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 he should mate. This is further supported by the fact that male ejaculation peaks at the same time that female sexual swelling peaks. There is not a sufficient change in female sexual behaviour around the time of ovulation in order to demonstrate to the male that the female is fertile. The swellings, therefore, appear necessary for predicting fertility. Barbary macaque females differ from other non-human primates in that they often mate with a majority of the males in their social group. While females are active in choosing sexual associations, the mating behaviour of macaque social groups is not entirely determined