A case report on ranging pattern of a solitary male macaque in urban area

Information on the life histories of male macaques after leaving their natal troops is limited. A solitary male Japanese macaque (Macaca fuscata), estimated to be 5 years old, appeared in the urban area of Ishinomaki City, Miyagi Prefecture, northern Japan, where no troops are distributed, in May 2023. Because the animal was habituated to and fed frequently on garden crops, it likely came from the western part of the prefecture, where multiple crop-feeding troops are distributed. The male stayed in the hilly area in the central part of the city until June and then moved north in July. The male moved south to the tip of the Oshika Peninsula and returned to the urban area in August, after which the location of the male was unknown. This study demonstrated that (1) male macaques can move > 40 km from their natal troop, (2) the daily travel distance (average: 0.9 km) of solitary males was similar to that of troop animals, whereas the home-range size of solitary males was much bigger than that for single animals, and (3) the home-range location of solitary males changes quickly. These results implied that solitary males in novel environments prioritize finding new troops to join. Our study sheds light on aspects of male life history after dispersal.