Japanese scientists have found that the viability of a species depends on how many color options its representatives have. The greater the variety of colors, the better. This applies not only to insects and birds, but also mammals - including humans.
Survival secret
In 2016, an international team of scientists, analyzing information on more than ten thousand species of birds, established a link between the diversity of their color and the likelihood of extinction of the species. Individuals of different colors - and this determines the strategy of hunting, protection from predators and relationships with the opposite sex - as a rule, they choose different ecological niches. And the wider these possibilities, the lower the risk of extinction.
According to the authors of the work, the color of the plumage serves as a kind of protection against abrupt and unpredictable changes in habitat conditions. True, why this is possible within one species, scientists then did not figure it out.
Three years later, Japanese biologists, based on a huge body of data on insects and vertebrates, suggested that this principle applies to most animals living on the planet. In total, scientists analyzed information on 93 species of dragonflies, 83 species of butterflies, 71 species of fish, 73 - amphibians, 156 - reptiles, 145 - birds and 155 species of mammals. In addition to the variety of colors, experts paid attention to the range of climatic conditions in which animals live, and their number.
According to the work of an international group of researchers, bird species within which there are a large number of color options are less likely to be endangered.
It turned out that the more options for the color of wool, scales or plumage within one species, the wider it is represented on the planet and the lower the risk of its extinction. Differing colors allow more full use of available resources and better withstand adverse factors, the authors of the study say.
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Aggressiveness in color
According to an international team of scientists, the appearance and consolidation of different colors within the same species is sometimes possible due to the protection that individuals of the more common color provide them. At least, this explanation seems quite plausible for the dart frogs of the species Dendrobates tinctorius, living in the jungles of South America.
These amphibians are very venomous, with bright yellow or blue spots on their backs, warning birds not to eat them. But there are individuals, rather few in number, with quieter white markings that do not resemble warning coloration. In theory, they are less protected and should be discarded by natural selection. However, this does not happen.
Biologists, who conducted a series of experiments, came to the conclusion that yellow frogs with their toxic color protect not only themselves, but also less common white individuals. Birds are afraid of them along with the yellow ones. That is why animals of such an unusual color have taken root in the population.
Often the color of skin, coat or feathers is determined by many genes, each of which can control other unrelated processes in the body, such as character, health. Thus, it is known that the aggressiveness of small poison dart frogs of the species Oophaga pumilio depends on the color.
Experiments show that red little poison dart frogs are much more aggressive than green representatives of this species.
These are territorial amphibians, they know how to defend their piece of land. When scientists planted frogs of other species in the enclosures, the red-skinned individuals shook their paws more, pushed and shoved their opponents. They more often than their green relatives won single combat and drove away uninvited guests.
Previously, researchers showed that the coat color of domestic cats can also indicate their level of aggression towards humans. So, the tricolor, black-and-white and gray-white females turned out to be the most evil. But cats of this color were much kinder to their owners.
Who lives longer
Australian researchers have identified the relationship between health and life expectancy with coat color in Labradors, analyzing data on 30 thousand individuals. Those with a chocolate color are more likely to suffer from otitis media and dermatitis. They live on average 1.4 years less than their golden and black congeners.
It turned out that this tendency is also observed in humans. In one of the works, specialists surveyed over two hundred thousand people and analyzed their genomes. The analysis showed that the lighter a person's hair is, the later they reach puberty and the more likely they are to reach old age. In addition, blondes and fair-haired people are less likely to develop heart attacks, strokes and type 2 diabetes.
This is because gene variants that correlate with puberty are located next to genes that affect skin and hair color. Both of these processes can be connected through the pituitary gland, a gland on the lower surface of the brain. It simultaneously produces hormones that regulate the development of the gonads, and those that affect pigmentation.
Author: Alfiya Enikeeva