What makes Polar bears prefer the cold as opposed to other bears?
In: Biology
Since everyone is mentioning white fur: polar bear fur is actually clear, the structure is what makes it reflect light in the way it does to make it look white (similar to blue jays reflecting light to look blue).
Other bears not being around.
By being adapted to the cold, polar bears can live where other bears (and other large predators) cannot. They get the arctic all to themselves and don’t have to compete with other species for food.
Predators goes where the food are.
Predators that have think white fur have an easier time hunting in the areas than a brown one.
A genetic mutation of the fur colour gene of a brown bear was the “first” polar bear. The white fured bear was better adapted to the white envoirment and mated, passing on the white fur genes more succesfully than the brown counterparts.
With the succes the polar bears could venture futher north to rich hunting grounds seperating them from the normal brown bear population, small adaptations like a larger body and more enlongated snout where favored and thus those traits slowly dominated.
However, the 2 specieses are not that far apart and can still interbred, and more and more brown-polarbear mating is occuring as the ice melts and the polar bears are going further south.
As it stands now, it looks grim for the polar bears as they cant adapt fast enough to the chaging climate and could become an endanger species realitively quick. – The new hybrid species are on the rise though, but the general bear population is in rapid decline 🙁
Really good answers above. In short, like most creatures in nature, it’s not _preference_, it’s the prospect of a rich, unexploited niche that drives the creature to occupy it and adapt for it.
It’s not the cold so much as the coastline.
They’re well optimized for hunting in the Arctic – they’re the apex predator of the far north and rarely eat any plants.
The coloration is obvious, but they also have special water-wicking fur to keep them dry and warm even when they’re soaking wet. They’re skilled swimmers and powerful hunters.
That makes them great predators for the frozen coasts, but these advantages disappear when you head into the inland pine forests.
On land, the supply of seals drops to zero and the more omnivorous lifestyle of the grizzly bear is more successful.
They slowly evolved to hunt and live in colder and colder conditions.
You look back at a time before polar bears. You have the vast Arctic with a whole bunch of uneaten seals. Just below the Arctic, you have some populations of grizzlies that are starving due to competition for moose meat.
Over time, the grizzlies with slightly longer fur can survive further north and access the seal reserves. The grizzlies that can’t go further north have to compete with grizzlies from below the Arctic.
Over time, some grizzlies begin to live primarily in the Arctic. They develop white fur, longer necks, more insulation and such. Boom, now you have polar bears.
Now, polar bears are suited to live in the Arctic, and are uncomfortably hot anywhere else.
As stated before fur is clear and hollow.
And it wasn’t one mutation where a bear was all of a sudden white. A lighter fur bear along with his other bear mates was able to hunt and not be seen as easy. The darker bears couldn’t survive and thevlighter bear thrived and survived to pass
on its genes. Slowly over time the lighter colored bears could continue to expand into untapped hunting grounds.
Where as darker bears couldn’t prosper.
Lighter and lighter over generations the Polar Bear survives and slowly turns white due to being able adapt to its environment.
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