It has been long established that women generally live longer than men.
Conventional wisdom says that the main reason for this is that men tend to engage in more “risky behaviors” than women. That may be true, and it’s part of the equation, but a recent study suggests it is more than that.
Scientists seem to think that there is evolution and natural selection at play. Unlike other egg-laying species that give birth to dozens, hundreds, or even thousands of offspring at a time, mammals and particularly primates and humans, have long gestations and single births.
Therefore, a longer lifespan for women is a way of ensuring the survival of the species. Women live longer, so they can theoretically have more children.
Among humans, women’s lifespan is almost 8% on average longer than men’s lifespan.
But among wild mammals, females in 60% of the studied species have, on average, 18.6% longer lifespans. The ratio is considerably different for different groups of mammals.
“For example, lionesses live at least 50% longer in the wild than male lions,” said Tamás Székely, from the University of Bath, one of the authors of the study.
The researchers hope that by studying the lifespan/gender gap in other mammalian species, they can get some clearer insights into why human females tend to outlive males.
In the past 200 years, the average life expectancy of humans has more than doubled due to improved living conditions and advances in medicine. Yet women continue to live longer than men, suggesting that biological differences also have a role.
According to the U.S. Centers for Disease Control, the average American man will live to age 76, while the average woman in America will live to age 81. Women can also expect to be healthier than men in their senior years. Experts have said the gap is due to a combination of biological as well as social differences.
Men’s hormone testosterone is linked to a decrease in their immune system and risk of cardiovascular diseases as they age.
It is also linked to risky behavior: smoking, drinking, and unhealthy eating habits.
If diagnosed, men are less likely than women to follow their doctor’s advice. Statistics show that men are more likely to take life-threatening risks and to die in car accidents or from physical altercations and gun violence.
Authors of the new study say the differences between male and female longevity are shaped by complex interactions between local environmental conditions and sex-specific reproductive biology.
They say that more research is likely to provide “innovative insights into the evolutionary roots and physiology underlying aging in both sexes.”