The pink coloration of the flamingos is actually caused by the carotenoids contained in their diet. If their food is rich in carotenoids, they might even get crimson. And speaking of their food, mainly shellfish and algae, flamingos have quite a strange way of feeding -- they can only eat with their heads upside down; this is the only way that they can use their special filtering beaks. The filtering is assisted by hairy structures called lamellae. An average flamingo can filter as many as 20 beakfuls of water in a second.