Why Do Men Die So Much Earlier Than Women?
A new study offers fresh insights on why men die younger than women.
Posted October 9, 2025 | Reviewed by Abigail Fagan
It is a quite striking finding: Worldwide, men on average die 5.4 years earlier than women. While the exact number of years differs somewhat between countries, it is the same across the whole world and many different cultures.
For example, in the US, the death gap is 5.8 years in favor of women, with the main factors contributing to men dying earlier than women being unintentional injuries, diabetes, suicide , homicide, and heart disease ( Yan and co-workers, 2024 ).
A new study takes an evolutionary perspective to understand why men die earlier than women
A new study published October 1st, 2025, in the journal Science Advances, used an evolutionary perspective to better understand why there is such a large death gap between men and women ( Staerk and co-workers, 2025 ). The study, entitled “ Sexual selection drives sex difference in adult life expectancy across mammals and birds,” focused on the question of whether a death age gap between males and females can also be observed in non-human animals. To this end, the scientists analyzed data on adult life expectancy from 528 mammalian species and 648 bird species that were kept in zoos or lived in the wild.
Like human men, other male mammals often die younger than other female mammals
The findings for the 528 mammalian species were similar to what is observed in humans. In 381 out of 528 mammalian species (72%), male animals died younger than female animals. Only 5% had a death gap in favor of males, while the remaining species did not show pronounced differences between male and female animals regarding life expectancy. Nearly 40% of mammalian species had a very large death age gap in favor of females. Across species, the death age gap between male and female mammals was 12% of the lifetime. Chimpanzees and gorillas, our closest primate relatives, showed similar death age gaps in favor of females, like humans. This shows that males dying younger than females clearly is the rule, not the exception, in mammals. It also shows that the death gap is not uniquely human, but maybe partly the consequence of larger evolutionary patterns.
Interestingly, for birds, a reverse, but weaker, pattern was found. Overall, 438 out of 648 bird species (68%) showed a death gap in favor of males. Across species, the death gap between male and female birds was 5% of their lifetime.
How can the result pattern be explained?
The scientists then performed further statistical analysis to explain this result pattern.
The factor that explained most of the result pattern was whether a species was monogamous or non-monogamous. For example, in animal species that lived in zoos, females had a 15% lifetime increase over males in species that were not monogamous. In monogamous species, there was almost no death age gap. This finding is in line with the so-called sexual selection hypothesis that suggests that males may show risky behavior that may endanger survival (e.g., fighting with other males) to mate with females. This effect is particularly pronounced in species that are not monogamous. In these species, the competition between males is more intense than in monogamous species, leading to more risky behavior and earlier death.
A second factor that explained some of the results was size differences between male and female animals. In species in which male animals were much larger than female animals, a larger death age gap occurred. This finding is in line with the first finding, as species with very large size differences between males and females (think of gorillas or walruses) are often non-monogamous.
Moreover, female care for offspring was a factor that drove the age gap. Parents generally tend to take fewer risks, as they are responsible for their children, which may explain why being a parent increases life expectancy.
What can we learn about why men die so much younger than women from the results of the study?
The scientists suggested that their findings may be helpful to explain why there are such strong and consistent differences between men and women in life expectancy. The female advantage in lifetime length is not something uniquely human but is part of a wider pattern in mammalian evolution. It is well known that men show more risky behavior than women, such as high-speed driving, drinking alcohol , or using drugs, which can shorten their lifespan.
Many of the factors mentioned above that contribute to the death age gap (unintentional injuries, diabetes, suicide, homicide, and heart disease) can be positively influenced by lifestyle choices. As the study suggested that care for offspring increases the life span due to less risky behavior, becoming a dad may be a great way to reduce that death age gap.
Facebook image: Krakenimages.com / Shutterstock
Staerk, J., Conde, D. A., Tidière, M., Lemaître, J. F., Liker, A., Vági, B., Pavard, S., Giraudeau, M., Smeele, S. Q., Vincze, O., Ronget, V., da Silva, R., Pereboom, Z., Bertelsen, M. F., Gaillard, J. M., Székely, T., & Colchero, F. (2025). Sexual selection drives sex difference in adult life expectancy across mammals and birds. Science advances , 11(40), eady8433. https://doi.org/10.1126/sciadv.ady8433
Yan, B. W., Arias, E., Geller, A. C., Miller, D. R., Kochanek, K. D., & Koh, H. K. (2024). Widening Gender Gap in Life Expectancy in the US, 2010-2021. JAMA internal medicine , 184(1), 108–110. https://doi.org/10.1001/jamainternmed.2023.6041
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Sebastian Ocklenburg, Ph.D., is a professor for research methods in psychology at the Department of Psychology at MSH Medical School in Hamburg, Germany. His research focuses on left-handedness and brain asymmetries.
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This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.