The penguins we see at the zoo today are distinctively different from many other birds due to their lack of ability to fly. Although, is flight something that can only be achieved in the air? Penguins might not be able to fly majestically as the bald eagle in the skies, but they’re capable of doing such under the sea.
Most species of flightless birds, including penguins, can be traced back to their ancestors, who were able to fly. Studies from fossils show that the early lineages of penguins had feathered wings and were gifted with the ability of flight. Unfortunately, as time elapsed and the Earth’s environment changed, penguins lost flight. In return, they developed aquatic abilities (i.e. swimming, diving deep underwater, etc.) as they adapted to their new wet environments of the southern hemisphere.
On land, a penguin’s “wings” and tail is used to maintain balance for their upright stance. Yet again, the moment they enter the water, their wings turn into power flippers allowing them to swiftly maneuver around. Surprisingly, the swimming motion penguins make closely resembles the flapping motion of birds when they fly. To increase the maximum output of thrust, they twist their flippers as they push down on the water; this motion can also be seen in fruit flies and many other insects. Additionally, like how the peregrine falcon repositions its body during a hunting dive to reach maximum speed, the penguins lower their heads when they swim so their body creates less drag.
A penguins flippers are very similar to the wings of planes. Even though their small flippers prevents them from flying, it allows them to be agile. If penguins were to have a large wing span, they will not be swift enough to evade their predators. This idea is similar as to why fighter jets are intentionally made with small wings, causing it to be unstable.