BOB HIRSHON (host):
The meaning of menopause. I’m Bob Hirshon and this is Science Update.
Menopause, or declining fertility with age, is extremely rare in the mammal world. According to evolutionary biologist Michael Cant at the University of Exeter in England, only female humans, killer whales and pilot whales live for a long time after they stop reproducing.
MICHAEL CANT (University of Exeter):
Elephants, for instance, breed into their 60s and blue whales breed into their 90s. Fertility declines as they get older but only at the same rate that everything else is declining.
So what do women have in common with female pilot whales and killer whales? Well, according to Cant, in all three species, females live in social groups in which they become more and more closely related to the group over time. He suspects in these species, those who cared for their grandchildren instead of producing more children themselves insured greater survival of their genes. I’m Bob Hirshon, for AAAS, the science society.