Polar Bear

POLAR BEAR: PHYSICAL CHARACTERISTICS

The polar bear, a species synonymous with the Arctic region, is the largest bear species and the largest predator at the apex of the Arctic ecosystem’s food chain place. This species spends the majority of its life along coastal areas, in water, or on sea ice ocean sea, and is scientifically named Ursus maritimus, meaning “sea bear.”

The weight of an adult male polar bear ranges from 350 kg to 700 kg. When standing on its hind legs, its height measures between 2.4 m and 3 m. Average weight varies depending on the region. For example, males living near the Beaufort Sea have an average weight of 450 kg. Adult females weigh between 150 kg and 250 kg, approximately half the weight of males. However, during pregnancy, their weight can reach up to 500 kg. According to the Guinness Book of World Records, the heaviest recorded polar bear weighed 1002 kg.

DIFFERENCES FROM OTHER BEARS

Compared to its closest relative, the brown bear, the polar bear has a more elongated body, a longer skull, and a longer snout. Its large paws distribute its weight when walking on thin ice and snowpacks snow, and provide powerful propulsion while swimming. In adult polar bears, the length of the canine teeth can reach up to 30 cm. The polar bear’s fur provides effective insulation against cold temperatures thanks to a layer of blubber up to 10 cm thick. Its skin is actually entirely black. The fur consists of a dense undercoat and a protective outer layer of transparent hairs that appear white. Unlike other white-furred Arctic animals (see Arctic fox), the hairs do not darken during summer months camouflage; instead, as they age, the fur begins to take on a yellowish tint. In males, certain hairs on the front paws grow longer than the rest until about 14 years of age. It is believed these hairs serve a function similar to a lion’s mane like, helping to attract females important.

The polar bear is not a territorial species like the brown bear. Although considered an aggressive predator due to its strength, it is generally cautious and prefers to flee rather than attack. Human interactions remain limited degree, so its behavior toward humans is unpredictable; although rare, attacks, killings, and consumption of humans have been reported.

SURVIVAL AND REPRODUCTION STRATEGIES

The polar bear’s exceptional sense of smell plays a major role in its success as a hunter. It can detect the scent of seals up to 1.6 km away and through 1 meter of snow. Polar bears are skilled swimmers and can travel long distances without stopping, remaining in the water for days. In a 2008 study, an adult female polar bear was tracked via satellite tag. This bear swam continuously for 9 days across the Bering Sea to reach sea ice 700 km away, then swam an additional 1800 km with intermittent breaks. It was determined that the bear lost 22 percent of its total body weight during this journey.

Although polar bears can cover increasing distances between melting sea ice due to climate change, such journeys demand excessive energy expenditure road. The same study observed that a one-year-old cub accompanying its mother could not complete such a long and energy-intensive journey.

The polar bear’s body, rich in fat, allows it to float easily. It swims in a dog-paddle style using its large front paws and can reach speeds of up to 10 km/h. Its walking gait is clumsy, averaging 5.6 km/h hour movement. However, when chasing prey, it can reach speeds of up to 40 km/h.

Adult polar bears generally live solitary lives. However, it is known that polar bears sometimes play together for hours without any signs of aggression. Polar bears communicate with each other through a variety of vocalizations. Females emit moans, growls, and murmurs when communicating with cubs, calling for help, or when stressed; similar murmuring sounds have also been recorded from cubs while nursing. In addition to vocalizations, polar bears use chemical communication through scent marks. During travel, they leave strong odors from glands in their paws to signal their path to other polar bears, helping them avoid intraspecific conflicts and signal their presence to potential mates across the vast Arctic landscape possible.

FOOD SOURCES AND HUNTING BEHAVIORS

To survive, polar bears require large quantities of food and fat, spending more than half their time searching for prey. As the most carnivorous member of the bear family, their diet consists largely of ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus). Seals must surface through holes in the sea ice to breathe and return to these openings at regular intervals. These breathing holes are the primary locations where polar bears lie in ambush to hunt seals.

After detecting seal breathing holes with their acute sense of smell, polar bears lie in wait nearby. This waiting period can last for hours. When a seal approaches a hole to breathe, the bear uses its long, powerful forelimbs to lunge and drag the seal onto the ice on. Another hunting technique involves stealthily approaching seals resting on the ice. The bear may approach within 90 meters without being detected, then cover the remaining distance by crawling. When the distance reduces to 9 to 12 meters, it launches its attack. Another commonly used strategy is raiding maternity dens that female seals dig into snowdrifts. In addition to its two primary seal prey, the polar bear also feeds on other species such as the harp seal (Pagophilus groenlandicus), harbor seal (Phoca vitulina), and hooded seal (Cystophora cristata). The size of prey varies according to the sex and age group of the bear. Adult males consistently target larger prey. Rarely, polar bears have been observed attacking walruses weighing more than twice their own body weight.

HABITATS AND CURRENT STATUS

The polar bear is a sea ice-dependent species that relies on ice for traveling, hunting, and finding mates. Melting sea ice due to climate change and global warming directly impacts polar bears. Additionally, the intrusion of toxic pollutants into their natural habitats, the expected increase in shipping traffic, subsea resource exploration and extraction activities, and tourism centered on polar bear observation all pose threats to this species risk. For these reasons, the polar bear is considered one of the flagship species for climate change mitigation efforts and is classified as “vulnerable” on the International Union for Conservation of Nature’s Red List.

Estimating the polar bear population is difficult due to its vast range extending to the most remote regions of the Arctic and its non-herd lifestyle. Furthermore, field studies monitoring polar bears are hindered by the extreme conditions of the region, which compromise researcher safety. Despite all these challenges, the International Union for Conservation of Nature reported in 2015 that the global polar bear population ranged between 22,000 and 31,000 individuals.