Polygamy is the key to a long life

Want to live a little longer? Get a second wife. New research suggests that men from polygamous cultures outlive those from monogamous ones.

After accounting for socioeconomic differences, men aged over 60 from 140 countries that practice polygamy to varying degrees lived on average 12% longer than men from 49 mostly monogamous nations, says Virpi Lummaa, an ecologist at the University of Sheffield, UK.

Lummaa presented her findings last week at the International Society for Behavioral Ecology’s annual meeting in Ithaca, New York.

Rather than a call to polygamy, the research might solve a long-standing puzzle in human biology: Why do men live so long?

This question only makes sense after asking the same for women, who - unlike nearly all other animals - live long past the menopause.

One answer seems to be a phenomenon called the grandmother effect. For every 10 years a woman survives past the menopause, she gains two additional grandchildren, Lummaa says. It seems that doting on and spoiling grandchildren aids their survival, as well as furthering some of their grandmother’s genes.

Men, by contrast, can reproduce well into their 60s and even 70s and 80s, and most researchers assumed this explained their longevity. But Lummaa and colleague Andy Russell wondered whether other factors explained the long lifespan of men, such as a grandfather effect.

To test this possibility, the team analysed church-gathered records for 25,000 Finns from the 18th and 19th centuries. People tended to move little, no one practiced contraception and the Lutheran Church enforced monogamy.
widowed men could remarry, and if they had children with their new wife, they fathered more kids, on average, than men who married once...