A study conducted in the Una Biological Reserve in the state of Bahia, Brazil, shows that in a habitat with high hunting pressure the risk of predation has such a significant impact on the behavior of the Yellow-breasted capuchin monkey Sapajus xanthosternos that it even avoids areas offering an abundant supply of plant biomass and invertebrates, its main sources of food.
An article reporting the findings of the study is published in the American Journal of Primatology.
"Many theories in the field of primatology assume that pressure to find food is more important that predation pressure. In this study we were able to show that predation pressure in Una counts for more in deciding where to be than where food is most abundant. These animals spend less time where food is plentiful because they perceive a higher risk of predation there. Another very important point is that this risk isn't posed only by natural predators but also by human predators—by poachers. Because of hunting pressure, they spend less time in places where the most food is available," said Patrícia Izar, last author of the article. Izar is a professor in the Department of Experimental Psychology at the University of São Paulo's Institute of Psychology (IP-USP).
The study was part of a research project by Priscila Suscke, first author of the article, for her Ph.D. in Una, which according to the researchers contains "a mosaic of habitats" including three predominant types of vegetation: Mature forest, secondary forest, and an agroforestry system known as cabruca, in which cacao trees introduced to replace the understory thrive in the shade of the native forest.
"It's not that food doesn't influence use of the area, but that in these different forest landscape environments in the Una Biological Reserve each environment contributes different amounts of food, and each poses a different level of risk [in terms of predation and poaching]," Suscke said."Our analysis of the factors influencing…