Bears have big heads, round ears, small eyes that face forward, very short tails, and stocky legs. They are plantigrade, walking on the heels and soles of their feet like humans do. Each paw has five curved claws that are not retractable, or cannot be pulled back.
Bears come in many colors, from the familiar black, brown, and white to blonde, cinnamon, and blue-gray. Some have a yellow, orange, or white chest marking in the form of a patch, a letter V or U, or a short horizontal line. Spectacled bears are called “spectacled” because of the light markings around their eyes. Among Malayan sun bears, the smallest species, males are 4 to 5 feet (1.2 to 1.5 meters) long and weigh between 60 and 150 pounds (27 and 70 kilograms). In comparison, male polar bears on average are 8 to 9 feet (2.4 to 2.7 meters) long and weigh 900 to 1,300 pounds (400 to 590 kilograms). Females, or sows, of all species are usually smaller than males, or boars.
Spectacled bears are found in Bolivia, Colombia, Ecuador, Peru, and Venezuela. Brown bears live in the United States, Canada, Europe, and Asia. American black bears inhabit the United States, Mexico, and Canada. Malayan sun bears, sloth bears, and Asiatic black bears thrive in Asia. Giant pandas live in China, while polar bears occupy the Arctic regions.
Bears live in a variety of habitats. For example, spectacled bears can be found in the dense rainforests of South America, and Malayan sun bears thrive in tropical rainforests in Southeast Asia, while polar bears live on the Arctic tundra.
Bears are generally omnivores, eating both plants and animals. However, the polar bear is almost entirely carnivorous, eating mainly ringed seals, while the giant panda lives exclusively on bamboo. The sloth bear favors termites and ants. The other species, while preferring plant sources, also eat young animals and fish.
BEHAVIOR AND REPRODUCTION
Bears maintain a solitary lifestyle, living alone, except when mating and rearing their young. When food is plentiful, they share but keep their personal space. Bears are usually crepuscular (active at dawn and dusk). Their excellent memory enables them return to past food sources. They are agile tree climbers and fast runners, reaching speeds of up to 30 miles per hour (48 kilometers per hour). Polar bears and Asiatic black bears are expert swimmers.
Most bears mate during spring or summer, but the fertilized egg undergoes delayed implantation, during which it takes up to six months to attach to the uterus and start developing. As a result, cubs are born tiny, ranging in weight from about 11 ounces (325 grams) in sun bears to 21 ounces (600 grams) in polar and brown bears. Most sows have two cubs, although some have as many as five. Depending on the species, cubs may stay with their mothers for one to more than four years.
BEARS AND PEOPLE
People hunt some bear species for meat and trophies. Some Asian cultures use bear parts to treat diseases. In addition, many zoos house bears as exhibit animals.
The giant panda is considered Endangered, facing a very high risk of extinction, or dying out, in the wild. The spectacled, sloth, and Asiatic black bears are considered Vulnerable, facing a high risk of extinction in the wild. These and other bear species are threatened by declining populations due to losing habitat, as humans clear more land for agriculture, mining, and other activities.