Saturday, October 3, 2009

Why are flamingos pink?

Flamingos are known for their brightly colored pink feathers, but the truth is, they are actually born white. But how does this happen? After all, unless you're Micheal Jackson or a chameleon, you must learn to live with the skin, feather, fur, or scale color you are born with. But flamingos have options. If they don't fancy their white feathers, they can simply eat themselves pink, giving a whole new meaning to the phrase, "you are what you eat."

According to Cecil Adams of the website The Straight Dope, flamingos eat a diet high in carotenoid compounds. The most well known of such compounds is probably Beta Carotene, which is found in a variety of vegetables including carrots. "Carotenoids tend to be a persistent red orange in color," explains Adams. "Depending on formulation, they impart a red, pink, orange, yellow, or even green cast to some plants and to the higher links in the food chain by which those plants are consumed."

Though it is unlikely to see a flamingo snacking on a carotenoid packed broccoli stock or a carrot, flamingos are big fans of brine shrimp, and brine shrimp are big fans of algae, which contains carotenoids. In short, the shrimp act as carotenoid carriers for flamingos. Catherine Side explains on the African Conservation Foundation website that when flamingos ingest shrimp the carotenoid chemicals, "are not broken down and have extremely low water solubility, [so] they are deposited in the feathers of flamingos."

So what happens when flamingos don't get their recommended dose of carotenoids? They turn white. R.P Dales of the University of London explains on the African Conservation Website, that when the birds shed their feathers (a habit known as moulting), they shed the pink pigment also, so if that pigment is not replenished via carotenoid consumption, the flamingos will become pale.

Interestingly enough, flamingos are not the only animals whose hue comes from their food. "The pink color of some other birds, such as spoonbills and the pink ibis, is also due to carotenoids," says Dales. In addition, Adams points out that, "Salmon caught in the wild are orange because of their diet of crustaceans that contain carotenoid. The flesh of farm-raised salmon, which don't feed on crustaceans, is an unappetizing gray unless the fish are given the carotenoid astaxanthin."

So are human skin pigments affected by carotenoids? According to Adams, they certainly can be. "If [humans] eat enough carrots (which, duh, contain carotene), they'll turn orange," he says. "And if they have no interest in eating vegetables but would still like to be orange, they can take beta carotene pills providing 10 to 30 times the normal dietary amount."

1 comment:

  1. Ashleigh, well-written and informative. I did have one question: would all birds with light feathers turn pink if they followed the flamingo's diet? Or is there something about the flamingo's feathers that works in tandem with diet to turn the bird pink? If the latter, I wonder what the evolutionary benefit is?