Sloth bears, Ursus ursinus, were named when the first pelts were sent to England from India in the 1700s; hearing that they hung from trees, zoologists erroneously classified them as sloths, and called them bear sloths. In 1810 a live sloth bear was shipped to Paris; the error was discovered and the name reversed.

Sloth bears are native to Sri Lanka, India, Bhutan, Nepal and Bangladesh, where they live in forests. They are heavy and squat, weighing about 125 to 145 kg (280 to 300 lb); the females are just a little smaller than the males, unlike most bear species, where the male is twice the size of his mate. Sloth bears have long shaggy dark coats with especially long fur around the neck, giving the appearance of a mane, and a light-coloured chevron marking on their chests. They move with a slow, shuffling gait, but if riled, can gallop faster than a human.

The main food source of the sloth bear is termites and ants, and its whole head is adapted to best consuming these insects: its muzzle is long with protruding lips and nostrils which can be closed voluntarily; it has no front teeth and its upper palate is hollowed out, all of which allows the sloth bear to form its lips and teeth into a vacuum tube. The bears feed by digging into the termite mounds and sucking out the termites with great efficiency and also, apparently, great noise. They also eat fruits, flowers, honey and carrion.

Because of their abundant food sources and the warm climes they favour, sloth bears do not appear to hibernate. Also, unlike other bear species, they are fairly sociable; they don't mind other bears in their territory and communicate with a variety of loud hoots, gurgles, and squeals. They are apparently particularly noisy when mating.

Sloth bears are nocturnal. Though they aren't particularly aggressive, they can become very absorbed in what they're doing and not notice an approaching person; startled, they may rear up, roar, and either run away or attack. So watch who you're jostling in the South Asian forest at night.