Sun bears grow to only about half the size of an American black bear. Males, slightly larger than females, are about 5 feet (1.5 meters) in length and weigh up to 150 pounds (70 kilograms), a stature which suits their arboreal lifestyle and allows them to move easily through the trees. They have even been observed making sleeping platforms high above the ground out of branches and leaves.
Ironically, sun bears are nocturnal. They lumber through the forests by night, snacking on fruits, berries, roots, insects, small birds, lizards, and rodents. They have an excellent sense of smell and extremely long claws, exceeding four inches (ten centimeters) in length, which they use to rip open trees and termite nests. They also have an almost comically long tongue for extracting honey from bee nests, giving them their other nickname, “honey bear.”
Little is known about the social life of these bears, but there is some evidence that suggests they may be monogamous. Mother bears, called sows, make ground nests and give birth to one or two blind, helpless babies that weigh about 11 ounces (325 grams). Mothers have actually been observed cradling a cub in their arms while walking on their hind legs, a rare trait among bears. Cubs can move about after two months and are weaned by four months, but they remain with their mothers for two years or more.
Because of their remote habitat and shy personality, there is currently not enough data to determine if sun bears are in danger of extinction, but scientists fear the worst. Their homelands are being lost rapidly to deforestation, poachers hunt them mercilessly for body parts and fur, and some farmers kill them on site because they often eat crops such as oil palm, coconuts, and bananas. Adult females are also frequently killed so their cubs can be taken and raised as pets.