Sloth bear

Appearance

Sloth bears are distinguished from Asian black bears by their lankier builds, longer, shaggier coats, pale muzzles and white claws.

Sloth bear muzzles are thick and long, with small jaws and bulbous snouts with wide nostrils. They have long lower lips which can be stretched over the outer edge of their noses, and lack upper incisors, thus allowing them to suck up large numbers of insects. The premolars and molars are smaller than in other bears, as they do not chew as much vegetation.

In adults, the teeth are usually in poor condition, due to the amount of soil they suck up and chew when feeding on insects. The back of the palate is long and broad, as is typical in other ant-eating mammals. The paws are disproportionately large, and have highly developed, sickle-shaped, blunt claws which measure 4 in in length.

Their toe pads are connected by a hairless web. They have the longest tail in the bear family, which can grow to 6–7 in. Their back legs are not very strong, though they are knee-jointed, and allow them to assume almost any position. The ears are very large and floppy. Sloth bear fur is completely black, save for a whitish Y- or V-shaped mark on the chest. This feature is sometimes absent, particularly in Sri Lankan specimens.

This feature, which is also present in Asian black bears and sun bears, is thought to serve as a threat display, as all three species are sympatric with tigers.

The coat is long, shaggy, and unkempt, despite the relatively warm enivronment in which the species is found, and is particularly heavy behind the neck and between the shoulders, forming a mane which can be 30 cm long. The belly and underlegs are almost bare.

Adult sloth bears are medium-sized bears, weighing around 130 kg on average, though weight can range variously from 55 to 124 kg in females and from 80 to 192 kg in males. They are 60–90 cm high at the shoulder, and have a body length of 1.4–1.9 m. Females are smaller than males, and have more fur between the shoulders.

Status

The sloth bear is listed in Schedule I of the Indian Wildlife Protection Act, 1972, which provides for legal protection of sloth bears. International trade of the sloth bear is prohibited as it is listed in Appendix I of the Convention on International Trade in Endangered Species.

To address the human-bear conflict, people may be educated about the conservation ethics, particularly among locals. To resolve this conflict, the basic issue of deteriorating habitat, which is the reason for the conflict between people and bears, improvements through government or community-based reforestation programmes, may be promoted.

The population of sloth bears grows when they live in high-profile reserves that protect species, such as tigers and elephants. Directly managed reserves could conserve the sloth bear and hence such reserves must be supported.

The government of India has banned use of sloth bears for entertainment, and a 'Sloth Bear Welfare Project' in the country has the objective of putting an end to the use of sloth bears for entertainment. However, their number in such activity is still large. Many organizations are helping in the conservation and preservation of sloth bears in safe places.

Behavior

Adult sloth bears may travel in pairs, with the males being gentle with cubs. They may fight for food. They walk in a slow, shambling motion, with their feet being set down in a noisy, flapping motion.

They are capable of galloping faster than running humans. Although they appear slow and clumsy, sloth bears are excellent climbers. They climb to feed and rest, though not to escape enemies, as they prefer to stand their ground. They are capable of climbing on smooth surfaces and hanging upside down like sloths.

They are good swimmers, and primarily enter water to play. To mark their territories, sloth bears will scrape trees with their forepaws, and rub against them with their flanks.

Sloth bears have a great vocal range. Gary Brown, in his "Great Bear Almanac", lists over 25 different sounds in 16 different contexts. Sounds such as barks, screams, grunts, roars, snarls, whickers, woofs, and yelps are made when angered, threatening, or when fighting. When hurt or afraid, they shriek, yowl, or whimper. When feeding, sloth bears make loud huffing and sucking noises, which can be heard over 100 m away. Sounds such as gurgling or humming are made by bears resting or sucking their paws. Sows will emit crooning sounds to their cubs.

The species is the most vociferous when mating, and make loud, melodious calls when doing so. Sloth bears do not hibernate. They make their day beds out of broken branches in trees, and rest in caves during the wet season. Sloth bears are the most nocturnal of bears, though sows become more active in daytime when with cubs.

Reproduction

The breeding season for sloth bears varies according to location: in India, they mate in April, May, and June, and give birth in December and early January, while in Sri Lanka, it occurs all year. Sows gestate for 210 days, and typically give birth in caves or in shelters under boulders. Litters usually consist of one or two cubs, or rarely three. Cubs are born blind, and open their eyes after four weeks.

Sloth bear cubs develop quickly compared to most other bear species: they will start walking a month after birth, become independent at 24–36 months, and become sexually mature at the age of three years. Young cubs will ride on their mother's back when she walks, runs, or climbs trees until they reach a third of her size. Individual riding positions are maintained by cubs through fighting. Intervals between litters can last two to three years.

Food

Sloth bears are expert hunters of termites, which they locate by smell. On arriving at a mound, they scrape at the structure with their claws till they reach the large combs at the bottom of the galleries, and will disperse the soil with violent puffs.

The termites are then sucked up through the muzzle, producing a hoovering sound which can be heard 180 m away. Their sense of smell is strong enough to detect grubs three feet below ground. Unlike other bears, they do not congregate in feeding groups. They rarely prey on other mammals.

Sloth bears may supplement their diet with fruit and plant matter; in March and April, they eat the fallen petals of mowha trees and are partial to mangoes, sugar cane, the pods of the golden shower tree and the fruit of the jack-tree. Sloth bears are extremely fond of honey. When feeding their cubs, sows are reported to regurgitate a mixture of half-digested jack fruit, wood apples, and pieces of honeycomb.

Evolution

Sloth bears may have reached their current form in the early Pleistocene, the time when the bear family specialized and dispersed. A fragment of fossilized humerus from the Pleistocene, found in Andhra Pradesh's Kurnool Basin is identical to the modern sloth bears. The fossilized skulls of a bear once named "Melursus theobaldi" found in the Shivaliks from the early Pleistocene or early Pliocene are thought by certain authors to represent an intermediate stage between sloth bears and ancestral brown bears. "M. theobaldi" itself had teeth intermediate in size between sloth bears and other bear species, though its palate was the same size as the former species, leading to the theory that it is the sloth bear's direct ancestor. Sloth bears probably arose during the mid-Pliocene and evolved in the Indian Subcontinent. The sloth bear bears evidence of having undergone a convergent evolution similar to that of other ant-eating mammals.