Are Polar Bears & Brown Bears Cousins?
When is a bear not a bear? When it is its cousin!
For some time now, scientists have thought that polar bears established as their own separate species only about 150,000 years ago. Earlier studies had focused mainly on mitochondrial DNA (mtDNA), which is passed from a mother to her offspring. They had concluded that polar bears were a recently evolved type of the northern brown bear and that white fur evolved in response to their arctic habitat.
Recent studies however suggest that the evolution of polar bears and brown bears as separate species occurred nearly 600,000 years ago. Axel Janke and Frank Hailer, researchers from the Biodiversity and Climate Research Center in Frankfurt, Germany compared genetic sequences from 19 polar bears, 18 brown bears and 7 black bears in a more comprehensive study.
The Sea Bear
Polar bears also known as Ursus Maritimus (Sea Bear), live along shores and on sea ice in the Arctic. There are about 20,000 to 25,000 polar bears living worldwide today. When sea ice forms over the ocean in cold weather, many polar bears head out onto the ice to hunt seals. When the warm weather causes the sea ice to melt, polar bears are forced to move back toward shore.
Polar bears, the largest among bears, are also the largest predators on land. When they hunt, they often rest silently at a seal's breathing hole in the ice, waiting for a seal in the water to surface. Once it comes up, the bear will spring and sink its jagged teeth into the seal's head.
Amazing Fur Facts
Polar bears have fur and skin that allow them to absorb sunlight for warmth. Their blubber, or fat, insulates them in cold water. Did you know that a polar bear's fur is not white? Each hair is a clear hollow tube. Polar bears look white because the hollow hair reflects the light. They have black skin under their clear fur!
On sunny days, the tubes trap the sun's infrared heat and keeps the bear warm at 98 degrees F when they're resting. Polar bear fur is oily and water repellent. The hairs don't mat when wet, allowing the polar bears to easily shake free of water and any ice that may form after swimming.
Humans are the polar bears only predator. The polar bear's habitat is under threat with man moving into the Arctic region to mine for oil and other resources. Oil spills are particularly dangerous. Besides, human activity and the accelarating threat of global warming is reducing the ice shelves that these bears have left to make their homes.
At this time polar bears are regarded as endangered and vulnerable. Countries around the world are working to protect them.
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its sad hearing about the polar bears going there great animals and really cute
Wow, that is a big bear. How are they that different from a brown bear?
Those bears are so cute.
That is really cool that polar bears are cousins to other bears. I do like that polar bears and other species of bears are related.
I want to help polar bears before they all die.
yay polar bears
I hope the polar bears can survive the fast-changing climate! I would hate for them to be extinct. The polar bear is super fascinating from their clear fur and black skin to their hunting.
I wonder how I could help
I wish there could be an easier way for them to get food.
I didnt kow that a polar bear has clear fur and black skin that absorbs heat. Good thing they dont live in Texas.
I don't want the Polar Bears all gone.I think better way to do is get all polar bears in the zoo,and get their better way to do.
polar bears are so cute!
I want to help the polar bears because without them another animal would be extinct.
There is 20,000 left I wonder whats happening to them.
That is amazing that Polar Bears our so big and a little ice when it brakes down.
I think that people should reduce globle warming
Wow that is terrible that the polar bears are also losing their food, and that they could possibly almost be extinct. I am glad though that people are helping them to survive and to protect them.
I already knew about polar bears having black skin and clear fur, but I learned other interesting facts, such as: polar bears are related to brown bears. I had always thought that all bears had developed themselves, because of their different fur coloring, but it is neat to see that they are all connected! Science is so cool!
Oh poor polar bears. They are so cute
Those Polar bears have a lot of fur to survive in the Artic.
They're just letting them go extinct ?
2000 left of such interesting aninmals that are related to black and brown bears. i wonder how they actually got apart so far away from each other and look so different but are still related
oh god polar bears are in danger too hot in this earth so the ice melts and there go the polar bear byebye:(
I thought they were their own species
Me too.
It is sad that there are very few polar bears left in the world.
there are a lot left
Thats sad :( Hope they survive!!
polar bears are kool there some alive still
i love polar bears i think their pretty big
I think they are cousins of the black bears.
It Would Be Really Sad For The Polar Bears To Go Extinct !
I love polarbears!
I really hope polar bears don't go extinct
I agree Morgan
Thats is horrible... We can't just WANT them to become extinct.. We need to do something about this!
I dont want the polar bears to go extinct but it is cool that they are related.
that is so sad
It's just like animal abuse. You can't just want them to become extinct. We have to save them guys.
I also think we should do something about it. The polar bears are living animals with feelings like you and me. If they don't have food, they could die and become extinct. Then our children wouldn't be able to see these magnificent creatures and their adorable babies.
they could be cousins.. they both are cute and we should help them stay alive and not get endangered even if their fur can be lots of money.
I never thought a brown bear and the polar bear as cousins. I always thought of them as two different bears because of where they lived.
I never knew that polar bears have black skin under their clear fur. That's really cool! I wouldn't surprise me if polar bears and black bears were actually related. They are basically the same except for different fur color and their habitat.
The thought of Polar Bears becoming extinct is horrible!
The babies were really cute. I liked how they copied their mother. The mother seems to sacrifice everything for her babies.
that would be cool if they were cousins
The polar bears are going extinct and not many people are trying to save them. Numerous are dying everyday.
I think they are
That is so sad that there are so few of these bears left in this world! We really should do something to help the endangered/going on extinct animals! :(
There is only 20,000 polar bears left!:( Us human beings need to recycle, ride your bicycle to wherever (unless if you don't have a bike or you aren't allow to) and stop GLOBAL WARMING!