There are no penguins in the Arctic (north pole) but there are polar bears. Conversely, there are no polar bears in the Antarctic (south pole) where the penguins live. Here's a story that explains why there are no polar bears in the Antarctic!
Why aren't there polar bears in Antarctica?
Most bears live in the Northern Hemisphere; polar bears are no exception.
The Arctic and Antarctica, while similar habitats in some ways, are home to very different creatures. Both poles host a variety of seal and whale species, but only the Arctic is home to Earth's largest bear, the polar bear.
Polar bears (Ursus maritimus) and their tumbly cubs can be found around the Arctic Circle in Alaska, Canada, Greenland (part of Denmark), Norway, Russia and, occasionally, Iceland. A polar bear's fur is specially suited for temperatures that can dip below minus 22 degrees Fahrenheit (minus 30 degrees Celsius). They live on ice for most of their lives, feeding on fat-rich seals that keep them energized for long periods between meals.
Antarctica also has sea ice, cold temperatures and seals. So why aren't there any polar bears on the southernmost continent? The answer has to do with evolution and the geologic history of Earth.
"Bears are largely a Northern Hemisphere phenomenon," said Andrew Derocher, a professor of biological sciences at the University of Alberta in Canada who has studied polar bears for nearly 40 years. Aside from the Andean bear (Tremarctos ornatus) of South America, bears appear only in the Northern Hemisphere. There's no specific reason for this, just that some species evolve in some places and some don't. "Biogeography is full of oddities," Derocher said. "Some species made it to new places and some didn't."
For polar bears specifically, there was never a time in their evolutionary history when the North and South poles were connected by ice (or land, for that matter). People say polar bears are the "biggest terrestrial carnivore in the world, and yet they're not a terrestrial species at all," Derocher told Live Science. The big, white bears live on sea ice for almost their entire lives, only occasionally coming ashore to breed.
Polar bears are, evolutionarily, a relatively young species. They evolved from a common ancestor of the brown bear (Ursus arctos) sometime between 5 million and 500,000 years ago, Derocher said. But even 5 million years ago, the continents were in similar positions to where they are today, so polar bears never got the opportunity to travel from pole to pole. The closest landmass to Antarctica is the southern tip of South America, which includes Chile and Argentina. To get to Antarctica, polar bears would have to cross the treacherous Drake Passage. The area is also known for powerful storms and rough seas as cold water from the south runs into warm water from the north.
Originally published on Live Science.
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