Grandmothers and Evolution
What does it mean to have a grandma? Grandmothers’ love is a significant part of childhood memories and joys for many of us. Visits to grandma’s house, special treats, being allowed to do things mom and dad would never let us get away with…there is an unexplainable magic about a grandma. We adore them when we are children, and as we (and they) grow older, we often begin to view them as valuable sources of wisdom and experience in a way that goes beyond what our parents can offer us.
Aside from the unique love, support and fun that only a grandma can bring, research suggests that grandmothers have actually played a crucial evolutionary role in terms of human longevity. That is to say, the value of grandmothers is a key reason that humans have evolved to live past their childbearing years—and in fact, why human females become infertile later in life.
Given the level of care a baby requires, and the length of time during which that care is required, having multiple young children means a lot of work for a mother—and competition for the mother’s attention. Many baby animals are able to survive on their own within one year, leaving the mother free to care for new youngsters each year. But the human child-rearing process is much more complicated.
When women become infertile and are no longer having children of their own, this means they are able to lend a hand with feeding and caring for their grandchildren. This idea is called the “grandmother hypothesis.” In early human history, having mom’s and dad’s mothers around dramatically increased the rate of survival of infants, and was the beginning of the beloved role of grandma.
A study published by the Royal Society in 2012 provided a mathematical model for the “grandmother hypothesis.” The full study is available online and an article published by the Smithsonian gives interpretation and analysis.