The menopause could be the reason some female whales live around 40 years longer than others, scientists have said.
Five species of whales go through menopause, the only other mammals to do so aside from humans.
Short-finned pilot whales, false killer whales, orcas, narwhals and beluga whales all stop releasing eggs.
Researchers say the menopause could have evolved to allow them to live long enough to care for extended family.
The experts – led by a University of Exeter team – suggested it allowed the whales to become grandmothers so they could take care of their families by sharing food or “babysitting”.
They said it meant some female whales, such as orcas (killer whales), end up living into their 80s, while their male counterparts are usually dead by 40.
Professor Darren Croft, of the University of Exeter and head of the Centre for Whale Research, said “the evolution of menopause and a long post-reproductive life could only happen in very specific circumstances” like a social structure where females are in “close contact with their offspring and grand-offspring”.
The study analysed data from scientific literature on 32 whale species.
It found the “male menopause” did not evolve in the same way as in females because male whales are not in the same social group as their children or grandchildren.
Professor Croft said: “So they (males) don’t actually have the opportunity to be able to provide help that late in life to their close kin, so evolution just favoured them to continue to reproduce until the end of life.”
Experts say menopause allows whales to survive long enough to ‘babysit’. Pic: iStock
He said previous work on orcas showed the life experience of post-reproductive females “is really crucial in dealing with environmental challenges in times of hardship”.
Read more from Sky News:
Two dogs die during ‘despicable’ 1,000-mile sled race
Eight children die after eating sea turtle meat
“We see just the same patterns in human societies – in hunter-gatherer societies – in times of drought,” added Professor Croft.”
“Or during times of social conflict, where people would turn to the elders of their community who would have had the experience (and) the knowledge.
“I think it is important to draw that parallel between humans and cetaceans in terms of the role that these older matriarchs in the case of tooth whales, or grandmothers in the case of human societies, are playing.”
