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　　Because wild penguins only live in the colder parts of the southern hemisphere, most people have never visited them in their natural habitat. However, one can’t help but burst into laughter at the sight of these black and white bowling pins shuffling side to side across the ice on their impossibly short legs. The funniest feature of the penguin is, no doubt, its walk, or“waddle.”But it is this waddle that allows penguins to tolerate their bitterly cold habitat.

　　Scientists have long known that penguins need a lot of energy to keep moving. To waddle a given distance, penguins use twice as much energy as other creatures of the same size use to walk equally far. However, in order to survive in their harsh habitat, penguins must save as much energy as possible. Some people might wonder why the birds don’t simply stop waddling and walk at a slower pace. Surprisingly, the penguins’walk allows them to save energy that would be wasted if they walked without waddling.