penguins

Just to let everyone know that penguins are a group of flightless birds found in the southern hemisphere. They inhabit all latitudes, from the tropical Galapagos islands to the frozen wastes of the Antarctic; the emperor penguin (the largest species at up to 1.1m tall) breeds on the Antarctic pack ice, while the royal penguin and the king penguin breed on sub-Antarctic islands. In contrast, the little penguin, or fairy penguin, which stands at just 40cm, is found around the coasts of Australia and New Zealand.

Penguins are superb swimmers; they have lost the use of their wings for flight and these have instead become flippers, which enable them to move at high speeds underwater in pursuit of their fish prey.

Can anyone tell me why penguins have black backs and white bellies?