 We explain the science of skin color What causes human skin tones to vary among different populations of people well a chemical called melanin That's produced in our bodies gives the skin a darker color the more people produce the darker their skin will be melanin's purpose is to work as a natural sunscreen to absorb the Sun's UV rays With that in mind regional skin colors developed naturally as a response to different climates when our ancestors migrated across the globe Tropical climates provided more UV exposure than other regions. However, too much exposure is damaging This means natives from regions like the equator had darker skin since their bodies produced more melanin to protect against these harmful rays On the other hand too little UV light is also damaging because UV light provides vitamin D Which is essential to build our bones Therefore natives from cooler regions north and south of the equator often had lighter skin as a result of less UV exposure Since they produced less melanin to block UV rays. This ensured they received the vitamin D. They needed It's important to note that diet also plays a role in the development of skin tones For example a high seafood diet provides an alternate source of vitamin D That's why native people from Alaska and Canada remained dark-skinned in low UV areas All in all the variation in our skin tones is only due to a little natural sunscreen Though we may not look alike we are all human and together we share our world