Polar Bear (Ursus maritimus)
Order: Carnivora, Family: Ursidae
The polar bear has a thick, well-insulated coat comprising water-repellent guard hairs and a dense undercoat.
The polar bear's coat and a layer of fat beneath it help keep the bear warm in its arctic habitat.
The polar bear's fur is not soft, but quite oily, which helps repel water. It measures about 1 1/2 inches thick, and can vary in color from white to creamy-yellow to light brown.
Large and stocky, male polar bears grow up to 9 feet long and weigh as much as 1,500 pounds. Females weigh as much as 500 pounds and measure 8 feet long.
The polar bear's skin, nose and foot pads are black. Their paws can measure up to 12 inches in size.
II. GEOGRAPHICAL RANGE AND HABITAT:
- The polar bear has a thick, well-insulated coat comprising water-repellent guard hairs and a dense undercoat.
- The polar bear's coat and a layer of fat beneath it help keep the bear warm in its arctic habitat.
- The polar bear's fur is not soft, but quite oily, which helps repel water. It measures about 1 1/2 inches thick, and can vary in color from white to creamy-yellow to light brown.
- Large and stocky, male polar bears grow up to 9 feet long and weigh as much as 1,500 pounds. Females weigh as much as 500 pounds and measure 8 feet long.
- The polar bear's skin, nose and foot pads are black. Their paws can measure up to 12 inches in size.
- Polar bears are found in the Arctic, typically inhabiting islands and coastlines.
- Polar bears like to travel on ice flows most of the time and move around a lot to find food, dens and companions.
- An average polar bear can travel 20 miles a day, and can have home ranges of between 19,000 and 23,000 square miles of land.
- Approximately 28,000 polar bears exist in the wild. Although the species's numbers are increasing (due in part to governmental regulations on hunting polar bears), shrinking ice coverage in the Arctic poses a threat to its long-term survival.
IV. LIFE CYCLE/SOCIAL STRUCTURE:
- Opportunistic carnivores, polar bears feed on a variety of food, depending on their location. Most eat seals, beluga, harp, whales and narwhals.
- A polar bear can devour 15 to 20 percent of its body weight and swallows most food in very large chunks.
- If food is scarce, a polar bear will also eat berries, ducks, small rodents and even reindeer.
- Polar bears have been known to attack humans, but most often when humans live nearby and food is scarce in the polar bear's home range.
V. SPECIAL NOTES/ADAPTATIONS:
- Polar bears typically breed in the spring, around April on the sea ice. Female polar bears become sexually maturity at 4 years of age, while males begin to breed at 6 years.
- There are about three male polar bears to every female. As a result, males fight intensely with each other to secure a place with a breeding female. The fights last until one male drives the other one away.
- Male polar bears may have different mates over their lifetime.
- After mating, the female polar bear will gestate for about eight months. Females must gain about 450 pounds for a successful pregnancy.
- Females give birth to cubs typically around the end of the year, when they're hibernating.
- Born with their eyes closed, cubs weigh between 16 and 24 ounces and measure about a foot long.
- Bear cubs nurse on and off all day. By 1 month old, they open their eyes and begin to try walking.
- Three to four months after birth, the cubs emerge from the den with their mothers.
- Polar bear cubs stay with their mother until they are about 2 or 3 years old.
- Starvation poses the greatest threat to juvenile polar bears. They tend to be inexperienced hunters, and often are chased from kills by larger adults.
- Native arctic peoples still hunt polar bears, primarily for food, clothing and handicrafts.
- Hunting is regulated in Canada, Greenland and the United States, while Norway and Russia have banned hunting polar bears.
- Susceptibility to disease also threatens the polar bear. A parasite worm found in infected seals, a staple food for polar bears, can cause severely damaged hear and tissue problems.