We humans, along with several other higher species, need elders and elders need us. From our early ancestors to today, this need is coded into our biology and shapes how we survive.

Take elephants as an example. They live in family groups led by the oldest females and walk long distances as they search for food. When the group encounters potential danger such as possible predators or unfamiliar elephants, the matriarch signals if they should continue grazing or gather into a defensive huddle. Researchers say families with the oldest matriarchs are best able to determine genuine threat.  The older the matriarch, the less energy wasted on false threats and the more calves  survive, a clear connection between wisdom of elders and success of the community.

Or take orcas. Female orcas stop reproducing around the ago of 50 and can live another 40 years. (Male orcas tend to die much sooner.)  Older females take on a leadership role. When hunting, the matriarch generally swims at the head of the pod and directs its movements, using decades of hunting experience to find elusive prey. Researcher Lauren Brent is quoted in a Smithsonian article saying,  “One way post-reproductive females may boost the survival of their kin is through the transfer of ecological knowledge. The value gained from the wisdom of elders can help explain why female killer whales and humans continue to live long after they have stopped reproducing.”

(I wonder if one of the many reasons elephants and orcas die many decades younger in captivity than they do in the wild has to do with being robbed of their essential roles as providers and wisdom-bearers.)

Which leads us to the evolutionary benefit of human grandmothers. Decades ago, anthropologist Kristen Hawkes developed what she called the “Grandmother Hypothesis.” Dr, Hawkes demonstrated (now with an updated mathematical model) that women historically live so far into their elder years because  there’s a significant survival advantage to the family when grandmothers pitch in. From the earliest roots of humanity, grandmothers gathered food, helped raise the young, and reinforced social cohesion. (In fact, field studies indicated men successfully brought meat home from the hunt less than four percent of the time while gathering by mothers and grandmothers provided the rest of the diet.)

Children whose grandmothers helped nurture them were more likely to survive, thereby  perpetuating genes that selected for women who experience mid-life menopause and vigorous old age.  Dr. Hawkes argues that grandmothers, in our evolutionary past, helped bring about bigger brains, pair bonding, even a doubling of the human lifespan. Grandmothers, she contends, make us human.

But what about grandfathers, aunts, uncles, other elders who live nearby? It seems the Grandmother Hypothesis doesn’t go far enough.  Evolutionary anthropologist Michael Gurven says increased survival and group cohesion has to do with “embodied capital” — the kind of knowledge that is acquired by experience and transmitted to others.  More effective hunting strategies and more skilled foraging is passed on by example, helping one’s people thrive.

Our very biology is rooted in and stirred by the need to protect our community. Even the sleep patterns of elders may stem from what benefits our tribe.  The dark hours have, throughout time, been the most dangerous for humans. But if we look at variations in sleep patterns across a spectrum of ages, we see why it wasn’t necessary to post sentinels at the campfire or at the doorway of the hut. Healthy old people tend to go to sleep earlier, don’t sleep as deeply, wake more easily, get up earlier, and may need less overall sleep.  Teens and young adults stay up later, sleep more deeply, and wake later.

As evidence, consider a recent study of members of a Hadza tribe living on the Tanzanian savanna. It was found that sleep variability meant at any point during the night, 40 percent of adults were wakeful and able to call an alarm if they perceived danger. Researchers call this the “poorly sleeping grandparent hypothesis.”

Today we consider the sleep habits of teens and elders aberrant compared to adults,  pathologizing variations that came to us as a legacy of ancestral strength built by diversity.

Elders need to live as long as possible in order to pass along their earned experience  to the youngest generations. But elders are valuable to a community for another evolutionary reason— essentially living on or sacrificing themselves to benefit the young. At least that’s what  theoretical biologist Josh Mittledorf  speculates in Cracking the Age Code. He says our species long ago passed out of individual Darwinism into a sort of collective evolution as a way of protecting our communities from collapse.

According to Dr. Mittledorf, elders live longer or die younger based on biological responses to different community conditions.  Here’s how.  When times are very hard the population is at risk, particularly because it takes a great deal of exertion to get enough food to raise the young.  Elders feel the imperative to work hard and eat less for the good of their community. In many cases, they are also vitally needed to care for children.

In contrast, when times are easy the population is not at risk. Abundant food gained with less exertion means the young are likely to live to adulthood. Elders don’t feel compelled to do taxing work and they have plenty to eat. The community’s overall need is for more space to make room for an expanding population.

Let’s look at the messages an elder’s mind and body perceives in these two very different circumstances.

When times are hard, elders are needed by their families and communities. They sense they must thrive to keep their people going.  As research on aging tells us,  humans live longer in response to strenuous exertion, restricted calories, strong social connections, and a deep sense of purpose — precisely like these conditions.

But the imperative for survival may not be as strong when times are easy, food is abundant, and an elder perceives he or she isn’t essential to the family. Again, research on aging tells us that abundant food and minimal exertion, and perhaps a sense that we’re unnecessary or even in the way, leads to an earlier death.

We humans thrive when we are needed. That starts in our earliest years. Watch any toddler beam when he’s allowed to turn on the coffee grinder or run the hose over the car —- children yearn to take on real responsibility and to make a real difference to others. Strong social connections throughout life are so important that research affirms loneliness is as great a health risk as substance abuse, injury, and violence. In fact, chronic loneliness increases the chance of developing dementia by 64 percent and the risk of early death by 45 percent.  Our survival is linked to having an essential and valued role in the lives of others. 

Our whole beings know at the deepest levels that we live for one another. Time to embrace that, for the sake of our own lives and the sake of our collective lives.

“Your life and my life flow into each other as wave flows into wave, and unless there is peace and joy and freedom for you, there can be no real peace or joy or freedom for me. To see reality–not as we expect it to be but as it is–is to see that unless we live for each other and in and through each other, we do not really live very satisfactorily; that there can really be life only where there really is, in just this sense, love.”

~Frederick Buechner