Scientists have discovered that bird of paradise feathers are physically structured in such a way as to absorb nearly all light that reaches them, much like a black hole. Viewers of the acclaimed nature documentary series Planet Earth may recall the bird of paradise from its featured segment, in which male members of the species display their pitch-black feathers, punctuated with spots of vibrant color, while they dance in hopes of attracting a mate. These feathers are not simply a darker shade of black. In fact, their physical structure enables a level of near-total light absorption that is rare in the animal kingdom.
Optical measurements of the bird of paradise feathers indicate that they are capable of absorbing 99.95% of light that reaches it, a similar level of light absorption to man-made ultra-black materials such as the lining of telescopes. “Evolution sometimes ends up with the same solutions as humans,” said senior author and Yale professor Rick Prum, according to Phys.org. The super-black feathers, coupled with patches of bright color, function as an evolved optical illusion. “An apple looks red to us whether it is sitting in the bright sunlight or in the shade because all vertebrate eyes and brains have special wiring to adjust their perception of the world according to ambient light,” said co-lead author Dakota “Cody” McCoy. “Birds of paradise, with their super-black plumage, increase the brilliance of adjacent colors to our eyes, just as we perceive the red even though the apple is in the shade.”
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The difference between regular feathers and super-black feathers is found in the structure of the main stem and barbs in the feather. Where regular feather has single barbs attached to the main stem, super-black feathers have many spines that serve to create a dense thicket of feathers. “When you have no flat surfaces, the light gets completely absorbed by the feather,” said McCoy, according to Gizmodo. While these feathers are unusually effective at absorbing light, the light-absorption effect is most strong when seen from directly ahead. Still, the biologically developed super-blackness may offer lessons to engineering humans. “Sexual selection has produced some of the most remarkable traits in nature,” Prum said, according to Phys.org. “Hopefully, engineers can use what the bird of paradise teaches us to improve our own human technologies as well.”
Images via Ed Shoales/Birds-of-Paradise Project and Yale University
