Grandmothers: Our Evolutionary Heroes

Unlike many other species, humans have the unique ability to live well past their child-bearing years. Biologically, these women can no longer reproduce yet their roles have become embedded into our species. What is the role of a grandmother? How exactly did she benefit our evolution?

Thanks to a team of researchers and a computer simulator, the “grandmother hypothesis” offers an exciting perspective on the unique role of grandmothers in our evolutionary history. According to the study, grandmothers held more than an instrumental role in caring for their communities. Their presence may have helped our species develop better social skills, larger brains, and increased our lifespan.

“Grandmothering was the initial step toward making us who we are,” says researcher Kristen Hawkes in a recent article published by the Smithsonian. Kristen and her team provide mathematical evidence for their hypothesis by simulating what would happen if menopause was introduced to 1% of the females in a primate species. While this may seem like a small sample, the introduction of a human life-span to the group led to amazing discoveries. Over the course of 60,000 simulated years and thousands of generations, these females, gifted with the unique ability to live past child-rearing years, were able to lengthen the life spans of their own families.

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In short, creating the role of a grandmother to the group, increased the lifespan from an average of 40 years to 60.
Why does this happen? To start, from an evolutionary standpoint, the grandmother is an instrumental member of the family unit. The grandmother acts as primary care provider, helping her daughter look after and feed the children in the family. While it may be easy caring for one baby, a mother faces serious time constraints as soon as she bears a second or third child. Her focus revolves around the new baby; providing more care to the infant and less care to the older children.

But what would happen to these older children if a grandmother was not present? They are not capable of finding food. They’d receive far less attention. Their odds of surviving childhood would decrease dramatically.

And when it comes to social interactions, the grandmother mandated that humans rely on each other and engage each other more frequently. While you may not associate engagement with the ability to increase brain size, these types of social interactions are what separates humans from other species. It’s the constant adopting of new skills that led to our larger and more flexible brains.

The role of a grandmother is unique. It’s powerful, selfless, and continues to help our species develop. While we may not face the same harsh living conditions as our ancestors, I’d like to think our need for their role is still as pressing as it was thousands of years ago.

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