Emperor penguins belly-flopping out of the water, Antarctica (© Frans Lanting/Getty Images)

【January 20 2013】Unlike most other birds, penguins can't fly. But they make up for that by swimming like champs. Just as other birds are aerodynamically shaped, penguins are aquadynamic, able to glide through water thanks to their streamlined body shape and flipperlike wings. And while most birds have hollow bones to help them stay aloft, penguin bones grow solid as they mature into adults. The added weight of the dense bones helps the birds stay submerged as they dive into the cold Antarctic waters in search of tasty seafood. Explore breathtaking Gallery from the HuluTrip homepage over the past 5 years..