Scientists in California were amazed to find that Stone Age women evolved denser breasts to deal with harsh winters.
Stone Age humans who lived near the Arctic Circle some 25,000 years ago developed denser breasts in order to survive the austere conditions in which they lived, a remarkable new study claims. Because of this adaptation, this group of humans that lived near what is now the Bering Strait was able to provide their children enough vitamin D through breast milk despite the difficult climate.
Researchers stumbled upon this revelation as they were studying a genetic mutation that was common to both East Asians and Native Americans in an attempt to better understand early humans. This discovery would be an extremely rare case where scientists could prove that humanity evolved to adapt to a difficult environment.
Specifically, researchers believe the mothers who survived the harsh winters had a mutation in the EDAR gene that enabled them to develop more milk duct branches, resulting in denser breasts. It shows just how important the mother-infant relationship is and how much it is rooted in early human survival.
“The critical role that breast feeding plays in infant survival may have led, during the last ice age, to a common genetic mutation in East Asians and Native Americans that also, surprisingly, affects the shape of their teeth,” reads a statement from the University of California at Berkeley. “The genetic mutation, which probably arose 20,000 years ago, increases the branching density of mammary ducts in the breasts, potentially providing more fat and vitamin D to infants living in the far north where the scarcity of ultraviolet radiation makes it difficult to produce vitamin D in the skin.”