The findings reveal that females of these whale types that experience menopause live around 40 years longer than other female whales of a similar size.By living longer without extending their “reproductive life-span” (the years in which they reproduce), these females have more years to help their grandchildren and kids, without increasing the “overlap” period when they contend with their daughters by breeding and raising calves at the same time. This brand-new research shows that– in spite of being separated by 90 million years of development– whales and people show extremely comparable life histories, which have progressed independently.The study was carried out by the universities of Exeter and York, and the Center for Whale Research.A post-reproductive mom killer whale (K14) leading her young child (K42) and adult son (K26).”Menopause is known to exist in five types of toothed whales: short-finned pilot whales, incorrect killer whales, killer whales, narwhals, and beluga whales.”Despite these distinctions, our outcomes reveal that humans and toothed whales show convergent life history– just like in people, menopause in toothed whales evolved by selection to increase the total lifespan without likewise extending their reproductive lifespan.
New research shows that some whale species have actually evolved to experience menopause and live longer, comparable to human beings, to better support their households. This research study highlights the evolutionary parallels in extended life expectancy post-reproduction in between human beings and whales.New research study suggests that women in certain whale species have actually developed to have significantly longer life-spans in order to take care of their families.The study focussed on 5 whale types that– in addition to people– are the only mammals known to go through menopause. The findings show that females of these whale species that experience menopause live around 40 years longer than other female whales of a comparable size.By living longer without extending their “reproductive lifespan” (the years in which they breed), these females have more years to help their children and grandchildren, without increasing the “overlap” duration when they take on their children by breeding and raising calves at the very same time. This new research shows that– regardless of being separated by 90 million years of development– whales and people show remarkably comparable biography, which have actually progressed independently.The study was performed by the universities of Exeter and York, and the Center for Whale Research.A post-reproductive mother killer whale (K14) leading her young kid (K42) and adult child (K26). Credit: David Ellifrit, Center for Whale Research. Reference Permit NMFS-27038Study Origins and Evolutionary Insights”The process of evolution prefers traits and behaviors by which an animal passes its genes to future generations,” stated lead author Dr Sam Ellis, from the University of Exeter. “The most obvious way for a female to do this is to reproduce for the whole life expectancy– and this is what happens in almost all animal types. There are more than 5,000 mammal types, and just 6 are understood to go through menopause. The question is: how and why did menopause progress? Our research study supplies a few of the answers to this fascinating puzzle.”Menopause is understood to exist in five types of toothed whales: short-finned pilot whales, false killer whales, killer whales, narwhals, and beluga whales. As outliving women of other similar-sized species, females in these five species outlast the males of their own types. For example, female killer whales can live into their 80s, while males are generally dead by 40. Evolutionary Conditions for Menopause”The development of menopause and a long post-reproductive life could only occur in very specific situations,” said Professor Darren Croft, of the University of Exeter and Executive Director at the Center for Whale Research “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 women should have a chance to assist in manner ins which improve the survival opportunities of their family. For example, female toothed whales are known to share food and utilize their knowledge to guide the group to find food when it is in brief supply.”Post reproductive mother (L5) and boy. Credit: David Ellifrit, Center for Whale Research. Recommendation Permit NMFS-27038Professor Dan Franks, from the University of York, said: “Previous research study on menopause development has actually tended to concentrate on single types, generally human beings or killer whales. This research study is the very first to cross a number of types, enabled by the recent discovery of menopause in numerous types of toothed whales. Our study supplies evidence that menopause developed by broadening female lifespan beyond their reproductive years, instead of from decreased reproductive life expectancy. This is a question that has actually long been asked in sociology, but can just be directly addressed with a comparative research study.”Commenting on parallels with the evolution of menopause in people, Professor Croft added: “Its interesting that we share this life history with a taxonomic group were so various from.”Despite these distinctions, our results reveal that humans and toothed whales show convergent biography– just like in humans, menopause in toothed whales progressed by selection to increase the total life expectancy without also extending their reproductive life expectancy.”Reference: “The evolution of menopause in toothed whales” by Samuel Ellis, Daniel W. Franks, Mia Lybkær Kronborg Nielsen, Michael N. Weiss and Darren P. Croft, 13 March 2024, Nature.DOI: 10.1038/ s41586-024-07159-9The research study was funded by the Leverhulme Trust and the Natural Environment Research Council (NERC).