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Menopause could clarify why some whale live round 40 years longer than others, scientists have stated.
Apart from people, whales are the only mammals that go through menopause.
This pure organic course of is thought to exist in simply 5 species of toothed whale: short-finned pilot whales, false killer whales, killer whales, narwhals and beluga whales.
The researchers stated the findings, revealed in the journal Nature, recommend that menopause could have developed to allow these whales to survive lengthy sufficient to turn out to be grandmothers – to allow them to take care of their households by sharing meals or “babysitting”.
Being post-menopausal additionally means these species can have lengthy lives with out competing with their daughters or granddaughters for mates, scientists say.
Professor Darren Croft, of the University of Exeter and govt director at the Centre for Whale Research, stated: “The evolution of menopause and a long post-reproductive life could only happen in very specific circumstances.
“Firstly, a species must have a social structure in which females spend their lives in close contact with their offspring and grand-offspring.
“Secondly, the females must have an opportunity to help in ways that improve the survival chances of their family.
“For example, female toothed whales are known to share food and use their knowledge to guide the group to find food when it is in short supply.”
Female killer whales can live into their 80s, whereas males are sometimes useless by 40
(Getty)
The researchers analysed information from scientific literature to assemble the life historical past of 32 whale species.
The group stated “male menopause” didn’t evolve in the similar manner because male whales will not be in the similar social group as their kids or grandchildren.
Professor Croft stated: “So they (male whales) 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.”
But this additionally means females usually outlive the males of their very own species.
For instance, the researchers stated, feminine killer whales can live into their 80s, whereas males are sometimes useless by 40.
They stated that regardless of being separated by 90 million years of evolution, whales and people have “remarkably similar life histories which have evolved independently”.
The examine was funded by the Leverhulme Trust and the Natural Environment Research Council (NERC).
Prof Croft stated earlier work on killer whale populations has proven the life expertise of post-reproductive females “is really crucial in dealing with environmental challenges in times of hardship”.
He stated: “We see just the same patterns in human societies – in hunter-gatherer societies – in times of drought, or in 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.”
Lead writer Dr Sam Ellis, from the University of Exeter, added: “There are more than 5,000 mammal species, and only six are known to go through menopause.
“So the question is: how and why did menopause evolve?
“Our study provides some of the answers to this fascinating puzzle.”
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