Working underwater off the Zambian shores of Lake Tanganyika in Africa, the researchers examined how males respond to changes in social position in the cichlid fish, Neolamprologus pulcher. This species lives in permanent social groups made up of a dominant male and female breeding pair and subordinate males and females that help this pair look after young and defend territory.

By removing the male breeders, researchers created vacancies and provided an opportunity for subordinate males to rise through the ranks.

“Hormones and genetic relationships didn’t necessarily determine who gets to be top dog,” says Sigal Balshine, the senior author on the study and an associate professor in the department of Psychology, Neuroscience & Behaviour. “Most folks would have thought that how aggressive you are, how big and powerful you are or how much testosterone you have might be important in understanding status change and dominance rankings. Our study combined several approaches to show that simply isn’t the case – instead, the female and the social landscape are key.”

McMaster University, a world-renowned, research-intensive university, fosters a culture of innovation, and a commitment to discovery and learning in teaching, research and scholarship. Based in Hamilton, the University, one of only four Canadian universities to be listed on the Top 100 universities in the world, has a student population of more than 23,000, and an alumni population of more than 130,000 in 128 countries.

For more information, please contact:

John Fitzpatrick
Department of Biology
McMaster University
905-525-9140, ext. 23237
fitzpajl@mcmaster.ca

Sigal Balshine
Department of Psychology, Neuroscience & Behaviour
McMaster University
905-525-9140, ext. 23024
sigal@mcmaster.ca

Michelle Donovan
Public Relations Manager: Broadcast Media
McMaster University
905-525-9140 ext. 22869
donovam@mcmaster.ca

Jane Christmas
Manager, Public & Media Relations
McMaster University
905-525-9140, ext. 27988
chrisja@mcmaster.ca