The reason why humans live longer than other mammals is because of our great-great-great... grandmas, a new study informs. Scientists believe that a deciding factor for the longevity of the human species was not the fact that hunters found food, allowing the women to give birth to children in a safe home but that the grandmothers cared for the next generation, while the parents took care of the daily activities needed for life.
Grandma's care allowed for the women to have more babies at a younger age, which in turn led to the long-lived genes of the grandparents to be passed on to the next generation. This ultimately led to people living longer.
"It looks like our grandmothers were of decisive significance for the development of the modern family, as we know it today, " comments author of the study prof. John Kristen.
The study, published in the Proceedings journal of the National Academy of Sciences of England, stands at odds with the traditional view that the family was the result of the male hunters feeding the females and their offspring, in exchange for the recognition of being the fathers of those children, so that the males would have a progeny and pass on their genes.
Prof. Kristen postulates that the help they received in rearing the adolescent children and the mothers' freedom from this responsibility was the key to human evolution. This allowed the number of people to grow to such a degree that they would rule the Earth. For their study the researchers conducted 60 computer simulations of human evolution - 30 simulations with humans developing with help from grandma and 30 without them.
The simulations showed how the male-female sex ratios changed over time. As time passed, the men grew to outnumber the females significantly, in contrast to monkey populations, where there are several females for each male. Prof. Kristen explains that this led to greater numbers of male representatives of the group wanting to become fathers. The only way this could happen was for them to set their eyes on the more fertile and therefore younger women.
"The older women, who were no longer of childbearing age, began to care for the children so they wouldn't be thrown out of the group and this gave the younger women more time to have more babies. And this was ultimately how human genes became more long-lived and were passed down to the next generations, " states Kristen. According to him, this process in evolution began long ago in prehistoric times with the very dawn of mankind.