Inuits live in very cold climates, why do they have dark skin?

- asks Anonymous

An Alaskan Inuk. [CREDIT: CULTUREBY.COM]
By | Posted June 18, 2007
Posted in: Ever Wondered?, Life Science
Tags: , , ,

Despite the frigid, ice covered landscape of Northern Canada and Alaska, the Inuits remain warm beneath parkas of animal hide. Warm and…tan. Despite barely seeing the light of day, the native people’s skin retains a bronze glow.

Even in the early 20th century, scientists were trying to understand and map skin color. Felix Von Luschan, a doctor and anthropologist, created a Human Skin Colour Distribution containing 36 different color tiles to characterize skin tones. The further a person’s ancestors are from the equator, the fairer the person’s skin should be, according to his scale.

More recently, Penn State anthropologists Nina Jablonski and George Chaplin wrote in a 2000 edition of Science that there is a correlation between the skin color in people residing in an area for more than 500 years and their exposure to ultraviolet light. They even came up with an equation that determined the pigments of a population based on sun exposure and length of time spent living in an area. But neither their nor Von Luschan’s research answered the question of an Inuk’s bronze complexion without exposure to a great deal of sun.

Jablonski and Chaplin were onto something though, when they realized that the body’s interaction with UV rays from the sun, was tied together with skin tone. Skin color is determined genetically. Genes tell the body how much of the two types of melanin, the pigment that helps to determine the skin color, to produce. Pheomelanin causes reddish yellow pigments, and eumelanin gives deep brown coloring. But skin tone is not all genetic: more melanin is produced when you are out in the sun. Sunlight exposure causes the optic nerve to signal the pituitary glad to release more melanin. Thus, you tan.

Ultraviolet, or UV rays, from the sun are responsible for activating the melanin. As melanin levels rise and our body’s natural pigment darkens, protection against the sun’s rays increases. Too much UV exposure can deplete vitamin B folate –used by the cells to create DNA. On a smaller scale, the rays can also cause painful sunburns, with too much exposure leading to cancer.

However, UV rays aren’t all bad for us: they naturally convert cholesterol into Vitamin D, which is crucial in protecting the body against certain cancers, heart disease, diabetes, and mental illnesses.

When the ancestors of modern man separated from apes, they were covered in hair. Little UV light reached their skin and as a result, anthropologists believe they were fair skinned. As modern humans evolved however, their body hair became finer and thinner, leaving their skin more exposed to the equatorial sun. To adapt, thier bodies produced more melanin to protect them from damaging UV rays. Increased melanin made their skin become darker.

As early humans started migrating north into Europe and east into Asia, they were exposed to different amounts of sun. Those who went north found their dark skin worked against them–preventing them from absorbing enough sunlight to create vitamin D. To adapt, these humans started producing less melanin.

But Inuits vitamin D intake wasn’t dependent upon the sun. They get all that they need from their diet, heavy on types of fatty fish that are naturally rich in vitamin D. The plentiful amounts of the vitamin kept them from developing less melanin. In fact, before milk was fortified with D, people living outside of Northern Canada and Alaska loaded their diets with fishy products, such as cod liver oil, to get their daily supplement. So despite their chilly climate and lack of sun exposure, it’s the Inuit diet that has kept them in their natural glow.

Editor’s note: The content of this story has been changed based on a readers comment about the plural and singular usage of the word Inuit. Where ‘Inuit’ was originally referencing a single person, the world has been changed to Inuk.

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  1. This is absolutely absurd. Vitamin D cannot and will not change genetic coding. It does not explain the Russian pigment or European pigment predominantly white colored. Furthermore, it does not explain why thousands of years have passed and yet these Eskimos who supposedly migrated to a cooler climate to get away from the sun are still dark skinned. If this were true and the exposure to the sun and vitamin D changed our genetic coding then these cultures today would be the palest humans alive due to their lack of sun exposure. Yes they eat fish and get vitamin D that way but not near enough what the sun provides. This is so dumb its laughable.

    Tyler, July 20, 2017 at 10:23 am
  2. I wouldn’t exactly call Eskimo skin ‘dark’ y’know. Colored sure, but not heavy in melanin.

    Fingal, August 9, 2017 at 3:10 pm
  3. Tyler you didn’t read the whole thing, it doesn’t say anything like that

    trsystr, September 5, 2017 at 12:06 pm
  4. Forgive the typos, I was tying with my tablet. Here’s a rewrite:

    Sometimes we should just learn to admit we are wrong or lack understanding. It seems like we want to have answers so bad that we create explanations that makes no sense but call it fact because “science” . It’s okay to admit that we don’t truly understand why some people are darker than others because let’s be honest, the Inuits shouldn’t be so melanin rich in that climate. They should have been just like the Europeans.

    Von Dif, November 16, 2017 at 10:13 am
  5. This article seems to conflates cold temperature of the Arctic climate with sun exposure. Are there significantly fewer sunny days a year in the Arctic, bearing in mind the light months? Inuits are prodigious hunters, wouldn’t tan skin be a massive advantage when spending consecutive hours outside hunting? If it’s easy to get sunburn in from an afternoon of skiing, just imagine spending all day out in the bright tundra with no chance of shade or apres-ski refreshments other than seal blubber. No thanks.

    Dale, December 23, 2017 at 11:13 am
  6. Theory 1:
    Europeans became lighter skinned to absorb more sunlight for Vitamin D synthesis.

    Fact:
    The Inuit live in the same environment as Northern Europeans.

    Expectation:
    The Inuit should have the same color has Northern Europeans.

    Fact:
    The Inuit are darker than Northern Europeans.

    ————–

    Yes, there is a discrepancy between our expectations and the actual fact. However, the actual theory proposed (that Inuit get Vitamin D from diet, and therefore did not become lighter) seems rather ridiculous. Norwegians have always eaten fatty fish (full of Vitamin D), yet they are still very pale. Perhaps the initial theory of whiteness as a Vitamin D adaptation needs to be revisited. There may be additional variables influencing the evolution of lighter skin.

    Sidra Ahmed, January 16, 2018 at 8:01 am
  7. This is a great example of selection and evolution. If a dark skinned population moved to the frigid north, we would expect evolution to favor the selection of lighter skin over time. Such that, given 500-1000 years, the population should be lighter on average. The selection may be on synthesis of vitamin D, as we know dark skinned populations become Rickets-prone without UV light to synthesize Vitamin D and calcium. Now if one population already has a source of vitamin D, through their diet, then there is no need for evolution to favor lighter skin. It will not be a selective pressure, so they maintain their original pigmentation levels despite hundreds of years in UV-limited region.

    James, January 22, 2018 at 2:08 pm
  8. First off, I am Inuit but that does not make me en expert. Here are some things I know though:
    Most ‘modern’ Inuit people have only been in the region for a thousand years or less, descendants of the Thule from Alaska. Yes, the traditional diet does include vitamin D from animal sources. There is lots of sunlight in the summer, but there are so many bugs that skin has to be pretty covered up anyway. However, in winter although the daylight hours are short the sun gets reflected up again by the snow, leading to increased exposure on that small portion of skin that is not covered. More melanin could help to have less skin damage.
    Also something that hasn’t been stated in this article or the comments is that pretty much all North American indigenous people have dark skin when compared to Europeans. The ancestors of the Inuit people did come from inland and further south originally. My guess is that we have darker skin simply because it’s a passed down trait with no evolutionary reason to have lighter skin.

    Gina Chicksi, February 24, 2018 at 3:28 am
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