"I think there could be parallels in human social status change," Fernald says. "For example, if you're in a situation that's socially awkward, it may influence how well you can speak, or your sense of yourself may be altered. Those reactions have to have some kind of cellular underpinnings."
The study also contributes to a growing body of scientific evidence that fish are more than mindless creatures that instinctively swim about in search of food and mates. "Our study shows that the male cichlid is obviously interacting with the world around it," says Burmeister, a former postdoctoral fellow in the Fernald lab, now assistant professor of biology at the University of North Carolina-Chapel Hill. "The subordinate male is responding to the absence of another individual, so he has to have some kind of understanding of what their relationship was in the past and what it is now. This implies a cognitive ability to process complex information, which is much more that we usually think of in fish."
The PloS Biology study is the latest in a series of experiments from the Fernald lab on the behavior of Astatotilapia (Haplochromis) burtoni--one of hundreds of cichlid species that inhabit Lake Tanganyika and other freshwater lakes in East Africa. Like all cichlids, A. burtoni lives in a hierarchical social system where showy dominant males defend small territories that are used for courtship and breeding. However, dominance among male cichlids is reversible: If a subordinate successfully challenges a dominant male in a face-to-face confrontation, the dominant fish will lose his status and with it his vibrant coloring, black eyebar and the ability to produce sperm.
In earlier studies, Fernald a