Why do penguins waddle?

Penguins waddle because of their upright posture and unique body structure. Their legs are short and positioned at the back of their bodies, which makes walking in a straight line difficult. As a result, they sway from side to side to maintain balance. This waddling gait is energy-efficient on land, where penguins spend a lot of time navigating icy terrain. Penguins also use their flippers to maintain balance and help with movement on land and when swimming.