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Polar Bears of Hudson Bay

Polar Bears of Hudson Bay - Churchill Northern Studies Centre - Subarctic Research - Churchill Manitoba

Introduction

Discrete populations of polar bears are found throughout ice-covered waters of the circumpolar Arctic. In Canada, there are 13 populations, totaling approximately 15, 000 bears. Polar bears are largely marine animals, preferring to remain on the sea ice where they hunt their main prey of seals. They feed primarily on ringed seals although bears will also eat bearded seals and occasionally walruses, beluga whales and narwhals. In many areas of the arctic, they are able to hunt on the ice year-round. It is only in areas where the ice melts in the summer, like southwestern Hudson Bay, that the bears are forced ashore until the ice refreezes in the fall.

Learn more about the CNSC Lords of the Arctic: Polar Bear Learning Vacation.

Interesting Facts

  • "Arctic" is the Greek word for bear
  • "Nanuk" is the Inuit word for polar bear
  • Polar bear fur is white but their skin is black
  • Polar bears have huge, webbed feet--their feet act as oars when swimming and as snowshoes when walking across thin ice
  • Unlike black and brown bears, polar bears are not territorial

Questions and Answers about Churchill's Polar Bears

Why is Churchill the best place in the world to view polar bears?

The Churchill area lies near the southern limit of where polar bears are able to live year-round. The Churchill region also has one of the biggest polar bear denning areas in the world. The ice throughout Hudson Bay melts completely by the end of July or early August and does not refreeze until approximately early November. This means that all bears must come ashore for about 3-4 months. During this period of time, the bears are not actively hunting, therefore they must survive on fat reserves that they have built up through the winter.

The ice first forms along the western coast of Hudson Bay, and usually runs north along the coast from Cape Churchill. Throughout the fall and especially just before freeze-up of the bay, increasing numbers of bears move towards the coast. Here, they congregate within easy viewing access, until they can move out onto the frozen ice of the bay and begin feeding again for the next eight months.

Sparring behaviour between males is observed at this time, and it is curious to note that females do not initiate this behaviour. Our EarthWatch program led by University of Central Florida researchers Jane Waterman and Jim Roth studies this social interaction and also how ecotourism affects male polar bears.

Learning Vacation - Churchill Northern Studies Centre - Subarctic Research - Churchill Manitoba

Learning Vacations

Discover more about polar bears on an exciting learning vacation!

When is the best time to see polar bears in the Churchill region?

There is no predictable peak viewing time since congregation of the population depends on ice formation. This period can vary from early October to mid-December. Generally, you should be able to see polar bears throughout the months of October and November but there is never any guarantee!

During October and November, several polar bear viewing tours, including Tundra Buggy Tours and Great White Bear Tours, operate out of Churchill. Nature First Tours and Transportation also provides walking tour services during the arctic summer and in 'Polar Bear' season. The Churchill Northern Studies Centre offers both Elderhostel Lords of the North programs and our own CNSC Learning Vacation polar bear courses.

What do Churchill's polar bears do during the summer?

During the summer, bears eat very little and tend to laze around to conserve energy until they can hunt again. This is known as a "walking hibernation." The population is scattered along the coast during the summer, and bears are only occasionally seen in the town of Churchill. The bears do not come together until the fall during their congregation at Cape Churchill.

How big are Polar Bears?

Polar bears are the largest land carnivores in the world! An average adult male weighs 500 to 600 kg (1100 to 1300 lbs) and reaches maximum size by age 8 to 10. An average adult female is about half the size of a male, weighing 200 to 300 kg (450 to 650 lbs) and reaching maximum size by age 4 to 5. Cubs weigh only 0.6 kg (about 1 lb) at birth--that's about 15% of the weight of a new-born human baby

What is the life cycle of a polar bear?

Both males and females become mature at 4 to 5 years (although most males probably do not breed until 8 to 10 years.) Polar bears mate out on the sea ice in the spring (April/May). Fertilized eggs do not implant until September or October. Instead of returning to the ice in the fall to hunt with the rest of the population, pregnant females enter a maternity den by late October/early November and cubs are born in the den from late November to early January. Twins are most common (60-70%) although a mother may have 1 to 4 cubs in a litter. The new family moves out of the den in late February to hunt--the same time that seal pups are born. This means that pregnant females go about 8 months without eating seals, during which time they also give birth and nurse their cubs. This is one of the longest fasting periods of any mammal.

In most areas, cubs remain with their mother for 2.5 years although occasionally they may stay for 3.5 years. In western Hudson Bay, cubs can become independent at only 1.5 years. In wild populations, lifespan for males is over 20 years and for females over 25 years.

An excellent book on Polar Bears is "Polar Bears" (written by Ian Stirling with photographs by Dan Guravich.)

All researchers and visitors to the Churhill Northern Studies Centre must adhere to our Polar Bear Safety policies.

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