Crested monkey ( Macaca nigra )
|( Desmarest , 1822)|
The crested monkey or crested macaque ( Macaca nigra ) is a species of primate from the genus of macaques within the family of vervet monkeys (Cercopithecidae). Crested monkeys live in the northeast of the northern peninsula of the Indonesian island of Sulawesi (Celebes) as well as on the smaller neighboring islands of Manado Tua and Talise and on the Moluccan island of Bacan , where they were introduced by humans.
With the exception of a few white hairs in the shoulder area, their fur is jet black, as is their hairless face or face that is only covered by short hair. Young animals have a pink face. The normal swelling of the females is kidney-shaped and pink in color. The anus and scrotum are red. The long muzzle with the high cheek strips, especially in adult males, and the 5 to 15 cm long head of hair on the top of the head are striking. The tail is only a stub about 2 centimeters long. With a head body length of 45 to 57 centimeters and a weight of 5.5 to 8 (females) or 10 to 13 kilograms (males), they belong to the smaller macaque species. The crested monkey can be easily distinguished from the neighboring Gorontalo macaque ( Macaca nigrescens ) mainly by its darker color.
Way of life
Crested monkeys are diurnal rainforest inhabitants who prefer primary forests , but also seek out secondary forests , freshly felled forest areas, grassland or land cultivated by humans when primary forest to which they can retreat is nearby. They mainly stay in the trees for foraging and sleeping, but they often come to the ground where they spend about 60% of their time. They live in large groups of 60 to 80, occasionally with more than 100 animals. However, small groups of around 25 animals have also been observed. However, the females are always in the majority in an average ratio of 2.9: 1. The areas used by a group range from 74 to 350 hectares, depending on the size of the group and the time of year. In the rainy season they are bigger. Since young males have to leave their birth group after reaching sexual maturity, they sometimes form small all-male groups before joining an existing mixed group. Sometimes they switch between different groups several times. The repertoire of means of communication includes a number of sounds and facial expressions; the presentation of the long canines, for example, is a clear threatening gesture.
Compared to other macaques, crested monkeys are socially tolerant and very peaceful. They spend a quarter of their time in social activities, especially grooming each other . Conflicts between two animals are usually only carried out with low intensity and end in a mutual reconciliation. In contrast to many other ape species, a social interaction between females of different kinship groups can also be observed frequently. Males, on the other hand, can get involved in rank fights which also lead to injuries.
The crested monkey's diet consists of almost two thirds of fruits. Invertebrates, such as insects (e.g. caterpillars), make up almost a third of their diet. The rest of the diet consists of leaves, buds, bird eggs, and small vertebrates such as frogs, lizards, snakes, and bats. Occasionally plantations are visited to eat coconuts, mangoes, the fruits of the sugar palm or other agricultural products.
The readiness of the females to conceive is indicated by a clear swelling , in which the hairless anal region turns reddish, which is particularly noticeable with the black coat color. During copulation, the animals utter loud calls. The gestation period is around 175 days. Crested monkeys reproduce all year round, but three quarters of the young are born in the rainy season from December to June, when the food supply is greater. Young animals are suckled for around a year and become sexually mature at 3 to 4 years of age, females a little earlier than males. The average interval between two births is 22 months. The life expectancy of crested monkeys can only be estimated at around 20 years.
Crested monkeys are hunted on the one hand because they sometimes devastate plantations and fields, on the other hand because of their meat, which is considered a delicacy. The deforestation of the rainforests and ever increasing urban sprawl represent an additional problem. Since 1978 the population has decreased by 85%. The largest population lives today in the Tangkoko Duasaudara reserve . But crested monkeys only inhabit around 3600 ha of the reserve. Of all six macaque species in Sulawesi, the crested monkey is the most threatened. Their situation is somewhat better on the small neighboring islands of Sulawesi, as these are sparsely populated. On Bacan , where the population was estimated at 100,000 individuals in 1998, the crested monkey population is safer. However, it shows little genetic variability , as the founder population introduced by humans was only small. The IUCN , which only assesses the population on Sulawesi and the neighboring islands, classifies the crested monkey as critically endangered .
- Thomas Geissmann: Comparative Primatology . Springer, Berlin 2003, ISBN 3-540-43645-6 .
- Elizabeth L. Gadsby, Colin P. Groves, Aoife Healy, K. Praveen Karanth, Sanjay Molur, Tilo Nadler, Matthew C. Richardson, Erin P. Riley, Anthony B. Rylands, Lori K. Sheeran, Nelson Ting, Janette Wallis, Siân S. Waters & Danielle J. Whittaker: Family Cercopithecidae (Old World Monkeys). in Russell A. Mittermeier , Anthony B. Rylands & Don E. Wilson : Handbook of the Mammals of the World: - Volume 3. Primates. Lynx Editions, 2013 ISBN 978-8496553897 . Page 631.
- Macaca nigra in the IUCN 2017-1 Red List of Endangered Species . Posted by: J. Supriatna, N. Andayani, 2008. Retrieved August 1, 2017.
- Kristina A. Cawthon Lang: Primate Factsheets: Crested black macaque (Macaca nigra) . University of Wisconsin, February 2, 2006, accessed August 1, 2017.