A new anthropological study argues that blondes developed in Northern Europe when the competition for males was particularly intense:
According to the study, north European women evolved blonde hair and blue eyes at the end of the Ice Age to make them stand out from their rivals at a time of fierce competition for scarce males. The study argues that blond hair originated in the region because of food shortages 10,000-11,000 years ago. Until then, humans had the dark brown hair and dark eyes that still dominate in the rest of the world. Almost the only sustenance in northern Europe came from roaming herds of mammoths, reindeer, bison and horses. Finding them required long, arduous hunting trips in which numerous males died, leading to a high ratio of surviving women to men.
Lighter hair colours, which started as rare mutations, became popular for breeding and numbers increased dramatically, according to the research, published under the aegis of the University of St Andrews.
“Human hair and eye colour are unusually diverse in northern and eastern Europe (and their) origin over a short span of evolutionary time indicates some kind of selection,” says the study by Peter Frost, a Canadian anthropologist. Frost adds that the high death rate among male hunters “increased the pressures of sexual selection on early European women, one possible outcome being an unusual complex of colour traits.” [...]
Just how such variety emerged over such a short period of time in one part of the world has long been a mystery. According to the new research, if the changes had occurred by the usual processes of evolution, they would have taken about 850,000 years. But modern humans, emigrating from Africa, reached Europe only 35,000-40,000 years ago.
Instead, Frost attributes the rapid evolution to how they gathered food. In Africa there was less dependence on animals and women were able to collect fruit for themselves. In Europe, by contrast, food gathering was almost exclusively a male hunter’s preserve. The retreating ice sheets left behind a landscape of fertile soil with plenty of grass and moss for herbivorous animals to eat, but few plants edible for humans. Women therefore took on jobs such as building shelters and making clothes while the men went on hunting trips, where the death rate was high.
The increase in competition for males led to rapid change as women struggled to evolve the most alluring qualities. Frost believes his theory is supported by studies which show blonde hair is an indicator for high oestrogen levels in women.