Featured Research

from universities, journals, and other organizations

Evolutionary Forces Explain Why Women Live Longer Than Men

Date:
May 10, 2006
Source:
University of Michigan
Summary:
Despite research efforts to find modern factors that would explain the different life expectancies of men and women, the gap is actually ancient and universal, according to University of Michigan researchers.

Despite research efforts to find modern factors that would explain the different life expectancies of men and women, the gap is actually ancient and universal, according to University of Michigan researchers.

"Women live longer in almost every country, and the sex difference in lifespan has been recognized since at least the mid-18th century," said Daniel J. Kruger, a research scientist in the U-M School of Public Health and the Institute for Social Research. "It isn't a recent trend; it originates from our deep evolutionary history."

This skewed mortality isn't even unique to our species; the men come up short in common chimps and many other species, Kruger added.

Kruger and co-author Randolph Nesse, a professor of psychology and psychiatry and director of the Evolution and Human Adaptation Program, argue that the difference in life expectancy stems from the biological imperative of attracting mates.

"This whole pattern is a result of sexual selection and the roles that males and females play in reproduction," Kruger said, "Females generally invest more in offspring than males and are more limited in offspring quantity, thus males typically compete with each other to attract and retain female partners."

For example, in common chimps, the greatest difference in mortality rates for males and females occurs at about 13 years of age, when the males are just entering the breeding scene and competing aggressively for social status and females.

From the tail of the peacock to the blinged-out SUV, males compete aggressively for female attention, and that costs them something. In nature, it means riskier physiology and behavior for the males, such as putting more resources into flashy plumage or engaging in physical sparring.

And even in modern life, where most dueling is a form of entertainment, male behavior and physiology is shortening their lifespans relative to women, Kruger said. In fact, modern lifestyles are actually exacerbating the gap between male and female life expectancies.

Male physiology, shaped by eons of sexual competition, is putting the guys at a disadvantage in longevity. Male immune systems are somewhat weaker, and their bodies are less able to process the fat they eat, Kruger said. And behavioral causes---smoking, overeating, reckless driving, violence---set men apart from most women. "Because mortality rates in general are going down, behavioral causes of death are ever more prevalent," Kruger said.

Looking at human mortality rates sliced by socioeconomic status shows that the gender gap is affected by social standing. Human males in lower socio-economic levels tend to have higher mortality rates than their higher-status peers. The impact of social standing is greater on male mortality than on female mortality, Kruger noted, partially because males who have a relatively lower status or lack a mate engage in a riskier pattern of behaviors in an attempt to get ahead, he said.

The paper "An evolutionary life-history framework for understanding sex differences in human mortality rates," appears in the spring 2006 edition of Human Nature.

For more information on Kruger, visit: http://www-personal.umich.edu/~kruger/
For more on Nesse: http://www-personal.umich.edu/~nesse/


Story Source:

The above story is based on materials provided by University of Michigan. Note: Materials may be edited for content and length.


Cite This Page:

University of Michigan. "Evolutionary Forces Explain Why Women Live Longer Than Men." ScienceDaily. ScienceDaily, 10 May 2006. <www.sciencedaily.com/releases/2006/05/060510091521.htm>.
University of Michigan. (2006, May 10). Evolutionary Forces Explain Why Women Live Longer Than Men. ScienceDaily. Retrieved August 19, 2014 from www.sciencedaily.com/releases/2006/05/060510091521.htm
University of Michigan. "Evolutionary Forces Explain Why Women Live Longer Than Men." ScienceDaily. www.sciencedaily.com/releases/2006/05/060510091521.htm (accessed August 19, 2014).

Share This




More Plants & Animals News

Tuesday, August 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Awesome New Camouflage Sheet Was Inspired By Octopus Skin

Newsy (Aug. 19, 2014) — Scientists have developed a new device that mimics the way octopuses blend in with their surroundings to hide from dangerous predators. Video provided by Newsy
Powered by NewsLook.com
Disquieting Times for Malaysia's 'fish Listeners'

Disquieting Times for Malaysia's 'fish Listeners'

AFP (Aug. 19, 2014) — Malaysia's last "fish listeners" -- practitioners of a dying local art of listening underwater to locate their quarry -- try to keep the ancient technique alive in the face of industrial trawling and the depletion of stocks. Duration: 02:29 Video provided by AFP
Powered by NewsLook.com
USDA Cracks Down On Imports From Foreign Puppy Mills

USDA Cracks Down On Imports From Foreign Puppy Mills

Newsy (Aug. 18, 2014) — New USDA measures to regulate dog imports aim to crack down on buying dogs from overseas puppy mills. Video provided by Newsy
Powered by NewsLook.com
Bone Marrow Drug Regrows Hair In Some Alopecia Patients

Bone Marrow Drug Regrows Hair In Some Alopecia Patients

Newsy (Aug. 18, 2014) — Researchers performed an experiment using an FDA-approved drug known as ruxolitinib. They found it to be successful in the majority of patients. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins