On land, penguins are ungainly, they can’t fly and they can barely waddle around on their short legs. Yet they are one of the most successful marine species on the planet. Seventeen species of penguin survive in the wild and colonies of up to five million strong. On land, penguins would starve, there is nothing there but snow and ice. But Antarctica is surrounded by an ice cold ocean that is teaming with life. So penguins have conquered their environment by taking to the sea.

They swim well enough to catch all of the fish and crustaceans that they need. In fact they can consume enough fish to last them through their breeding season, during which the males will not eat for a hundred days. When penguins leave their land an almost magical transformation takes place, the penguin turns from a flightless bird into a formidable swimming machine speeding through the water at twenty miles per hour.

Their bodies have this thick layer of fat that keeps them warm. The waterproof feathers lie flat on a streamlined body, the webbed feet become rudders and the wings turn into powerful flippers. They also have heavy bones that allow them to stay underwater. Unlike a bird in flight, a penguin is supported by the water and does not need vertical lift. The penguin can angle its wings on each stroke to maximize the forward thrust. It surges through the water like our greatest champion swimmers, only better. Another great adaptation that they have developed is their coloring. Their back is black and their front white. When underwater, predators from above are looking at their black back and it is difficult to see them. Predators from below find it hard to spot their white underside against the light.