Amazing stuff! However, this research is dated, published in October 2025!
" ... In birds, it’s the reverse."
"Females, whether they be human or some other type of mammal, like primates or even whales, tend to outlive men by an average of 5.4 years. ..."
"To the point
- Mammals vs birds: Among the 1,176 species studied, female mammals live on average 13 percent longer than males, while among birds, males live about five percent longer than females.
- Mating strategies play a role: In species with strong competition for mates – as is the case with most mammals – males die earlier. In monogamous species, such as many birds, males often live longer.
- Findings from zoos: Sex differences are more pronounced in wild populations than in zoos. This suggests that both genetic and environmental factors contribute to the discrepancy in life expectancy.
...
An international team ... conducted the most comprehensive analysis of sex differences in lifespan across mammals and birds to date. ...
Across mammals, females usually live longer—for instance, in baboons and gorillas females often outlive males.
Yet this pattern is not universal: in many birds, insects, and reptiles, males are the longer-lived sex.
One genetic explanation, the heterogametic sex hypothesis, points to differences in sex chromosomes. In mammals, females have two X chromosomes, while males have only one X and one Y (making them the heterogametic sex). ...
Still, there was remarkable variation with many exceptions. “Some species showed the opposite of the expected pattern,” ... “For example, in many birds of prey, females are both larger and longer-lived than males. So sex chromosomes can only be part of the story.” ...
In addition to genetics, reproductive strategies also play a role. Through sexual selection, males in particular develop conspicuous characteristics such as colorful plumage, weapons, or large body size, which increase reproductive success but can shorten lifespan.
The new study supports this assumption: In polygamous mammals with strong competition, males generally die earlier than females.
Many birds, on the other hand, are monogamous, which means that competitive pressure is lower and males often live longer.
Overall, the differences were smallest in monogamous species, while polygamy and pronounced size differences were associated with a more pronounced advantage for females. ...
Parental care also plays a role. The researchers found evidence that the sex that invests more in raising offspring—in mammals, this is often the females—tends to live longer. In long-lived species such as primates, this is likely to be a selective advantage: females survive until their offspring are independent or sexually mature.
Zoo life reduces—but does not erase—lifespan gaps
A long-standing idea is that environmental pressures—such as predation, pathogens, or harsh climates—drive the observed gaps between males and females. To test this, the researchers turned to zoo populations, where such pressures are largely absent. They found that lifespan gaps persisted even under these protected conditions.
Comparing zoo and wild populations showed that the gaps were often smaller in zoos but rarely disappeared—mirroring the human case, where advances in medicine and living conditions have narrowed but not eliminated the lifespan gap.
The findings suggest that sex differences in lifespan are deeply rooted in evolutionary processes—shaped by sexual selection and parental investment and that genetic differences in the sex determination system may also play a role. ..."
From the abstract:
"Across human cultures and historical periods, women, on average, live longer than men, a pattern best understood from a comparative evolutionary perspective. Here, we analyzed adult life expectancy in 528 mammal and 648 bird species in zoos. Like humans, 72% of mammals exhibited a female life expectancy advantage, while 68% of birds showed a male advantage, as expected from the harmful effects of sex chromosomes described by the heterogametic sex hypothesis.
Yet, sex differences varied widely.
In zoos, we found strong evidence that this variation generally correlated with both the mating system and sexual size dimorphism.
Although with weaker evidence, the patterns remained consistent in populations from the wild, with an even larger effect of the mating system.
Thus, even in zoos, where environmental pressures are largely reduced, precopulatory sexual selection seems to play a fundamental role in shaping sex differences in life expectancy in mammals and birds."
Why women live longer than men - evolutionary insights on longevity (original news release, October 2025)
Sexual selection drives sex difference in adult life expectancy across mammals and birds (open access) "Study traces the evolutionary roots of the lifespan gap between women and men"
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