They may be graceful swimmers, but penguins are hardly the most elegant walkers in the animal kingdom, and often appear as though they haven’t quite grasped the art of pedestrian propulsion. However, comical as the classic penguin waddle may be, a new study has revealed that the seabirds’ characteristic bumbling gait is in fact beneficial when walking at high speeds, allowing them to increase velocity without expending too much energy.
Though more at home on ice, the penguins involved in this study were trained to walk on a treadmill, enabling a group of researchers to monitor how their body movements changed along three different axes as speed was increased. A report of the experiment can be found in the Journal of Theoretical Biology, and describes how the researchers paid close attention to variables such as stride frequency and waddling amplitude.
A total of eight king penguins, native to the Crozet Archipelago off the coast of Antarctica, were trained to walk on treadmills. Since king penguins have an upright bipedal walk, they were considered the perfect candidates for this experiment.
Despite early difficulties getting their subjects to use the treadmills, the researchers noted that, once they became used to the equipment, the penguins were able to walk at a number of different speeds, with their maximum velocity being 2.7 kilometers per hour (1.7 mph).
According to the study authors, “waddling amplitude was strongly related to walking speed,” suggesting that changes to the depth of penguins’ “side-to-side motion is apparently crucial to speed alterations.” In other words, waddling more helps them to walk faster.
This increase in waddle depth was caused by the penguins taking longer and wider strides as their pace increased. These strides also became more frequent as the birds hurried their step, reaching a maximum of 85 strides per minute when traveling at full speed.
In light of this information, the study authors conclude that increasing their waddle enables penguins to take longer and wider steps, thereby providing greater stability as they accelerate and reducing the amount of energy needed to travel at high velocities (in penguin terms).
Since penguins often nest far from the water’s edge, fishing trips can involve a great deal of walking, sometimes requiring them to waddle for over 250 kilometers (155 miles). Even with their unique penguin plod, these journeys can take several days, and are often full of hilarity and mischief.