By Susan Milius
Male killer whale thirtysomethings appear to live longer when mom’s nearby, especially if mom has stopped reproducing. This survival bonus for mama’s boys could be the first evidence from nonhuman animals for an evolutionary advantage to living long after reproduction stops.
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In the Pacific Northwest, a male killer whale’s risk of disappearing, presumably from dying, seems to jump almost 14-fold if he’s older than 30 and his post-reproductive mom dies, says marine biologist Emma Foster of the University of Exeter in England. Daughters get a more modest fivefold boost, Foster and her colleagues report in the Sept. 14 Science.
Both sons and daughters typically spend their lives swimming with mom and other maternal relatives. Even though a female killer whale may stop having babies in her 30s or 40s, she can live into her 90s.