I learned something this week: only five species on Earth go through menopause.
As you might be aware, human women go through menopause. But interestingly, in all of the animal kingdom, only four other animals experience this transition. The other four are all whales with teeth.
Humans, belugas, narwhals, short-finned pilot whales and killer whales all experience menopause.
The question is why?
‘For menopause to make sense in evolutionary terms, a species needs both a reason to stop reproducing and a reason to live on afterwards,’ says scientist Dr. Sam Ellis, whose work added belugas and narwhals to the list in 2018.
In the case of killer whales, experts say the females go through menopause “because offspring of both genders stay with their mothers for life, her pod will eventually include her children and grandchildren.”
Thus females have a reason to stick around, even though they’re not the ones signing permission slips or administering Tylenol.
I learned this interesting fact because there’s new research on the benefits of younger members of the animal kingdom having a grandmother around. Scientists have discovered that post-menopausal grandmother whales are key to increasing the survival rate of their grandbaby whales. We’re talking survival — not just decorating Christmas cookies — but survival!
One proven example of the benefit of the postmenopausal whale grandma occurs when food is scarce.
“Research has shown that post-reproductive female killer whales are the most knowledgeable and provide an important leadership role for the group when foraging in salmon grounds,” said the study, published by the University of York.
The scientists analyzed 36 years of data gathered by the Center for Whale Research and Fisheries and Oceans Canada on two populations of killer whales. The populations included several whale family groups who live off the North West Pacific Coast of Canada and the U.S. They discovered that grandma knows stuff and she gets things done.
The studies show that once grandma isn’t dealing with maternity leave or nursing or the terrible twos (imagine a whale tantrum at the toy aisle of Target), she can focus on the big picture. Grandmother whales who stay with their families after they’re no longer reproducing can essentially employ a lifetime of skill sets to ensure their grandchildren don’t starve and know how to fold a fitted sheet properly.
It has been a long-standing evolutionary puzzle. Why do females of these species stop reproducing well before the end of life? But the new research shows that grandmothers are better able to help after they’re through the metaphorical weeds of raising small children. They also share the benefits of their lifetime of wisdom to make sure no one messes with their grandchildren.
I feel like we all know these grandmas. Whether they be killer whale or Welsh, beluga or Polish, narwhal or Irish, the benefit is the same.
Take note young moms — your mom can help in ways you probably didn’t realize. In fact, they can do so in key ways to help your little tykes thrive. And to older moms and grandmas, well, you already knew this. Just like you know how to find the good salmon.
Originally Published in Monroe News