World Penguin Day, which falls on April 25, is a day to recognize a unique set of inhabitants of the earth. There are 18 species of the flightless birds on the planet, every single one originating in the Southern Hemisphere. Adapted for a life in the ocean, the birds have counter-shaded dark and white plumage and flippers for swimming. Most of them feed on krill, fish, squid, and other forms of sea life which they...