Physical Characteristics

Polar Bears

Physical Characteristics

Size

  1. The polar bear is the largest land carnivore.
  2. Male polar bears (boars) grow two to three times the size of females (sows). Boars weigh about 350 to more than 650 kg (772-1,433 lb.) and are about 2.5 to 3 m (8.2-9.8 ft.) long.
  3. Sows weigh about 150 to 250 kg (331-551 lb.) and are about 1.8 to 2.5 m (6.0-8.2 ft.) long. Pregnant females can weigh as much as 500 kg (1,102 lb.).
  4. The largest polar bear ever recorded was a male weighing 1,002 kg (2,209 lb.) and measuring 3.7 m (12 ft.) long.

Polar bears are one of the largest land carnivores.

Body Shape

  1. Compared to other bears, polar bears have more slender bodies and longer necks and heads.

Polar bears have longer necks than other bears.

Coloration

  1. The coat can vary from pure white to yellow to light brown depending upon season and angle of light.

Limbs

  1. The hind limbs are longer than the forelimbs. This makes the large, muscular hind end stand higher than the shoulders.
  2. Feet are five-toed paws.
    • Polar bears have large paws compared to body size, reaching 30 cm (12 in.) in diameter. The large paws of a polar bear act like snowshoes, spreading out the bear's weight as it moves over ice and snow.
    • Polar bear paws can reach 30 cm (12 in.) in diameter.

    • The forepaws are round and partially webbed. The hind paws are elongated.
    • Each toe has a thick, curved, non-retractile claw. The claws are used for grasping prey and for traction when running or climbing on ice.
    • The sole of a polar bear's foot has thick, black pads covered with small, soft papillae (dermal bumps). The papillae create friction between the foot and ice to prevent slipping. Long hairs growing between pads and toes also help prevent slipping.

The soles of polar bears' feet have thick, black pads with long
hairs growing between that prevent slipping on the ice.

Head

  1. A polar bear's head is oblong and relatively small compared to body size. The muzzle is elongated with a "Roman-nosed" (slightly arched) snout.
  2. The nose is broad and black.
  3. Polar bears have a longer, more oblong head
    and muzzle than other bears.

  4. Teeth.
    • Polar bears have 42 teeth, which they use for catching food and for aggressive behavior.
    • Polar bears use their incisors to shear off pieces of blubber and flesh.
    • Canine teeth grasp prey and tear tough hides.
    • Jagged premolars and molars tear and chew.
    • Polar bears swallow most food in large chunks rather than chewing.
  5. A polar bear's eyes are dark brown, set relatively close together, and face forward.
  6. The ears are small compared to those of other bears - an adaptation that enables them to conserve body heat.

Tail

  1. The tail is small, about 7 to 12 cm (2.8-4.7 in.) long.

Hair

  1. Polar bears are completely furred except for the nose and footpads.
  2. A polar bear's coat is about 2.5 to 5 cm (1-2 in.) thick. A dense, woolly, insulating layer of underhair is covered by a relatively thin layer of stiff, shiny, hollow guard hairs. Guard hairs may be as long as 15 cm (6 in.).
  3. Though really translucent, the hairs appear white because of their highly reflective quality. Oxidation from the sun, or staining, can make the hairs look yellow or brown.
  4. Polar bear fur is oily and water repellent. The hairs don't mat when wet, allowing the polar bears to easily shake free of water and any ice that may form after swimming. Ice forms when the wet fur is exposed to air temperatures at or below freezing.
  5. Polar bears have water repellent hair. The oils keep the
    hairs from matting when wet so it is easy for the bears to shake off water and ice.

  6. Polar bears completely molt (shed and replace their fur) annually, in May or June. The molt can last several weeks.

Skin

  1. A polar bear's skin, visible only on the nose and footpads, is black. The black color enables the bear to absorb sunlight energy to warm its body.