Study: Women live longer if they have grandchildren, men live longer if they have multiple wives

From Fox News:

Some men may think one is bad enough. But a study suggests the key to a long life may be to get a second wife.

Researchers from the U.K.'s University of Sheffield looked at men older than 60 from 140 countries that practice polygamy and found that they lived an average of 12 percent longer than men from 49 monogamous nations, according to a report from the Times of India.

The study's findings were presented last week at the International Society for Behavioral Ecology’s annual meetingin Ithaca, New York, according to the report.

Researchers looked to previous research on women to answer why polygamous men live longer and chalk it up to a variation of the "grandmother effect."

Scientists believe women, who live considerably longer post-menopause than other mammals, do so because the longer they live the more grandchildren they have to dote on. Caring for grandchildren, it seems, gives women a reason to live long after they're no longer able to reproduce.

Doting on grandchildren, however, does not have the same life-lengthening benefits for men. But men are able to reproduce into their 60s, 70s and 80s. So it would seem, researchers said, that polygamous men experience a sort of father effect, meaning, the more wives they have, the more children they father. Fathering children gives them a reason to continue living longer than monogamous men who often stop fathering children at much earlier ages, researchers concluded.