Pilot experiments to test group tolerance to a stranger in wild Macaca fascicularis

On the island of Peutjang, at the western tip of Java, three transplantation experiments with five individuals of Macaca fascicularis were carried out. In the first experiment, a subadult male was set free in the home range of the neighboring group. In the second experiment, an adult female was brought to the home range of a group separated from her own by several intervening groups. Both individuals found their own home ranges unharmed. In the third experiment, three individuals from an island 18 km away were transplanted to Peutjang. Thereafter, they were mostly found together, and they frequently associated with peripheral males of resident groups. During a month of observation they were not integrated into a resident group, but remained unharmed. The relationship of a group to its neighbors is considered as a fading‐out extension of the social network, rather than a territorial intolerance.