Why are there no penguins at the North Pole and no polar bears at the South Pole?
The answer should be simple and concrete but it is not. The evolution of the species determined that polar bears (maritime ursus) do not live in Antarctica, nor penguins in the North Pole.
Polar bears are descended from the European brown bear.
Over the years it evolved into a bear (the polar bear) that could withstand the polar climate. The reason why it has not reached the southern hemisphere is that at that time large bears already lived on all continents and the polar bear (which millions of years ago was much larger than it is now according to the fossil record) then would have been competing with them.
Therefore, the geographical distribution has remained in the ecological niche where they currently live. The terrestrial tropics acted as natural barriers for both penguins and polar bears.
This is another important reason why they cannot reach or migrate to opposite poles and therefore are limited to living in the northern hemisphere and penguins in the southern hemisphere. Regarding the penguin, it is a bird and it is thought that it has a common ancestor with the pelican family. One might think that they have divided and that each covers its niche. In addition, the penguin breeds in places in the southern hemisphere where there are no predators on land, such as Antarctica and adjacent islands.
In these places there are no predators on land, so the penguin has been able to evolve in quantity and in different species. There are other places where it can breed in peace outside of Antarctica, for example New Zealand, where there are no predators on land either. The penguin is a very vulnerable animal since it does not know how to fly and also cannot tolerate hot sea currents, so it can only live in the southern hemisphere. In both territories (Arctic and Antarctic) it is cold and there is ice.
They are both circling the poles.
But the arctic and antarctic lands constitute very different types of
Most of the Arctic is frozen ocean, connected to surrounding land masses. Brown bears from European forests in the Northern Hemisphere probably headed for the Arctic a long time ago. Through geological ages, they adapted to their environment and were transformed by natural adaptation mechanisms into white polar bears. The Antarctic Territory, on the other hand, is a landmass surrounded by the ocean.
Penguins couldn’t have walked to Antarctica.
The ancestors of today’s penguins are thought to have possibly flown and may have flown to Antarctica. The penguins would not adapt properly if they were “transplanted to the arctic.” This is because they have special requirements to feed and reproduce. All their natural predators come from the sea, penguins would be very vulnerable in the Arctic and very easy for predators to capture. (The Arctic is ocean.)
On the other hand, if polar bears were “transplanted” to Antarctica, they might have some problems breeding females. Polar bears would feed very well on penguins and Antarctic seals since they have never known a predator that attacked by land like the bear. Due to the increase in the temperature of the planet, it has been thought of as a conservation measure, transferring polar bears to the Antarctic territory, but many scientists state that perhaps the change of habitat would be worse.
It is under discussion.