Have you ever seen penguins and polar bears together? Yes!—on Christmas cards and advertisements. In the real world, however, it just doesn’t happen—polar bears live in the Arctic and penguins are found almost exclusively in the Southern Hemisphere. Still, a lot of birds migrate annually between the two hemispheres, and some penguin species are known to range over long distances between breeding seasons: why haven’t penguins discovered the seemingly perfect environment of the Arctic?
Penguins range too far south.
Only a few penguins live in the warmer parts of the southern oceans. The Galapagos Penguin, breeding in the Galapagos region, may even breed a little north of the equator, and the Jackass Penguin (or African Penguin) may range as far north as the equator. These penguins have special ways of keeping cool and live in places where cold ocean currents cool the immediate environment—the Humboldt Current in the eastern Pacific, and the Benguela and Agulhas Currents off South Africa. They are non-migratory species, so they’re not likely to stray too far north.
Most other species never come further north than 45°S latitude. Specially adapted for life in cold places, they don’t wander into warm water.
Equatorial waters are too hot for penguins
Most penguins are built to stay warm in extreme cold, a necessity for a bird that lives in the frigid and windy Southern Ocean (see How Do Penguins Keep Warm?). The ability to live in the coldest place on Earth comes with a trade-off however: they’re not very good at shedding extra heat. Penguins don’t migrate to the North Pole simply because they can’t get there. The vast reaches of ocean between 45°S latitude and the northern Atlantic and Pacific are too hot for them.
Penguins don’t live with polar bears
Penguins are fabulous swimmers but they’re rather slow and awkward on land. Nonetheless, they spend considerable lengths of time on land during the breeding season, remaining for long periods in the colony. Fortunately, there are few predators on the southern islands or the beaches and ice of Antarctica. In the north, it would be different—in the north, there are Polar Bears, Arctic Foxes and other predators, including people. Any penguin colony that started up in the Arctic would likely quickly fall prey to these carnivores. Indeed, the few human attempts to establish penguin colonies in the Arctic have all failed.
North Pole penguins
There are occasional sightings of penguins in the northern Pacific, and penguins have been hauled aboard fishing boats in nets from time to time. Scientists believe that these birds came to the north as a result of a similar mishap—accidentally plucked from the ocean in the south, they are sometimes kept aboard boats for the amusement of the crew and eventually released far from home. If these penguins arrive in the Arctic, they will never get home for the same reasons they couldn’t have migrated there naturally. The water in between is too hot.
From http://bird-habitats.suite101.com/article.cfm/north_pole_penguin
