Thank Grandma for longevity

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Grandmothers have driven the evolution of longer lifespans, extending them by around 25 years in a theoretical population of apes, according to a mathematical model that tests the 'grandmother hypothesis'.

According to this theory, women evolved lifespans that extend well past the menopause because older women can boost their daughters' fertility — by taking care of grandchildren. Kristen Hawkes at the University of Utah in Salt Lake City and her colleagues modelled a population of apes, and found that their lifespans evolved from an ape-like range of around 35 years to a human one of roughly 60 years when older females contributed to infant care. Grandmothers enabled mothers to have their next baby sooner without reducing their previous offspring's chances of survival.

Proc. R. Soc. B http://dx.doi.org/10.1098/rspb.2012.1751 (2012)


  1. Report this comment #52098

    Peter Gibson said:

    The granny theory, although thread worn, has a point. It must be supported by the sociobiological belief that grannies are concerned with the success of their germ line. They will favour their offspring over that of other grannies. Lionesses care for their sisters? cubs for selfish reasons. However, they are a family whereas grannies belong to society. The chimp grannies tied to their grandchildren would work if offspring learnt a lot from them and them alone. I suspect any self-respecting chimp can learn all they need from other unrelated chimps. This same goes same for humans who as soon as possible relinquish the rearing of their offspring to others. There is a lot of guff talked about mothers teaching their children to read. The only reason that the community takes responsibility is that it boosts the groups, society, which is in completion with other groups. This switches the argument from to kin to group selection. However group selection, except amongst sociologists, is non-pc nowadays. So we are back to self-interested grannies. But perhaps the grannies are working unpaid for the group and not their grandchildren. Grannies become child minders. Actually the state supports most grannies and therefore their children. Children learn little from their grannies except perhaps not to step in front of seeding cars. If all that can be proved by maths I have the greatest admiration for mathematicians.

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