The origin of the beloved penguin waddle begins with the extinction of the dinosaurs, which killed most oceanic predators like sharks and reptiles. This allowed certain birds to dive into the water for food, and over generations their wings turned to strong flippers, their legs shrunk, and they became flightless. Eventually, their bird-like horizontal posture gave way to a vertical “standing” waddle that we recognize today.
The penguin has several fossilized prehistoric ancestors that could provide more answers. Scientists have been studying fossils such as the aptly named “colossus penguin,” which stood as tall as a person. Another, the Waimanu, was a penguin-like creature that had a horizontal posture and wandered New Zealand sixty million years ago.
At first the penguin's waddle appears clumsy or inefficient, but their gait only tells half the story. A 2000 study found that rocking back and forth actually saves penguins precious energy needed to walk long distances. By swinging their weight back and forth, they are able to conserve eighty percent of the energy they use with each stride - one of the highest of all animals.
A 2015 study at the London Zoo aims to find out exactly how their legs accomplish this without walking like other animals. A team of scientists, led by John Hutchinson, measured the gait of a colony of penguins by using a walkway with metal plates that measure the force of each step. Using this information along with video recordings, they hope to find out more about the penguin’s mechanics.
Fun fact: some of the penguins in this experimental colony have adorable names such as Pickle, Summer, Dingle, Harlequin, Carnaby, and Rocky the Rockhopper.