Against the morphological backdrop of the rest of nature, a giant pink bird on stilts sounds like something out of Lewis Carroll’s imagination. And yet flamingos came out of evolution’s laboratory, surprising and inevitable as the neocortex, so extravagant in their improbability that a group of them is called a flamboyance.

But the flamboyance of flamingos does not come from within — it is acquired the way experience and life-history color a person. The story of how pink traveled from volcanos to wings is the story of life on Earth, the beauty of it and the bewilderment of it, forever defying and dismantling the categories in which we try to contain it.

When Carl Linnaeus laid the foundation of biological nomenclature in 1735, he divided the living world into two categories: Regnum Animale (the “animal kingdom”) and Regnum Vegetabile (the “vegetable kingdom”). Although microscopes had existed for more than a century, he excluded single-celled organisms, unsure where to place them. (It is the nature of the human animal to dismiss and negate what it cannot classify.) More than a century later, the year he coined the word ecology, the German marine biologist Ernst Haeckel proposed a third category for microscopic organisms, which he called Protista — “the kingdom of primitive forms.” (Haeckel was so bewildered by the multifariousness and complexity of fungi, which defy our basic intuitions about life, that he kept moving them between Plantae and Protista, finally settling them in the latter; it would be another century until they were given their very own kingdom or, in the more representative term of mycologist Giuliana Furci, “kindom.”)

Pulsating beneath all these distinctions was the fundamental assumption that all organisms are either eukaryotes, ranging from the unicellular paramecium to the immense blue whale, or prokaryotes — bacteria and all remaining microscopic life-forms.

But then, in 1977, as the Voyager sailed into space carrying the Golden Record meant to represent life on our Pale Blue Dot, the microbiologist and biophysicist Carl Woese made a startling discovery — the tiny organisms found in volcanic hot springs, whose ribosomal DNA sequences he was investigating, turned out to be a wholly different microbial life-form sharing as little with bacteria as it did with eukaryotes. He called it Archaea. Suddenly, the tree of life had a third branch.

Born with grey plumage, flamingos spend the first years of their life feasting almost exclusively on brine shrimp — aquatic crustaceans that in turn feast almost exclusively on organisms containing the same carotenoid pigments that remain in autumn leaves when chlorophyll falls away. Haloarchaea — extremophile Archaea that thrive in hypersaline environments — are a chief source of these carotenoids in shrimp. (They are also why Himalayan salt is pink.) Unperturbed by the unremitting sun exposure of open water, these tiny titans of survival protect their DNA from UV radiation by synthesizing a red carotenoid that makes its way across the metabolic Rube Goldberg machine into the feathers of flamingos.

It is not simply that flamingos metabolize archaea, digesting them to turn their pigments into plumage coloration — modern molecular analysis reveals that archaea still live intact in the feathers of flamingos, perhaps the way our own past moves through us, lives in us, colors our present with the hue of something deeper than memory, something shimmering with the mystery of what makes life alive.