Polar bear reproduction
Spring: Mating
Adult polar bears are solitary, but not anti-social -- they actively seek mating partners in the late spring and early summer.
Males seek out females by following their scent. Two males may fight over a female.
Polar bears couples are only together for about a week before they separate. The male may then seek out another mate (a behaviour known as polygyny) .
Males seek out females by following their scent. Two males may fight over a female.
Polar bears couples are only together for about a week before they separate. The male may then seek out another mate (a behaviour known as polygyny) .
Polar bear mating habits
- Females begin to mate around the ages of 4 or 5
- Males take longer to mature and usually begin attempts to mate around the age of 5 or 6, though their prime breeding years begin around age 10
Polar bears (Ursus maritimus)
Summer: Fasting
Food can be scarce for polar bears in the arctic summer.
Some bears follow the ice--and seals--north. But where polar bears are forced to spend the summer onshore due to lack of sea ice, pregnant polar bears may live off fat reserves for up to 9 months.
Summer sea ice is disappearing. It is projected to be nearly gone by 2040.
Some bears follow the ice--and seals--north. But where polar bears are forced to spend the summer onshore due to lack of sea ice, pregnant polar bears may live off fat reserves for up to 9 months.
Summer sea ice is disappearing. It is projected to be nearly gone by 2040.
POLAR BEARS IN PERIL: The U.S. Geological Survey forecasts that two-thirds of the world's polar bears will disappear by 2050, based on moderate projections for the shrinking of summer sea ice caused by global warming.
Autumn: Building a den
In most areas, pregnant polar bears dig dens deep in snow drifts - on land or on the sea ice - where they will wait to give birth during the winter. In Canada, they build dens in frozen peat banks.
Expectant mothers use these dens to rest and keep warm during the harsh Arctic winters.
Expectant mothers use these dens to rest and keep warm during the harsh Arctic winters.
Polar bear den opening near the Alaska coast.
Winter: Raising cubs
After two months or so in the den - usually between December and January - a mother welcomes cubs into her den.
Between the snow den, their mother's body heat and milk, the cubs grow fast before they leave the den in March or April.
The cubs take short field trips from the den to get used to outside temperatures before learning to live and hunt on the frozen ocean.
After 2 years together, the family disperses and the cycle begins again.
Between the snow den, their mother's body heat and milk, the cubs grow fast before they leave the den in March or April.
The cubs take short field trips from the den to get used to outside temperatures before learning to live and hunt on the frozen ocean.
After 2 years together, the family disperses and the cycle begins again.
