A new study published in the National Academy of Science suggests monogamy may be linked to grandmothers. To be more precise, the study claims that men evolved into monogamous partners thanks to their grandmothers.
The co-author of the study, Prof. Kristen Hawkes, was the one who came up with the “grandmother hypothesis.” He and his colleagues suggested this idea based in 1997, based on a study conducted in the 1980s. Back then, the Hazda hunter-tribe was monitored, rising from Tanzania.
The scientists revealed that older women of the tribe were the ones who collected food for their grandchildren.
Prof. Hawkes, from the Department of Anthropology at the University of Utah, said that when grandmothers fed their grandchildren accordingly, their daughters could conceive more easily at shorter intervals.
The scientific team discovered via computer modelling that daughters being permitted to conceive more, the females, who had a high longevity rate that allowed them to become grandmothers as well, would pass their genes to further generations. Their descendants would also benefit from a longer lifespan. Therefore, grandmothering is believed to be the utterly important factor related to human social systems.
Moreover, computer simulations displayed the fact that 43 percent of women belonging to hunting tribes become grandmothers.
Further on, the computer simulations were also monitored in order to discover a pattern of male to female interaction, according to grandmothering.
For the study, Hawkes’ team made a comparison in between the sex ratio of male and female great apes, and the present populations of hunter-gatherer populations.
Their efforts revealed the fact that the ratio of females being able to bear children doubled, thanks to grandmothering. There would be approximately 111 males for each female.
The computer-generated model would emphasize that monogamous romantic relationships were the result of male forming stable bonds with one female, or just a few women.
Dr. Peter Kim, co-author of the study, from the University of Sydney, reported that older men would be able to reproduce, after women becoming infertile due to the menopause.
Therefore, the menopause would be the main driving factor for the evolution of male-female relationships.
Kim continued by saying that an imbalance was created in time, meaning that men became more competitive regarding females who were still fertile.
But this competition was not successful, as it became more important to find a partner and guard them.
Kim finally pointed out that
“suddenly males’ optimal behavior is to link with one female and to stay and protect them and have all their kids with that female.”
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