Few animals are as classy as the penguin, sporting a fashionable and classy tuxedo-like attire, elegantly designed for a flightless life in the waters of the Southern Hemisphere. Whether waddling amongst its young in snowy Antarctica or swimming in the northern shores of the Galápagos Islands, the familiar image of this black and white animal is truly iconic. The Little Blue Penguin, however, reminds evolutionary biologists and wildlife enthusiasts that the world is rarely black and white.
Adding a splash of color to its morphology, this species of penguin found along the coastline of Australia and New Zealand, has a striking blue tint on its head, upperparts, and flippers that contrasts the usual white belly. Seeking to understand this peculiar distribution of color, scientists used sophisticated equipment of microscopy and spectroscopy to develop a structural and optical analysis of the penguin barb structures. Outlined in a paper entitled, “Colour-producing β-keratin nanofibres in blue penguin (Eudyptula minor) feathers,” published recently in Biology Letters, the researchers concluded that the blue coloring is derived from the unique packaging of the keratin nanofibers. When light strikes the fibers, all wavelengths of light, expect blue, pass through the feathers, and produce the observable bluish color. Though the authors report that similar nanofibers are found in the feathers and skin of other birds and mammals through convergent evolution, they also note the feathers of the blue penguin “represent the first reported case of a non-iridescent structural colour based on two-dimensional quasi-ordered arrays of parallel β-keratin nanofibres.”
The study adds considerable knowledge to known mechanisms of color production in birds and biophotonics by paying homage to a species of penguin that dared to be different from its relatives, adding a splash of color to the biological world.