Terrestrial locomotion in penguins: it costs more to waddle.
The energetic cost for walking is relatively higher for penguins than for other birds or for quadrupeds of similar body mass. The morphology of penguins seems to represent a compromise between aquatic and terrestrial locomotion wherein both energy economy and speed suffer when the birds move on land.
D000818:Animals; D001717:Birds / Q000378:metabolism / Q000502:physiology*; D001835:Body Weight; D004734:Energy Metabolism; D008124:Locomotion; D010101:Oxygen Consumption