The sloth bear is small and usually black, with a long shaggy coat, especially over the shoulders. Brown and gray hairs may be mixed in with the dark coat, and cinnamon and reddish individuals have also been reported. It has a distinctive whitish or yellowish chest patch in the shape of a wide U, or sometimes a Y if the lower part of the white hairs extend down the chest. The snout is light colored and mobile. The nostrils can be closed voluntarily. It is thought that the reduced hair on the muzzle may be an adaptation for coping with the defensive secretions of termites.
Adults are 150 to 190 centimeters (60 to 75 inches) long. Males weigh 80 to 140 kilograms (175 to 310 pounds), and females weigh 55 to 95 kilograms (120 to 210 pounds).
Sloth bears are found in forested areas and in grasslands, predominantly at lower elevations. They apparently favor drier forests and have been reported to prefer areas with rocky outcrops.
Most sloth bears are found in India and Sri Lanka, but they have also been reported from Bangladesh, Nepal, and Bhutan.
Mating occurs in May, June, and July. In captivity, mating pairs come together for only one or two days during which time there may be considerable vocalizing and fighting. Gestation lasts from six to seven months. Most litters consist of either one or two cubs, but litters of three cubs have been reported. Cubs are born in earth dens and apparently do not leave them until they are two to three months old. The cubs stay with their mothers until they are nearly adult, at two or more years of age.
There is little information on social organization, but observations in the wild suggest sloth bears live as solitary individuals, except for females with cubs. Limited observations suggest sloth bears may have small home ranges. They give several vocalizations, but their functions are not understood.
Sloth bears feed extensively on termites and have special adaptations for doing this: The naked lips are capable of protruding, and the inner pair of upper incisors are missing, which forms a gap through which termites can be sucked. The sucking noises made by feeding in this manner can apparently be heard from over 100 meters (330 feet) away. They also eat eggs, other insects, honeycombs, carrion, and various kinds of vegetation. In Nepal, they eat fruits extensively when in season, from March to June.