The study says that there were food shortages at this time in Northern Europe (10,000-11,000) years ago and the only available food was meat from herds of mammoths, reindeer, bison and horses (for French cave people, presumably). As gathering this involved long, tough hunting trips more men than women died early leaving a surfeit of cavegirls. The girls with lighter hair colour became popular for breeding leading to the sort of increase in numbers that has resulted in fair-haired modern Northern European women.
The lighter hair was a rare mutation initially and would have died out if it hadn’t become so popular with cavemen.
“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 (wouldn’t you know it!) anthropologist.
The theory is that hair and eye colour tend to be uniform in most parts of the world except Europe and those places settled by Europeans. If these hair changes had happened by normal evolutionary methods then it should have taken about 850,000 years to take effect but humans only reached Europe from Africa about 40,000 years ago.
Three Japanese universities (who obviously, also, have nothing better to do) have
isolated the date of the genetic mutation that resulted in blond hair to about 11,000 years ago.
Apparently the reason is that in Africa there was more reliance on fruit gathering, which women could do, but in Europe, where there was amore of a meat diet, gathering food was the preserve of male hunters whilst women stayed at home making fur bikinis. The men got trampled by mammoths, tossed by deer antlers, kicked by horses and gored by bison. So any remaining men were in short supply and were fought over by the women. Blonde hair, apparently, is an indicator of higher oestrogen levels so blondes became selected as better breeders.
Now this is all very well, but it assumes that cavegirls didn’t go hunting but, as this obviously historically accurate painting shows, they may well have done. It also assumes that cavemen only had one mate at a time.
"He's mine, cave-bitch!"
A big assumption, although this may be true. After all, you might think that it is a great idea to have four or five cavegirls in fur bikinis wrestling over who’s going to share your cave bear fur-lined sleeping area but after a short while they would start nagging you and ganging up on you and generally acting like groups of young women do to men. You would quickly evolve into a situation where one cavegirl was quite enough (well, and maybe another one on the side in a cave the other side of the hills).
One thing you can be sure of, though, is that as soon as a dark haired girl saw that her blonde sisters were getting all the attention she would have been straight off to the tribal witch to get her to create a concoction that would dye her hair blonde.