Why Males Die Before Females

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In humans and many other animals, males age faster and die earlier than females.

New research suggests this might happen because of intense competition over sex.

After investigating about 20 different vertebrate species, researchers Tim Clutton-Brock and Kavita Isvaran at the University of Cambridge in England found the more polygynous a species was, the more likely their males were to age faster and die earlier than females.

The researchers explained that as competition among males for sex grows more intense, each male on average has less time to breed. As such, there is no strong incentive to evolve longevity among males in such species.

Since men age faster and die earlier than women, these findings suggest that "at the time when current human physiology evolved, perhaps around the late Stone Age, polygynous breeding was the norm," Clutton-Brock told LiveScience. "Of course, this doesn't provide any justification for polygyny or promiscuity now for males."

Clutton-Brock and Isvaran detailed their findings online Oct. 17 in the journal Proceedings of the Royal Society B.

Charles Q. Choi
Charles Q. Choi
Live Science Contributor
Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.