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
Japanese macaque to 28 years and females up to 32 years. Japanese macaques live in matrilineal societies, and females stay in their natal groups for life, while males move out before they are sexually mature. Macaque groups tend to contain a number of adults of both sexes. In addition, a Japanese macaque troop contains several matrilines. These matrilines may exist in a dominance hierarchy with all members of a specific group ranking over members of a lower-ranking group. Temporary all-male groups also exist, composed of those that have recently left their natal groups and are about to transfer to another group. However,