Have you ever wondered why flamingos are pink or orange? Flamingos are pink or orange or white because of what they eat. Flamingos eat algae and crustaceans that have pigments called carotenoids. These pigments are actually found in the brine shrimp and blue-green algae that the birds eat.
Enzymes in the flamingos’ liver break down the carotenoids into the pink and orange pigment molecules deposited in their feathers, bill, and legs. Flamingos that eat mostly algae are more deeply colored than the birds that eat the small animals that feed off of algae. Captive flamingos are given a special diet that includes prawns (a pigmented crustacean) or additives such as beta-carotene or canthaxanthin, otherwise they would be white or pale pink.
Young flamingos have gray plumage which changes color according to their diet.
People eat foods containing carotenoids, too. Examples would include beta-carotene in carrots and lycopene in watermelon, but most people do not eat enough of these compounds to affect their skin color.