Why Females Outlive Males - Across Species

[kit_hung]

A global study of over 1,100 mammal and bird species reveals that lifespan differences between males and females are deeply rooted in biology. Female mammals live about 13% longer than males, while male birds outlive females by around 5%. This contrast is shaped by mating strategies, genetics, and parenting roles.


In mammals, intense competition for mates shortens male lifespans. Birds, often monogamous, show less stress and longer male survival. Genetics also play a role: mammalian females have two X chromosomes, offering protection from mutations, while in birds, males benefit from their chromosome setup.


Parental care matters too. In species where females invest more in raising offspring, they tend to live longer. Even in zoos, where environmental risks are low, lifespan gaps persist—proving biology is the main driver.


Ultimately, these differences aren’t just about lifestyle or environment. They’re evolutionary patterns that shape how long each sex lives—and they’re likely here to stay.

 

[gwolf666]

This study reveals something fascinating about how biology influences the differences in lifespan between males and females in mammals and birds. Personally, I think these patterns demonstrate the power of evolution to shape our lives, beyond external circumstances. I'm struck by the fact that, in mammals, competition for mates shortens the lifespan of males, while in birds, monogamy seems to favor greater male longevity. Genetics also plays a crucial role; females having two X chromosomes provides them with additional protection against mutations, reinforcing the idea that biology is deeply ingrained in our being. Furthermore, it's interesting that even in controlled environments like zoos, these differences persist, confirming that they are not solely a product of lifestyle or environment. Ultimately, these trends appear to be an intrinsic part of evolution and will likely continue to influence our lives in the future.