Fearless Polar Bear Mothers-

World's Largest Carnivore Mammal

(Nanook-Inuit Polar Bear word or by Vikings Ice/White Bear)

Scientific Latin Name- Ursus maritimus meaning sea bear

 

A fierce and ferocious protector best describes the polar bear mother as she defends her cubs throughout their growth in  the arctic's harsh and unforgiving environment.   In two years, these cubs will leave their mother's protection to start a new life ranging for the seasonal cycle in the snowy arctic tundra to sea ice hunting adventures in the Hudson Bay area.

 

In general, polar bear mothers weigh about 330-770lbs (150-350kg) and stand about 5.9-6.6ft (180-200cm) tall.  In contrast, male polar bears typically weigh about 770-1430lbs (350-650 kg) and stand 8-10 feet (240-260cm) tall.  

 

For perspective, polar bears evolved over 200,000 years ago from their significantly strong and muscular brown bear(grizzly) ancestors. The polar bear paws are partially webbed as an evolutionary adaptation to its massive paws about one foot in width used for swimming in the arctic ocean up to sixty miles a day.

 

Polar Bear mothers are sexually mature at four years old and males are ready to mate at about eight years old.  They will need time to continue to learn to navigate the arctic winter's sea ice and prove their survival capabilities on the Hudson Bay shoreline during spring, summer and fall.

 

Polar Bear cubs are born November through December in their mother's den.  Mothers emerge from the den with her cubs in late March and April. The polar bear is also capable of delayed implantation of her egg to select the best time for the polar bear's birthing for the best odds of its survival.

 

After about eight months of a Polar Bear mother's pregnancy, she can have her cubs provided she has the physical fat reserves.   At birth, polar bear cubs weigh about 16-24 oz. and are about twelve inches long.  Males are born slightly larger than females.

 

Most Polar Bear mothers give birth once every three years.  In areas with large food accessible, polar bear mothers can give birth about once every two years.

 

Polar Bear mothers most frequently have two cubs and sometimes follow with only one cub.   Having twin cubs is more the norm and having three or four cubs can be more unexpected. Too many cubs strains the polar bear mothers physical resources to help them all survive.

 

Polar Bear Mother Denning and Nursing Instincts-

The Polar Bear mother often returns to the same den site areas for her winter hibernation if she is pregnant.  Her instincts are her navigational compass back to her familiar denning area.

 

Intelligent and Alert, the Polar Bear mother knows she has to eat to continue to nurse her cubs in the first year of their life so they rapidly increase their size to just survive in the Arctic wilderness.  

 

From a pink-skinned, thin haired, temporarily blind and deaf polar bear cub weighing one pound or (0.6 kg) in their mother's den, they grow quickly at three months old to 22-26 lbs and when they leave the den in March or April they are 20-30 lbs. 

In the first three months, the cubs gain twenty times their birth weight.  Each following month they may gain another twenty pounds all from their mother's enriched milk through nursing.

 

Protecting her polar bear cubs takes her total commitment day and night to feed them and keep them warm in the folds of their mother's insulting fur.  The polar bear mother's life-saving body heat and insulated fur protects her young cubs especially when they are secure in her underbelly and wrapped by her immense forearms.  Her white fur also serves as camouflage so arctic land and large bird predators are less likely to locate her young cubs.

 

Outside the polar bear mother's den, her large head folds into her stomach to shield the cubs from the arctic winds since they need to frequently nurse. Her special hollow fur holds heat longer and her black skin underneath her fur also attracts heat.  In her arms, it is like a warm solar oven for her cubs' protection.  From the outside, an infrared camera cannot even capture her heat signature.

 

In the first year of the cub's life, they can weigh 250-300lbs. and their mother still nurses them even when she has little food to feed herself. These cubs need this body weight to be ready for the seal sea ice hunt beginning in November as the start of the Arctic winter.  Extra fat can be the critical key to their success in arctic life. 

 

Surprisingly, male cubs can weigh as much as their mother at two years of age when they are ready to leave their mother.  His added strength will carry her genes forward when he is ready to mate.

 

Her territorial boundaries are ever changing as the mother guides the cubs towards the frozen ice for the critical and life-saving seal hunting starting in October-November. Winter spans from October to early May with potential far northern temperatures plunging even 20 degrees within one hour especially with high arctic winds.

 

Play-fighting between the cubs and pouncing on their mother build their physical readiness to defend themselves.  What looks like carefree fun and games in polar bear cub play is the initial training the mother encourages to develop their instincts and reflexes to anticipate potential dangers from any direction. Each cub will try to assert their dominance.

 

Since polar bears are descended from grizzly bears they can mate with grizzly bears and produce a hybrid offspring recognized as a 

Grolar(Male Grizzly + Female Polar Bear) or Prizzly(Polar Bear male + Female Grizzly).  These cubs often have lighter blonde coloration and/or white and brown fur patches.  They tend to be smaller in size than their parents.  The Churchill Hudson Bay area is the only area in the world that has polar bears, grizzly bears and black bears.