Why do Europeans have colored eyes and hair but Siberians, Inuits, Mongolians don't they live in much colder extreme places?
- 7 months ago
Eye color and hair color are not determined by environment. They are genetic. At some point there was a genetic mutation in ancestral european populations whereby eye color was different than the norm (brown). Same goes for hair. I think one theory is that these traits were favored in the population and encouraged.
By the way. Some Melanesian populations (or all.I can't remember) also have blonde hair, with no connection to europeans. Just an independent mutation.
- JimZLv 78 months ago
What you are calling "colored" eyes is actually from a lack of pigment, melanin. The "colored" eyes are brown eyes. A lack of melanin led to the blue eyes. The same is pretty much true of hair too.
- Big MamaLv 68 months ago
I've read that domesticated animals are more diverse when it comes to hair and eye color.
We can see this in wolves vs. dogs, wild vs. domestic cats and boars vs. domestic pigs. I don't know if that also works for present-day Euros, but it's clear certain variants associated to light eyes, hair and skin have been selected for within the past 10,000 years in Europe.
In the case of Inuits/Siberians/Mongolians it's possible not enough generations have passed since they colonized those lands (at least 5,000 years are necessary to develop the mutations associated to light skin) and/or their lifestyle is/was closer to that of hunter-gatherers (Inuit).
- ZirpLv 78 months ago
eyecolour and haircolour are determined by genetics, not by temperature
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- Anonymous8 months ago
Only some Europeans have green, blue or hazel colored eyes. Many of them still have brown eyes. Some Africans also have blue eyes, and some Pacific Islanders have blond hair. These facts suggest that blue and green eyes and blond and red hair were not adaptations to the cold climate. Light skin tones, OTOH, are adaptations to the cold. That is because when people live in cold climates, they need some way to stay warm, and that way is to wear animal skins or clothes made from plant material. When clothes are worn, they block out the sun and that can cause vitamin D shortage because vitamin D is made by skin cells but the process needs to be helped by UV light. Vitamin D helps us absorb calcium from our food, and its shortage can lead to rickets, which in turn can lead to broken bones, deformed bones and even death.
Light skin allow more UV light to reach the skin that is exposed, and therefore it can help prevent rickets, a disease that can cripple a person so that he can no longer hunt or provide enough calcium to a developing fetus and baby. Other cold adaptations include shorter arms and legs, taller and narrower nose bridge , shorter stature, more facial and body hair, a rounded torso, and thin lips because these features reduce the amount of skin surface exposed to the cold climate and therefore reduces heat loss to the environment. Some of these features are in fact found in other cold adapted people, such as the Siberians, Mongolians, northern Chinese, Koreans and Japanese. They are also found in some SE Asians but that is the result of northern Chinese migrating south and admixing with SE Asians, not because SE Asians adapted to the cold climate.
Green and blue eye colors are the result of a lack of eumelanin, a dark brown or black pigment that also makes the skin and hair dark. The lack of pigments inside the eye does increase vitamin D production, but since people already have light skin the additional vitamin D would not help much. In fact, people with green and blue eyes have a higher incidence of eye cancer. Therefore blue and green eyes are at best selectively neutral, meaning they neither benefit or are they hurt by their eye color. If that is the case, then it would be difficult for such a trait to spread rapidly. Scientists estimate that the mutation for blue eyes happened about 10,000 years ago, and by that time the ice age had already ended. That is additional evidence that these eye colors did not evolve as an adaption to the cold. It is little wonder than most people around the world do not have blue or green eyes. It provides little benefit and in fact it may shorten their lives if they contract eye cancer as a result.
- Gray BoldLv 78 months ago
Europeans have been at those latitudes for tens of thousands of years. They are partially descended from the Cro-Magnon (European cavemen). Changing skin color is a long process. Other people living at those latitudes now, such as Eskimos and the Inuit, have only been there for a few thousand years. A another reason is lifestyle. Europeans rely on agriculture for their primary food source. During winter, they really don't go outside. Eskimos and the Inuit live a totally different lifestyle.
They spend a lot of time on the ice and snow, hunting and fishing. Exposure to reflected sunlight can be quite damaging,
due to the ultraviolet rays. Therefore maintaining dark skin and brown eyes is important, since melanin offers better protection against sunlight.
- Anonymous8 months ago
Inbreeding. Aka the Founder effect. Doesn't have anything to do with cold temps. There's another blue eyed mutation on a South Asian island.
- yLv 78 months ago
Used to be the sunlight exposure, then UV was added to to it. Many still cling to it. Some thought it may have been Neanderthal, but that doesn't quite work either. Many are also leaning towards selection, blue and blond were preferred for whatever reason in Europe.
Basically, it could be none of the above or any combination of factors. The more we look at that question with today's knowledge, the more elusive the answer has actually become.