Penguins waddle, and hop on land. Though they glide through water with the greatest of ease, penguins on land are ungainly creatures. Indeed, when it comes to walking, penguins expend twice as much energy as any other terrestrial animal of the same size. Their distinctive waddle, however, is not to blame.
According to research published today in the journal Nature, this graceless gait is the most efficient way for penguins to move around on terra firma. It is found is that they are inefficient because of their short legs and big feet, and waddling is a means to cut their losses.