{"id":180175,"date":"2025-11-14T10:49:10","date_gmt":"2025-11-14T10:49:10","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/180175\/"},"modified":"2025-11-14T10:49:10","modified_gmt":"2025-11-14T10:49:10","slug":"why-female-mammals-live-longer-than-males-but-female-birds-die-first","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/180175\/","title":{"rendered":"Why female mammals live longer than males but female birds die first"},"content":{"rendered":"

\u2018For no man at all can be living for ever, and we must be satisfied\u2019 \u2014 Maurya in Riders to the Sea\n <\/p>\n

The heroine of JM Synge\u2019s 1896 play, set in Inishmaan, has lost her husband and five sons to the sea. News arrives that a body has been washed up in Donegal. The clothing shows it\u2019s that of Michael, another son. Bartley, the last of Maurya\u2019s boys, is sailing to Connemara to sell a horse. He too perishes; a ghost-rider has been seen. “They\u2019re all gone now,” says the grief-stricken mother, “and there isn\u2019t anything more the sea can do to me”.<\/p>\n

Synge depicts a semi-pagan hunter-gatherer world \u2014 “It\u2019s little he (the priest) knows about the sea” etc.<\/p>\n

Michael\u2019s and Bartley\u2019s lives are cut short, but Cathleen and Nora, their \u2018gatherer\u2019 sisters, live on. Not just in Aran, but everywhere else, women live longer than men.<\/p>\n

Nor are such difference confined to humans… wild creatures also exhibit variations in lifespan between the sexes. The social insects provide spectacular examples. Female wasps and bees survive the winter but males don\u2019t. Honeybee drones die after participating in a nuptial flight but their mother, the queen, can live on for up to seven years.<\/p>\n

But stressful lifestyles can\u2019t always be held responsible; the trials and tribulations of the boardroom and bedroom hardly compare to those faced by Michael and Bartley. Something more fundamental is going on.<\/p>\n

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Why women live longer than men. A new study @ScienceAdvances<\/a> by an intl. research team led by Johanna St\u00e4rk and Fernando Colchero @MPI_EVA_Leipzig<\/a> traces the evolutionary roots of the #lifespan<\/a> gap between women and men. https:\/\/t.co\/SKVVM3ROZm<\/a> & https:\/\/t.co\/uHwqarWtXc<\/a> pic.twitter.com\/Rg0H9RdnQw<\/a><\/p>\n

\u2014 MPI-EVA Leipzig (@MPI_EVA_Leipzig) October 2, 2025<\/a><\/p><\/blockquote>\n

Scientists at Leipzig\u2019s Max Planck Institute have been studying longevity. Lead author Johanna St\u00e4rk says that differences in survival between the sexes “are deeply rooted in evolutionary history” and “can be observed in many animal species”.<\/p>\n

Lifestyle and environment are important, but genes also play a part.<\/p>\n

The Max Planck team measured the lifespans of 1,176 wild creatures. Female mammals, the analysis showed, live 13% longer on average than males. The reverse, however, is the case with birds; males last 5% longer.<\/p>\n

\"SexualSexual selection drives sex difference in adult life expectancy across mammals and birds<\/p>\n

To control for environmental factors, the researchers compared the longevities of animals in zoos with those of creatures fending for themselves in the wild. Pampered zoo inmates, fed and found, lead relatively stress-free lives. Their wild cousins\u2019 existence, by contrast, is often \u2018poor, nasty, brutish, and short\u2019.<\/p>\n

Not surprisingly, zoo-dwellers tend to live longest. However, differences in life expectancy between the sexes were less pronounced in zoos than in the wild.<\/p>\n

An individual\u2019s gender is determined by the sex chromosomes.<\/p>\n

A male mammal possesses both an X chromosome and a Y, whereas a female has two Xs.<\/p>\n

\"TheThe inheritance mechanism in birds is the opposite of the mammal one. It\u2019s the female who is \u2018heterogametic\u2019 \u2014 she has both a W and a Z chromosome. Male birds with their second Z, therefore, are less prone to suffer mutation damage than females. And so they live longer.<\/p>\n

Without a second X copy, the male bird is more vulnerable to damage by genetic mutations. The female is less exposed. If one of her Xs becomes impaired; she has the second copy as backup and harm is less likely to occur.<\/p>\n

This argument is supported by the bird findings. The inheritance mechanism in birds is the opposite of the mammal one. It\u2019s the female who is \u2018heterogametic\u2019 \u2014 she has both a W and a Z chromosome. Male birds with their second Z, therefore, are less prone to suffer mutation damage than females. And so they live longer.<\/p>\n