The World of Polar Bears

Physical Characteristics

A. Size

1. Polar bears are the largest land carnivore.
2. Male polar bears (boars) grow two to three times the size of female polar bears (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 (Stirling, 1988).
3. Sows weigh about 150 to 250 kg (331-551 lb.) and are about 2 to 2.5 m (6.6-8.2 ft.) long. Pregnant females can weigh as much as 500 kg (1,102 lb.) (Stirling, 1988).
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 (Domico, 1988).

B. Body shape

Compared to other bears, polar bears have elongated bodies and long slender necks.

C. Coloration

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

D. Limbs

1. The hind limbs are longer than the forelimbs. This makes the large, muscular hind end stand higher than the shoulders.
2. Polar bear legs are large and stocky.
3. Feet are five-toed paws.
   a. 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.
   b. The forepaws are round, and the hind paws are elongated.
   c. Each toe has a thick, curved, nonretractable claw. The claws are used for grasping prey and for traction when running or climbing on ice.
   d. 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 slippage. Long hairs growing between pads and toes also help prevent slippage.

E. 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. Teeth.
   a. Polar bears have 42 teeth, which they use for catching food and for aggressive behaviour.
   b. Polar bears use their incisors to shear off pieces of blubber and flesh.
   c. Canine teeth grasp prey and tear tough hides.
   d. Jagged premolars and molars tear and chew.
   e. Polar bears swallow most food in large chunks rather than chewing.
4. A polar bear’s eyes are dark brown, set relatively close together, and look forward.
5. The ears are small and rounded and lay flat when under water.

F.Tail

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

G.Hair

1. Polar bears are completely furred except for the nose and footpads, which are black.
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, clear guard hairs.
3. 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.
4. The hairs reflect light, giving a polar bear its white coloration. Oxidation from the sun, or staining, can make the hairs look yellow or brown.
5. Polar bears completely molt (shed and replace their fur) annually, in May or June. The molt can last several weeks.

H.Skin

A polar bear’s skin is black.