Flamingo

The pink comes from food

Flamingo chicks hatch gray or white. Their distinctive pink-orange color develops over the first few years of life from carotenoid pigments in their food — tiny crustaceans (like brine shrimp) and blue-green algae they filter from saline waters. Captive flamingos fed an artificial diet without these pigments fade to white, which is why zoos add carotenoid supplements to their food.

The exact shade varies by population and species:

• Greater flamingo (Old World) — palest pink with vivid pink-and-black wings.
• Lesser flamingo (Africa, India) — deeper pink overall.
• Caribbean flamingo — the brightest, intense salmon-pink.
• Andean and James’s flamingos — pale pink with yellow legs.
• Chilean flamingo — pink with grey legs and red joints.

Filter feeding upside-down

A flamingo’s bill is a filtering apparatus held upside-down in the water as it walks. The bird sweeps its head side to side while rapidly pumping its tongue, which creates suction that pulls water through fine comb-like plates (lamellae) inside the bill. The lamellae trap algae, brine shrimp, and other small organisms while expelling water and silt — the same fundamental approach as a baleen whale, scaled down.

Standing on one leg

Flamingos famously sleep and rest on a single leg. The reason was debated for years; recent research suggests two factors:

• Heat conservation — standing on one leg reduces contact with cold water, halving the surface area through which heat is lost.
• Skeletal locking — flamingos have a passive joint-locking mechanism that requires no muscular effort to hold the position. Standing on one leg is actually more energetically efficient than standing on two for them.

A breeding crowd

Flamingos breed in massive colonies of tens of thousands, sometimes a million or more birds. Their nests are conical mounds of mud they build in shallow water, with a single egg laid on top. Both parents produce a special “crop milk” — a high-fat, protein-rich red liquid secreted from the upper digestive tract — to feed the chicks for up to two months.

Salt and alkaline lakes

Most flamingo populations specialize in extreme salt or alkaline lakes that exclude most other species. Lake Natron in Tanzania, with caustic alkaline water that can burn most animals, is the breeding ground for over a million Lesser flamingos — a near-monopoly habitat with abundant food and few predators.