In many parts of Southeast Asia, the rainforest is being replaced by palm oil plantations. Due to the massive clearing of their habitat, some primates move to the plantations in search of food. This often leads to conflicts with farmers, even though the monkeys hardly harm them but, on the contrary, help to keep pests such as rats at low levels. The regular stay on the plantations, however, has a massive influence on the social behaviour of the macaques. This is shown in a new study by scientists from the Max Planck Institute for Evolutionary Anthropology (MPI-EVA), Leipzig University (UL), Universiti Sains Malaysia (USM) and the German Centre for Integrative Biodiversity Research (iDiv). Living in a manmade environment could have a negative effect on the development of the offspring and thus endanger the survival of the macaque populations in the long run. The new findings may help to develop appropriate measures for protecting the primate species, which is listed as vulnerable by the IUCN, and to promote peaceful coexistence between humans and wild animals.