Science Studies Why Female Mammals Live Longer Than Males

Based on a new report, a group of researchers recently found that, much like us humans, wild female mammals tend to live significantly longer than their male counterparts.

Why Females Live Longer Than Males

Led by scientists from the University of Lyon 1 and published in the scientific journal Proceedings of the National Academy of Sciences, the study looked at the lifespans of around 101 different species, discovering that females tend to live longer than males by around 18 percent for more than 60 percent of the animals that were included in the study. And when it comes to humans, females tend to live around 7.8 percent longer. Per the researchers, this is not because of sexes aging at different rates, but because females tend to have an average lower risk of mortality when they reach adulthood compared to males.

And while it was unclear as to why this is so, the authors suggest that complex interactions between the local environmental conditions and sex-specific costs of reproduction play a big factor.

“We've known for a long time that women generally live longer than men, but were surprised to find that the differences in lifespan between the sexes was even more pronounced in wild mammals than in humans. This could be either because females are naturally able to live longer, or that female mortality drops compared with males,” Professor Tamás Székely, one of the study authors and from the Milner Center for Evolution at the University of Bath, said.

“For example, lionesses live at least 50 percent longer in the wild than male lions. Female lions live together in a pride, where sisters, mothers and daughters hunt together and look after each other, whereas adult male lions often live alone or with their brother and therefore don't have the same support network,” Székely added.

Furthermore, one other possible explanation is that males usually provide all of the parental care, like in birds. As such, the researchers plan to study animals in the zoo, where factors such as predator or competition for food or mates won’t be a competing factor. This will give them a more definite measure of life expectancy between males and females.

Bonobo apes, primates unique to Congo and humankind's closest relativ Bonobo apes, primates unique to Congo and humankind's closest relative, groom one another at a sanctuary just outside the capital Kinshasa, October 31, 2006. Scientifically named Pan paniscus, but more commonly known as pygmy chimpanzees, bonobos share 98.4% of their genetic make-up with humans, but are at risk of extinction due to more than a decade of conflict in Central Africa. Finbarr O'Reilly/Reuters