Have you kissed your grandmother today?
This is Sandra Tsing Loh with the Loh Down on Science.
Some anthropologists think Nana may have been responsible for increasing human lifespans.
See, like humans, female apes can have babies into their forties. But their lives don't extend much beyond that. Female humans, however, live well past childbearing age. Why the difference?
One idea? The Grandmother Hypothesis. It says that, during human evolution, grandmas helped gather food and care for grandkids. That freed moms up to have more babies. So grannies who lived long enough to be helpful had more grandkids, thus passing on their genes for longevity to more people.
It's a controversial idea, but a new study used mathematical modeling to try to measure the effect.
They defined grandmother age as (a-hem) 45. Then, using some specific assumptions about lifestyle, they ran the model.
And? Based only on help from grannies, human lifespan doubled in sixty thousand years!
That's why Nana is free to run off with Fabio her aerobics instructor well into menopause! She deserves it!