Penguins are notoriously inefficient walkers, expending twice as much energy in walking a given distance as any other animal of the same weight.
But don't blame it on their funny, waddling gait.
A new study by researchers at the University of California, Berkeley, shows that waddling actually helps penguins conserve energy. The real problem is their short legs.
"Our findings indicate that walking is expensive for penguins not because of their waddling, but because they have such short legs that require their leg muscles to generate force very quickly when they walk," said Timothy Griffin, an integrative biology graduate student in UC Berkeley's College of Letters & Science. "When we compare penguins to animals with similar leg lengths, they burn about the same amount of calories per unit mass."
Griffin and Rodger Kram, a former assistant professor of integrative biology at UC Berkeley, report their findings in the Dec. 21/28 issue of the journal Nature. Kram is now in the Department of Kinesiology and Applied Physiology at the University of Colorado, Boulder.
The results have implications not only for the ecology and evolution of penguins, but for waddling behavior in other animals, and maybe even pregnant women.
"Our knowledge gained from penguins provides novel insight into the gait mechanics of humans with increased lateral movements, such as in pregnant women or obese individuals," Griffin said. "This information may lead to improved understanding, evaluation and treatment of individuals with gait disabilities."
Griffin and Kram performed their experiments on Emperor penguins at San Diego Sea World's "Penguin Encounter" exhibit, a large refrigerated penguin city housing some half dozen penguin species. With the help of Sea World staff, the UC Berkeley scientists and their student team nudged the naturally curious penguins across a force platform to measure the side-to-side and fore-and-aft forces they exert while walking
Contact: Robert Sanders
University of California - Berkeley