Polar Bear

Common Name: Polar Bear

Class: Mammalia

Order: Carnivora

Family: Ursidae

Genus: Ursus

Species: Ursus maritimus



Polar bears belong to the bear family, Ursidae, which also includes black bears, brown bears, and spectaled bears, in the Mammalian Order Carnivora.  Its scientific name is Ursus maritimus, which means "sea bear".  The polar bear is the largest land carnivore on the planet, and the only other member of Carnivora, along with the sea otter, that is a Marine Mammal.

They are the only bears that have fur on their feet.  This helps them grip the ice.  Males are 7-9ft long and can weigh 700-1600lbs.  Females are smaller weighing 330-550lbs.  Their bodies are built to survive in the extreme cold of an icy environment and freezing water.  These conditions reach temperatures as low as -50F.  Their blubber can be 4.5 inches thick. Extremely dense fur covers black skin.  Black skin absorbs all available sunlight, warming the bear during daylight hours.  The fur is hollow to help insulate against the cold.  Although the bear's fur looks white, it is actually pigment free.  It looks white because it reflects light like snow does.  They have wide webbed front feet, and are powerful swimmers.  Their long streamlined bodies help them swim 20-30 miles at a time.


The polar bear's range extends throughout the Arctic circle,  including Alaska, Canada, Russia, Denmark, and Norway.  Polar bears are omnivores eating mostly other marine mammals including seals, young walruses and even whales.  A beluga was attacked and killed while breathing at an ice hole by a polar bear.  They will also take advantage of a carcass and eat vegetation during the summer months.  The species of seal commonly hunted by polar bears are the ringed seal and bearded seal.  Polar bears are known to hunt and eat humans.  Only a small handful of animals, including tigers, lions, great white sharks, Komodo dragons, Australian saltwater crocodiles and anacondas are known to hunt, kill and eat humans.


Polar bears are solitary animals coming together only to mate, rear their young and if there happens to be a large kill around the vicinity.  Although mating takes pace in April or May, the fertilized egg does not implant until the fall. This is known as delayed implantation.  During the winter, pregnant females will build a den in the snow to give birth to two cubs.  Each cub weighs slightly more than a pound.  The cubs will stay with their mother for 18 months learning how to hunt. 


Polar bears are potentially threatened.  Their lives are affected by the any increase in global climate.  Such a climate change may be caused by humans introducing carbon dioxide and other greenhouse gases.  Polar bears require the large amounts of ice present in the arctic for survival.  Although most polar bears live far from heavily populated human areas, pollution still has adverse effects.  Chemical pollutants travel by wind and precipitation, eventually reaching even the most remote arctic regions.  These pollutants will then carry through the food chain and accumulate within predators like polar bears, resulting in disease and eventually death.  Drilling, mining, fishing, hunting and the broad spectra of other human interactions also threaten the lives of polar bears.


Content provided by Canisius College students under the direction of Michael Noonan, PhD.