Why we don’t see gray birds? They do not live to old age?
Mammals for the color of the wool correspond to the same melanocytes cells that affect the color of the human hair. With age, melanin in hair lows ceases to synthesize, and the animal sad. However, in the wild, do not all wait until old age. But in zoos, where, due to the lack of natural enemies, life expectancy is higher, periodically you can see the gray gorilla or wolverine. It happens, wool becomes asholna in dogs, cats.
The birds are all otherwise. Their color depends not from pigment, but from the structure of keratin – protein, from which feathers consist. In 2015, this found scholars from the University of Sheffield in the UK. On the example of the joke, they proved that each color corresponds to a certain size and structure of a nanopore in the composition of keratin.
If they are round and large, the wide range of light waves is reflected and we see the white bird. (You, by the way, know that the polar bear is actually not white?) Small pores reflect only part of the spectrum waves, and the color of the feathers seems to us blue. Additional colors are formed due to a combination with pigments – yellow and orange carotenoids and dark melanins. Due to ordinary melanin, which absorbs most of the spectrum, black color is ensured.
Albatros’ female named Whisdom is the oldest bird living in the wild. In 2019, at the age of 68, she successfully sadded her egg © John Klavitter / U. S. Fish and Wildlife Service
The study also explained the rarity of green birds in nature. This color is in the spectrum between blue and yellow and is determined by a very narrow wave range. Therefore, recreate it difficult. Usually, green plumage is formed due to a combination of blue with a yellow pigment.
Over time, the diameter of the nanopor is changing, and the color may tackle. However, the gray bird will not still be. Pernata has a different sign, with which you can roughly define age – beak. What he is more, the older its owner.
By the way, the butterflies are not gray for the same reason – their color does not depend on the pigment, but on how light reflects.