“They do this by helping to increase the survival of their older sons, which in turn increases the number of grandchildren fathered by their sons,” Darren Croft, a senior lecturer in animal behavior at the University of Exeter, told Discovery News. “Through this process, evolution favors females that live longer after their menopause. This explains why female killer whales have evolved the longest lifespan after menopause of all non-human animals.”
Menopause is, however, extremely rare in the animal kingdom, with only a handful of non-human animal females also going through this “change of life.” Stone said “prolonged life spans probably are a major factor.” The other animals may simply not live long enough to evolve menopause.
Regarding so-called “male menopause,” Singh said, “I think menopause in men is not a real menopause but kind of a joke and it refers to lack of interest in sex!”
Interested or not in sex, the majority of men do remain fertile throughout the rest of their adult lives.
The good news for women is that such research might, in future, allow doctors to reverse menopause.
“The new theory opens up the possibility that menopause could be delayed by hormonal treatment," Singh explained. "This would be a good thing for career women starting a family late in life.”
Younger men pairing with older women -- so-called cougars -- could also work wonders too.
Over time, if the cougar trend continues, it could affect how menopause evolves, perhaps prolonging when it happens, “provided these younger men/older women couples reproduce,” Singh said.