How do polar bears stay warm in Arctic winters?
Polar bears have several adaptations that allow them to stay warm in the extremely cold Arctic winters:

1. Thick fur: Polar bears have a thick fur coat that provides insulation and helps keep them warm in the cold temperatures.

2. Hollow hairs: The individual hairs of a polar bear's fur are hollow, which helps trap warm air close to the bear's skin.

3. Fat reserves: Polar bears build up a thick layer of fat reserves during the summer months, which they use for energy and insulation during the winter.

4. Black skin: Although their fur is white, polar bears actually have black skin, which helps them absorb more heat from the sun.

5. Redistributed blood flow: Polar bears have a system of blood vessels and muscles that allows them to redistribute blood flow and conserve heat in their core when it is cold.

6. Denning: During the coldest parts of winter, polar bears often den in snowdrifts or in caves they dig in the snow, which helps protect them from the cold and wind.

Overall, these adaptations allow polar bears to survive and stay warm in the extreme cold of the Arctic winter. However, climate change is causing Arctic sea ice to shrink, which is making it harder for polar bears to find the food and habitat they need to survive.