Mother's care linked to the evolution of longer lifespans

A mother’s love is a powerful force, shaping not just our childhood but potentially our entire lifespan. Recent research suggests a fascinating link between the depth of maternal care and the evolution of longer lifespans in both humans and animals.

Mystery of human longevity

Humans are an anomaly in the animal kingdom. We outlive many other mammals of comparable size, and scientists have long puzzled over the reasons behind our exceptional longevity.

Matthew Zipple, a Klarman Postdoctoral Fellow at Cornell University, believes the answer may lie in the unique bond between mother and child.

Zipple’s research, conducted alongside colleagues H. Kern Reeve and Orca Jimmy Peniston, challenges us to reconsider the significance of maternal care. “It’s one of the really mysterious things about humans, the fact that we live these super long lives as compared to so many other mammals,” said Zipple.

“What we’re putting forward is that a part of the explanation for our long lifespan is this other foundational aspect of our lives, which is the relationship between the mother and her child.”

Mother’s care and evolution

Zipple and his team propose that species in which offspring survival depends heavily on extended maternal care tend to evolve longer lifespans and slower reproductive rates. This pattern is evident in humans and a surprising array of other mammals, including hyenas, whales, and elephants.

“As we see these links between maternal survival and offspring fitness grow stronger, we see the evolution of animals having longer lives and reproducing less often – the same pattern we see in humans,” noted Zipple.

“And what’s nice about this model is that it’s general to mammals overall, because we know these links exist in other species outside of primates, like hyenas, whales and elephants.”

Motherhood’s influence

To test their hypothesis, the researchers developed a mathematical model that demonstrates the relationship between maternal survival, offspring fitness, and the pace of life.

This model, along with two additional empirical models, provides a framework for understanding how maternal care shapes the evolution of lifespan.

The team envisions that their models could be utilized by field ecologists to analyze long-term demographic data and predict the impact of maternal care on the evolution of various species.

“We hope we’ve made the model straightforward enough, that field ecologists can take their existing long-term demographic data that they’ve been collecting for decades and apply it to this model, and come up with this estimate of how much they expect mother’s maternal care to have shaped the evolution of their study system,” said Zipple.

Mother and grandmother hypothesis

The new research builds upon the existing Mother and Grandmother hypothesis, which posits that offspring have higher survival rates when their mothers and grandmothers are present in their lives.

While this theory has primarily been used to explain menopause in humans, Zipple’s work expands its scope, incorporating a wider range of ways in which maternal care influences offspring fitness.

The team’s models delve into the specific effects of a mother’s death after weaning but before the offspring’s sexual maturation. Zipple’s doctoral research on baboons and other primates revealed that such a loss can have profound negative impacts on offspring and even grand-offspring.

The power of mother’s care and love

For Zipple, whose research involved observing mother-infant interactions in baboons, the connection between motherhood and longevity resonates deeply.

“When you watch mothers and infants in nonhuman primates interact, you can just see in the faces of the infants that there’s nothing more important in the world than the presence of its mother.”

Zipple’s research reminds us of the profound and enduring influence of maternal love. It suggests that the bond between mother and child, a universal thread across the animal kingdom, may hold the key to unlocking the secrets of longevity and understanding the very essence of what it means to be human.

Part of the long-term aspiration of this line of research is linking maternal love to longevity – two mysterious and central aspects of what it is to be human.

The study is published in the journal Proceedings of the National Academy of Sciences (PNAS)

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