Because a polar bear would eat the little penguins
Some might say the environment is different in the North Pole but there are no frogs in places (e.g. On remote tropical islands) that are perfect for frogs.
The reason might be that penguins evolved in the Southern Hemisphere and could not migrate up to the North Pole because the tropics are a natural barrier to them. It's the same reason, I think, there are no frogs on tropical islands where frogs could not migrate to because of the salty seas.
Because they enjoy the people in the south better they all get hunted in the north
Distance. Polar bears occur in the north pole and they simply don't walk or swim through the tropics. They don't range very far south. Penguins range up into Africa and S. America, but they don't range into the northern regions. I suspect if you transplanted a polar bear to the south pole, they would do great.
The magnetic pull from the north and south cause the brainwaves of these two animals to be divided. Penguins primarily are on the south pole because genetically, they fell the pull of the south pole. Polar bears feel a pull in the other direction - the north pole, thus they reside in that area. If you look at Zoos and animal sanctuaries, you will notice that the Polar Bears will always be pointing to the north and penguins to the south, due to the nature of the polar pull.. Hah. I tried to be technical, this may have false information, use this info with caution. :P
It is a good question,I think they will fight if they stay together.
Because the polar bears are afraid of the penguins so they stay far apart as possible
Because the penguins payed 5.6 million euros to the polar bear in court to make them stay north
Because at the South pole the penguins have real land to breed on and the polar bears prefer to breed on pack ice.