Did you know that women are among the few living beings (along with killer whales) that we live beyond reproductive age?
Since the purposes of evolutionary play are survival and reproduction, scientists considered studying the reason for our long existence and whether grandmothers can hold the key to human evolution.
So in the sixties, they created the 'grandmother's hypothesis' that is based on the idea that grandmothers' help allows mothers to have more children. Now, a new study, conducted by the University of Turku, Finland, shows that the grandmother's relationship with her grandchildren improves children's health.
From the 'grandmother's hypothesis'
Menopause and prolonged post-productive life separate humans from other primates, but why this evolution remains a puzzle for scientists.
The study 'Limits of the benefits for the physical conditioning of prolonged post-productive life in women', published only a few days ago in the journal Current Biology, analyzed the historical records of the Finnish churches to understand the role of the 'mature' woman .
In Babies and more Five good reasons, according to science, why it is positive that grandparents take care of their grandchildren Researchers at Human Life History Science at the University of Turku explain that:
"From these records, we investigate the" grandmother's hypothesis "that proposes that the long post-productive life of human women has evolved because grandmothers can help their grandchildren. A key question to understand why we live so long. it had never been studied before until what age the presence of the grandmother brings benefits to their families. "
Therefore, the team investigated how the presence of grandmothers of different ages and in different health conditions affected the survival of grandchildren born between 1731 and 1890, when living conditions were still hard and infant mortality was high.
It was shown that the presence of maternal grandmothers increased the survival of children from 2 to 5 years of age by almost 30%, which confirms that the prolonged longevity of women may be favored by natural selection.
Paternal grandmothers, better young
But research has also revealed that grandchildren who lived with a paternal grandmother over 75 were 37% less likely to survive beyond their second birthday.
Also the probability of survival was lower when the paternal grandmother was less than a year after his death, which is translated by fragility and poor health. In this sense, the director of the study, Simon Chapman explains that:
"We were a little surprised to discover that the old and / or weak paternal grandmothers were really detrimental to the survival of the grandchildren. Although we cannot assure why, we suspect that it is the result of some kind of competition for living under the same roof, since parents may have needed to divide their limited resources between their dependent children and the dependent grandmother. "
The finding, says the researcher, "It's really important, because it underlines the importance of staying healthier for a longer period."
In Babies and more, do grandchildren want maternal grandmothers more?According to the study, post-productive life could have evolved, at least in part, due to the beneficial effects of grandmothers, but such benefits decrease with age as opportunities and the ability to provide help diminish, which limits the evolution of an even longer life.
Life today in most countries is much longer than in the past, perhaps because medicine has allowed us to exceed the limit considered 'natural' of longevity.
The scientists conclude that:
"Our finding that grandmothers with poor health are associated with higher infant mortality in the same home underlines the importance of healthy aging and discovering ways to prolong healthy life and increase life expectancy. "
Grandmothers are important for the success of their families, and they have always been throughout our evolutionary history.
Now this study has shown that the fragility and health of grandmothers are vitally important for them and for subsequent generations. Therefore:
"Improving old-age health and the opportunities of older people to remain involved with their families could benefit both grandmothers and their families in multiple ways."Photos | iStock
