Due to the deforestation of their habitats, macaques sometimes flock to palm oil monocultures to search for food. This sometimes leads to conflicts with farmers. However, macaques do not usually damage palm oil fruits excessively. In fact, they can even benefit crops, as they are excellent hunters of rats found in plantations (the main pest in monocultures).
However, as this study has been able to conclude, visiting plantations regularly has a significant impact on the social behavior of macaques. The research has been developed by scientists from the Max Planck Institute for Evolutionary Anthropology, the University of Leipzig, Sains University Malaysia and the German Center for Integrative Biodiversity Research.
Additionally, these new findings could help develop measures to protect primates.
Investigation Development
To carry out the research, the scientists spent several months observing two different groups of 50 southern pig-tailed macaques ( Macaca nemestrina ) in Segari, Malaysia. In this way, the researchers were able to observe that, every day, the groups walked for about three hours from the rainforest to the plantation.
In addition, the scientists wanted to find out the differences in the behavior of primates when they were in the rainforest and when they accessed the palm oil plantation. Although both groups had an abundance of food (in the form of fruits and rats) they were also more likely to conflict with humans.
However, the study focused on aggressive interactions, relationship-promoting behaviors (such as grooming or play), and social media within different groups (such as mother-child relationships).
Study results
As the researchers expected, the macaques used the plantation primarily as an additional food source, spending about two-thirds of their time foraging for and eating. The aggressive behavior of the macaques increased significantly inside the plantation (compared to other habitats), a phenomenon that usually occurs especially when they are looking for food.
However, according to scientists, the interior of the plantation (unlike the tropical forest) offers little protection against possible predators and puts the animals under stress, which is why the rates of aggression in primates increased.
