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Introduction
In this post, we will be talking about how polar bears survive in the cold!
DID YOU KNOW?
Polar bears have black skin
under their thick white fur polar bears have jet black skin
their fur is also translucent, and appears white under sunlight
Male polar bears can weigh as much as 10 men
800kg; twice the weight of female polar bears
polar bears are the largest species of bears and the largest land carnivores in the world
Polar bears face more threats than climate change
cause: oil and gas industry (oil exploration work)
Contact with oil spills - reduce the insulating effect of a bear’s fur, requiring them to use more energy to get warm, can poison them if ingested
So.... how cold do polar bears live in?
Polar bears can be found throughout the Arctic in the United States (Alaska), Canada, Russia, Denmark (Greenland), and Norway. Thanks to special adaptations, such as a thick layer of blubber, two layers of fur, compact ears, and a small tail, polar bears can withstand temperatures as low as -50° Fahrenheit
Polar bear fur:
no white pigment
It looks white only because the air spaces in each hair scatter light of all colors.
The color white becomes visible to our eyes when an object reflects back all of the visible wavelengths of light, rather than absorbing some of the wavelengths.
hollow fur
Trap warm air against their bodies
double-layered to insulate them from cold air
Thick, fuzzy layer next to their skin (like the feeling of wearing a wooly sweater)
Guard hairs (like a raincoat)
Keep them warm even at -40 degrees
their white fur helps camouflage into the environment
Like snow drift
Blubber - thick layer of polar bear fat
also found in penguins, whales, seals and dolphins
stores energy, insulates heat, and increases buoyancy
found just below the skin and is widely used in the Arctic region as a source of fat
also used to make oils
The ability of blubber to use these stored nutrients ensures that marine mammals are not forced to search for food for long periods of time
The blubber includes:
both proteins (mostly collagen) and fats (mostly lipids)
blood vessels in blubber constrict, or get smaller, in cold water. Constricted blood vessels reduce the flow of blood, thus reducing the energy required to heat the body, conserving heat.
Sources
https://www.wwf.org.uk/learn/fascinating-facts/polar-bears
https://www.loc.gov/everyday-mysteries/zoology/item/is-a-polar-bears-fur-transparent/
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