While menopause is a fact of life for middle - aged women , it ’s exceedingly rare in the creature realm . Including humans , there are now five mammal species that experience it .
AsForbesreveals , a new study in the journalScientific Reportsfinds that female narwhal and beluga giant also go through climacteric as they age . Until now , only three other species — humankind , killer giant , and short - fin pilot burner hulk — were make out to experience this procreative phase and carry on to live a foresightful clip subsequently .
Drawing from past inquiry , scientist at England ’s Exeter and York Universities and the Center for Whale Research in the U.S. determine out to discover whether menopause occur in other nautical mammal metal money . After examining the ovary of 16 species of whales and dolphins , they identifiednarwhalsandbeluga whalesas the only other animals that experience menopause .
Menopause refer to the period in which catamenia for good terminate and female are no longer able to procreate . Unlike world and the four aforementioned whale species , most female in the brute kingdom are able-bodied to continue reproducing well into old age . This group includeselephants , which have some of the longest life of any animal on Earth .
This is an oddity that has amaze scientist for years . " For change of life to make sense in evolutionary terms , a species take both a reason to block reproducing and a reasonableness to live on afterwards , " one of the new work ’s writer , Samuel Ellis of the University of Exeter , tellsForbes .
late research on Orcinus orca whales ( which were not include in the scope of this sketch ) suggest that change of life is linked to granny whales ’ relationships with their new offspring — a theory call the “ grandmother hypothesis . ” Ellis take down that “ both male and female [ killer whale ] materialisation stick around with their mother for life — so as a female historic period , her chemical group turn back more and more of her children and grandchild . ”
The giant ’s tiddler and grandchildren are all competing for resources such as nutrient , so that may be why menopause steps in to close down her generative cycle . It ’s believe that grandmother giant continue to exist on well after menopause — unlike other species that go through something like menopause , but choke shortly after — because they provide all important cognition to their tight - knit groups of descendants . The authors of the latest study say there is also evidence that our human antecedent followed similar societal patterns .
[ h / tForbes ]
