Why are flamingos pink?

Here is a fact that surprises almost everyone: flamingos are not born pink. Their chicks are grey or whitish, and the characteristic pink color appears little by little, over the years. The reason is not in their genes, but on their plate.

The secret is in the food

The pink or reddish color of flamingos comes from pigments called carotenoids (the same kind of compound that gives carrots their color). As Wikipedia notes, these pigments arrive through their diet and, once digested by enzymes, are deposited in the feathers, skin and beak. Where do they get them? Mainly from:

• Microscopic algae, especially the blue-green ones rich in pigment.
• Tiny crustaceans, such as brine shrimp (artemia).
• Other plankton abundant in the salty lagoons where they live.

The more pigment their food contains, the more intense the pink. In fact, flamingos that feed directly on those algae tend to show a brighter color than those that get them indirectly.

Why the chicks are grey

A newborn flamingo has not yet accumulated carotenoids, so its down is grey. The pink builds up as it grows and eats: it can take two to three years to acquire the full adult plumage. It is, literally, a color earned by eating.

A telling example happens in zoos: captive flamingos, if they do not receive pigment-rich algae or crustaceans, tend to fade. That is why many zoos add carotenoid supplements to their diet so they keep the pink the public expects to see.

A beak designed to filter

How do they gather so much algae and crustaceans? With a curious method. The flamingo puts its head in the water almost upside down and uses its curved beak, fitted with fine plates called lamellae, like a sieve: it pumps water and mud with its tongue and retains the edible particles while expelling the rest. It is a filtering system similar, in principle, to that of whales.

Pink also seduces

The color is not just a side effect of the diet: it is also a signal. As EL PAÍS explains, a deeply pink flamingo is advertising that it eats well and is in good health, which makes it more attractive when it comes to mating. It has even been observed that, during courtship, some flamingos “put on makeup,” spreading pigmented secretions over their feathers with their beak to look more vivid. In their world, pink means a good catch.

You are what you eat (and they wear it)

Flamingos are the most striking proof that diet shows on the outside. They are not born pink, nor are they pink out of genetic whim: they build their color, feather by feather, with the pigments of the algae and crustaceans of their lagoons. Next time you see that pink patch reflected in the water, you will know you are really looking at a menu well used.