Penguins are typical sea birds. Although they have a bird's head, beak, and two wings, they cannot fly. On the contrary, it jumps like a fish as soon as it enters the sea, and can gallop through the water at a speed of 18 kilometers per hour. Why do penguins have wings but can't fly?From the origin of penguins, scientists have pointed out that there are pygodromes on penguins. The ancestors of bir...More