Peacock feathers: why are they so beautiful?


A livestock and companion animal, this bird belonging to the Phasianidae family is native to India. Although the female may appear dull, at the time of reproduction she benefits from the male’s courtship adorned with a thousand iridescent shimmers. Where do the magnificent colors of the peacock’s livery come from? What processes allow the animal to present such beautiful feathers?

A colorless feather that plays with Bragg diffraction

During the courtship display, the peacock shakes its beautiful tail feathers in a myriad of metallic blue and green reflections. He does cartwheels to seduce his girlfriend. While many species get the beautiful colors of their ramblings from a pigment, the same is not true for this bird. The beautiful peacock feather, made up of a multitude of layers of scales, ends with a black layer, the natural color of its feather. A complex phenomenon, Bragg diffraction, is in fact at the origin of the particular tones of the bird’s plumage.

In nature, depending on whether the surface is white, black or red, the wavelengths are not reflected in the same way. The black object absorbs all the colors, while the white surface reflects them all. The particularity of the peacock feather lies in its crystalline structure which will disrupt the way in which light is reflected or absorbed. Made up of all the wavelengths of the rainbow and coming from all directions, the light thus activates different areas of the feather according to the crystals which constitute it and reveals the dominant color.

The special phenomenon of iridescence adds this characteristic shimmer to the beauty of peacock feathers

While certain colors are amplified and others diminished by Bragg diffraction, the peacock benefits from another asset to adorn its livery with unparalleled beauty in your garden: iridescence. Depending on the direction of the light, the peacock’s beautiful feathers display tones of blue to turquoise, while the yellow will transform from orange to yellow-green. The tilt of the feather causes a variation between two waves of light and causes this characteristic iridescent shimmer. The diffraction of light caused by the lamellar structure of its feathers adds the apparent metallic reflection to its livery.

The peacock, an artist who also plays with the geometry of his eyespots to seduce his girlfriend and impress predators

A true artist of physics, the peacock displays a particular geometric pattern on its beautiful feathers. Each feather end is enhanced with a design similar to an eye. These eyespots are not intended to simply seduce females, they are also supposed to deter predators from rubbing against the peacock during courtship.

The length of the feather and the size of the fan count less in the art of seduction in the Phasianid than its ability to resonate with their magnificent color. The bird that will delight the peahen’s heart must make the hundred feathers that adorn its wheel vibrate so that the eyespots appear motionless against a moving background.

Interference, Bragg refraction and iridescence carry all the beauty of the peacock’s feathers. But these are not the only animals that rely on physics and light to display shimmering colorful adornments:

Scutelleridae or shield bugs; Hummingbirds; Gooty’s ornamental tarantula.

Butterflies, fish, birds and minerals can also be adorned with shimmering and metallic colors thanks to the phenomena of Bragg diffraction and iridescence.

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