Pagai Island macaque a result, the water levels in the forest rivers fluctuate to a much greater degree than before. The alternating flooding and low water levels has also caused an increase in the population of malarial mosquitoes. 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
White-cheeked macaque "Macaca". In terms of outward appearance, it closely resembles the Assam macaque, which is one of the reasons the two were believed to be the same species until recently. The main differences between the two include the presence of white, elongated whiskers on the face of the white-cheeked macaque, which are absent from other species. The whiskers begin to grow as the creatures approach sexual maturity, and eventually cover the whole face, giving the animals a rounded facial appearance. The white-cheeked macaque also grows dense hair along its neck, while not growing any hair along its short tail. Additionally, there