The animal that only eats upside down is the flamingo. Flamingos are well-known for their habit of eating with their head upside-down, which is largely due to the structure of their mouth and the logistics of lowering their long, graceful neck into the water. Flamingos feed by sucking water and mud in at the front of the bill and then pumping it out again at the sides. Here, briny plates called lamellae act like tiny filters, trapping shrimp and other small water creatures for the flamingo to eat. Because the flamingo must use its beak in an upside-down manner, the beak has evolved to reflect this. The flamingo’s top beak functions like the bottom beak of most birds, and vice versa.