In difficult times, having multiple husbands can be an advantage

August 14, 2019

It is well known that men benefit reproductively from having multiple spouses, but the reasons why women might benefit from multiple marriages are not as clear. Women, as a result of pregnancy and lactation, can't reproduce as fast as males.

But new research by the University of California, Davis, challenges evolutionary-derived sexual stereotypes about men and women, finding that multiple spouses can be good for women too.

"We can't pin down the exact reasons for this finding, but our work (together with suggestions of others) suggests that marrying multiply may be a wise strategy for women where the necessities of life are hard, and where men's economic productivity and health can vary radically over their lifetime due to the challenging environmental conditions," said the lead researcher, Monique Borgerhoff Mulder, UC Davis professor of anthropology.

Women can buffer themselves against effects of the economy

Researchers infer that by acquiring multiple spouses, women can buffer themselves against economic and social crises, and more effectively keep their children alive.

Borgerhoff Mulder collected data on births, deaths, marriages and divorces of all households in a western Tanzanian village over two decades. A longitudinal study like this is "much more reliable than records collected retrospectively," said the study's co-author, Cody Ross, currently a postdoctoral fellow at the Max Planck Institute for Evolutionary Anthropology, Leipzig.

Working with the demographic data, Ross found that women who moved from spouse to spouse tended to have more surviving children, controlling for the number of years they had been married. Men by contrast, again controlling for their number of married years, tended to produce fewer surviving children with the individual women they married over their lives.

Researchers collected data on nearly 2,000 individuals living in a small village at the north end of the Rukwa Valley, in an area adjacent to floodplains and woodlands now designated as Katavi National Park. The people who live there are of Pimbwe and related Bantu ethnicity. The Pimbwe people have a long history of hunting, fishing, and farming cassava and maize. They also gather honey, brew beer and conduct small business. But crop yields are unreliable owing to unpredictable rainfall, poor soil conditions, agricultural pests and theft.

The latest paper, published Aug. 14 in Proceedings of the Royal Society B, represents a culmination of two decades of work by Borgerhoff Mulder, who has written extensively about the lives of men and women in this small village in western Tanzania where she conducts anthropological and demographic research.

"As evolutionary biologists we measure benefit in terms of numbers of surviving children produced -- still a key currency in rural Africa," explained Borgerhoff Mulder. "... it bears emphasizing that in many parts of rural Africa reproductive inequality among women emerges not from reproductive suppression as in some other highly social mammals ... but more likely from direct competition among women for access to resources." These resources include high-quality spouses, multiple caretakers to help around the house and farm, and (at least in this particular cultural context) helpful in-laws, she said.

Marriage in the Pimbwe culture is informal -- defined as sexual partners living together. Accordingly, "divorce is easy, and can be initiated by either partner," as both Borgerhoff Mulder and early 20th century missionary visitors to the area have observed. Both men and women may have more sexual partners than marriage partners, but sexual partnerships are quickly recognized as marriages, researchers said.

University of California - Davis

Related Science Articles from Brightsurf:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.

Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.

Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.

Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.

World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.

PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.

Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.

Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.

Read More: Science News and Science Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to