Woodpeckers

Being a life-long biologist, I am always fascinated with great examples of Darwinian evolution. Woodpeckers are perfectly evolved for taking advantage of a niche otherwise ignored—insects living in the bark of trees. First, a thick, strong bill and reinforced skull allow them to drill right into wood to excavate hidden bugs and larvae. Second, zygodactyl feet mean that two toes face forward and two back, allowing the woodpecker to grip a tree trunk and climb vertically. Finally, a heavy, reinforced tail acts as a prop to enable a vertical lifestyle!