Crested black macaque, Sulawesi crested macaque, Black ape, Yaki, Wolai
The Celebes crested macaque (Macaca nigra ), also known as the crested black macaque, Sulawesi crested macaque, or the black ape, is an Old World monkey that lives in the Tangkoko reserve in the northeastern tip of the Indonesian island of Sulawesi (Celebes), as well as on smaller neighboring islands.
The Celebes crested macaque is a large primate with distinctive kidney-shaped, bright pink ischial callosities. The tail is short, having the form of a nubbin. The body is black, covered with rough, thick, and wooly fur. The black face of the primate is coated with a dense layer of hair. Compared to other macaques, their skull is more projecting and baboon-like. Hairs on the top of their head compose a crest, facing up and backward. The coloration of young macaques is noticeably paler, closer to brown than black. They have black hairs on their crown, where further the crest appears. Older males can be identified by grizzled coats, especially in their upper body. Meanwhile, the same color can sometimes be found on the arms of younger males.
Currently, the species inhabits the island Pulau Bacan, Tangoko Reserve, and the northeastern part of Sulawesi island in Indonesia. On the island Sulawesi, the Celebes crested macaques are mainly found within protected areas, including Tangkoko Batuangus Nature Reserve, Gunung Ambang, the Gunung Lokon, the Bunaken Marine National Park as well as Gunung Manembo-nembo Nature Reserve. These primates live in humid environments, preferring habitats such as tropical lowland and upland rainforests as well as agricultural areas, which have occupied some parts of their natural range.
Celebes crested macaques are diurnal animals, socializing in the morning and resting in the afternoon. When awake, they spend about 59% of their time moving, foraging, and feeding. These terrestrial primates typically sleep in trees. The macaques travel 2.4 km a day on average. Meanwhile, those, living in primary forests, usually spend less time traveling due to the abundance of fruit they feed upon. The Celebes crested macaques are highly territorial animals, gathering into groups. Groups of this species are very large for their genus, containing 50-97 primates, the majority of which are females. Male macaques typically show submission and satisfaction by making a grimace or smacking their lips. Meanwhile, to express aggression, they yawn, chase, and stare with an open mouth as well as grin with their mouth closed.
These animals have a herbivorous primarily frugivorous diet. They feed upon fruits, especially figs, and will supplement their diet with 145 various plants and invertebrates. So when fruits are hard to find, the macaques can consume young leaves, shoots, and stems of flowering plants as well as insects.
Celebes crested macaques have polygynandrous (promiscuous) mating system, where both males and females mate with multiple mates. The macaques mate throughout the year with peak activity period among adult females, lasting from August to June. Females give birth with an interval of 18 months with gestation period of 5.5 months, yielding a single baby, usually between January and May. Reaching the age of 4 months, young macaques begin to spend less time with their mother, and are eventually weaned at 1 year old. Maturity is reached by the age of 3-4 years.
One of the major threats to the population of Celebes crested macaques is hunting: on the island Sulawesi, where these primates live, their meat is considered a delicacy, which brings to large-scale hunting of this species. Other notable threats include deforestation, the extension of human habitat, and the alteration of their natural range into agricultural areas.
According to IUCN Red List, the total population size of the Celebes crested macaques varies from 4,000 to 6,000 individuals throughout Sulawesi Island, and approximately 100,000 - on Pulau Bacan Island. Currently, this species is classified as Critically Endangered (CR) on the IUCN Red List and its numbers today are decreasing.
Due to feeding upon various fruits, Celebes crested macaques are important seed dispersers throughout their range, aiding some rainforest trees such as Ficus or Dracomelon.
