a white muzzle and white paw tips. Sloth bears prefer to forage at night, in a solitary fashion, when temperatures are cooler. However, females with cubs forage during the day, so as not to compete with other bears or nocturnal predators for resources.

Huff and Puff!
Perhaps another reason that sloth bears were thought to be sloths was their massive consumption of insects, especially termites. Because termite and ant colonies are an abundant and consistent source of food for sloth bears, they are the only bear specifically adapted for feeding on insects. Sloth bears dig out insect mounds with their sharp, 3-inch (7.6 cm) long claws. Then, they blow away the dirt and debris with their long, mobile lips. Finally, with a huge breath, the sloth bear sucks out the termites. Since sloth bears lack their two front incisors and have a hollowed palate, they can quickly remove the insects like a high-powered vacuum. Sloth bears also love honey, and they will easily climb up to 26 feet (8 m) into the trees or hang from branches to raid honeycombs.

Sloth bears have an excellent sense of smell, good vision and satisfactory hearing. Reliance on their sense of smell, rather than sight or hearing, can lead to confrontation between humans and sloth bears. Often, the shy sloth bear’s reaction to being startled is to attack savagely with a charge.

Woodland Park Zoo’s sloth bears can be found along the Trail of Adaptations at the bear grotto facing the North Meadow, next to the Malayan sun bears. Their exhibits provide a multilevel, naturalistic setting that contains major components of their normal habitat. Other species of bear at Woodland Park Zoo include brown bears in the Northern Trail exhibit.

Sloth bears are an endangered species. Less than 10,000 remain in the wild. Their survival is challenged by fragmented populations, competition with other animals (particularly humans) for space and food, deforestation, and the bear parts trade for use in traditional Asian medicines. Although protection has improved for sloth bears, some Asian countries still allow hunting of sloth bears and unrestricted trade of bear parts. Even in the USA, some states allow the sale of bear parts taken through hunting. For all bears, their long-term survival requires large, remote and protected areas of habitat, together with the elimination of the bear parts trade. The Association of Zoos & Aquariums (AZA) has a Species Survival Plan (SSP) for the sloth bear. The SSP is developing an in situ conservation program for the sloth bear, as well as sponsoring participation in bear research programs. Woodland Park Zoo will participate in SSP captive breeding programs and research.

How You Can Help!
The effort to save endangered species requires cooperation and support at the international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo or other conservation organizations of your choice. Do not buy products made from wild-caught animal parts. Contact your elected representatives and express your views about conservation of endangered species.

Contact Woodland Park Zoo at webkeeper@zoo.org to find out ways you can support conservation programs at the zoo. Learn other ways you can help conserve wildlife and the habitats they require for survival by visiting our How You Can Help page.

Sources and Suggested Reading
Domico, Terry. 1988. Bears of the World. Facts on File, New York, NY. 189 p.

Stirling, I., ed. 1993. Bears: Majestic Creatures of the Wild. Rodale Press, Emmaus, PA. 240 p.

For Kids!
Gilka, H., & Bale, A. 1993. Bears. Ticknor & Fields, New York, NY. 30 p.

Lynch, W. 1995. Bears, Bears, Bears. Firefly Books, Willowdale, Ontario, Canada. 63 p.

More References