Pagai Island macaque Pagai Island macaque The Pagai Island macaque ("Macaca pagensis"), also known as the Pagai macaque or Bokkoi, is an Old World monkey endemic to the Mentawai Islands off the west coast of Sumatra. It is listed as critically endangered on the IUCN Red List due to its ever-shrinking habitat. "Macaca pagensis" formerly included the overall darker Siberut macaque as a subspecies, but this arrangement is polyphyletic, leading to the two being classified as separate species. Both were formerly considered subspecies of the southern pig-tailed macaque. Pagai Island macaque males are generally larger than females. The males' body lengths range from
Barbary macaque males who have helped them in the past, this is not as important as relatedness in determining coalitions. Males avoid conflicting with higher ranking males and will more frequently form coalitions with the higher ranking male in a conflict. Close grouping of males occur when infant Barbary macaques are present. Interactions between males are commonly initiated when a male presents an infant macaque to an adult male who is not caring for an infant, or when an unattached male approaches males who are caring for infants. This behaviour leads to a type of social buffering, which reduces the number of