Macaca nigrescens
Creators: name: Russell A. Mittermeier
name: Anthony B. Rylands
name: Don E. Wilson
Publisher: name: Lynx Edicions
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Primates
Cercopithecidae
Macaca
Macaca nigrescens

description: 4.
Gorontalo Macaque
Macaca nigrescens
French: Macaque de Gorontalo / German: Gorontalo-Makak / Spanish: Macaco de Gorontalo
Other common names: Dumoga-bone Macaque, Temminck's Macaque
Taxonomy. Papio nigrescens Temminck, 1849,
Gorontalo, North Sulawesi Island, Indonesia.
In his 1969 review of the Sulawesi macaques,J. Fooden classified the distinct taxa as full species because he had no evidence of intergradation. In 1980, C. P. Groves reported on a zone of intergradation between M. nigra and M. nigrescens in the western tip of Bogani Nani Wartabone (Dumoga Bone) National Park in the downstream region of the Onggak Dumoga River, and he placed nigrescens as a subspecies of nigra. This classification was followed G. Corbet and J. Hill in their review The Mammals of the Indomalayan Region, published in 1992. The hybrid zone is restricted, however, and even though M. nigra and M. nigrescens are genetically quite similar and morphologically more similar to each other than to other species, they are distinct. Since 2001, Groves has classified M. nigraand M. nigrescens as separate species. Hybrids have been found with M. nigra and with M. heck: east of the Bolango River and near Bolaangitang. M. nigrescens is a member of the silenus species-group, including M. siberu, M. pagensis, M. leonina, M. nemestrina, M. silenus, and the other Sulawesi species. Monotypic.
Distribution. N Sulawesi, E of Gorontalo to Onggak Dumoga River in the N peninsula.
Descriptive notes. Head—body ¢.60 cm (males) and ¢.50 cm (females), tail c.2-5 cm; no specific data available for body weight. Pelage of young Gorontalo Macaquesis pale brown with blackish vertex, forearms, hands, and feet. It darkens with age into dark reddish-brown to blackish, with a black median streak on the lower back. As in the Crested Macaque (M. nigra), hairs of the vertex are elongated to an erectile crest. This crest is lacking in very young individuals, but grows with age. In adults, the crestis still slightly shorter (5-10 cm) than in the Crested Macaque. Ischial callosities are suboval to subreniform, dark orange to dark brown and without any internal subdivision.
Habitat. Lowland and montane rainforests up to elevations of 2000 m.
Food and Feeding. Gorontalo Macaques are more frugivorous than Crested Macaques, with fruits comprising 85% of their diet. Arthropods and vegetative plant parts are only a minor part of their daily intake (9% and 2:5%, respectively). They also raid cultivated crops (fruits, vegetables, and maize).
Breeding. Little is known about the reproductive biology of wild Gorontalo Macaques. A 14month study on semi-habituated wild individuals by A. K. Kohlhaas in 1989-1990 revealed that females breed throughout the year, but they give birth more often during the first half of the year, similar to neighboring Crested Macaques. As for all other Sulawesi macaques, females exhibit swellings of the anogenital region, but timing of maximum turgescence with ovulation remains unclear.
Activity patterns. Available data on sctivity patterns and strata use are derived from semi-habituated Gorontalo Macaques. They hardly come to the ground, spending more than 96% of their time in trees. Whether or not this figure is representative for the species or an artifact of human presence needs further investigation. It has also been reported that Gorontalo Macaques spend almost half of the daytime resting, followed by engaging in social activities (mainly grooming) and moving in almost equal parts (c.20% each). Only 10% oftheir daily activities consist of feeding. Increased fruit availability appears to lead to further reduction in feeding time on fruits. Similar to Crested Macaques, Gorontalo Macaques rest more during the dry season, particularly on hot days. Resting seems to center less on the midday but peaks more early and late in the day. Social activity is significantly influenced by fruit availability and temperature and, as such, decreases with increasing fruit availability and temperature.
Movements, Home range and Social organization. Gorontalo Macaques live in multimale—multifemale, female philopatric groups, which are believed to be smaller than those of Crested Macaques. Nevertheless, because no research has been conducted on totally habituated individuals, the reliability of group counts can be questioned. The only long-term study carried out on semi-habituated animals found a mean group size of 14 individuals, but up to 65 individuals were occasionally counted in a single group, with an adult male to adult female sex ratio of 1:1-7. Group sizes may have been underestimated because of group members being spread out in the dense forest. As in Crested Macaques, emigrating males often travel alone. Gorontalo Macaques are expected to be as socially tolerant as other, better studied, Sulawesi macaques, but evidence is still lacking. Agonistic behaviors appear to occur frequently, but with short duration. The severity and directionality of aggression and the frequency of reconciliation, however, remain unclear.
Status and Conservation. CITES Appendix II. Classified as Vulnerable on The IUCN Red List. The Gorontalo Macaqueis fully protected by Indonesian Law. Although the majority ofits distribution lies within a protected area, Bogani Nani Wartabone National Park, the population has declined in recent decades. The reason for the decline is conversion of accessible lowland rainforests, outside and in protected areas, into agricultural land and plantations. One of the affected areas is the former studysite of Kohlhaas, which has now been completely logged. There is also severe illegal hunting (market and subsistence) where macaques are not covered by a food taboo. The majority of Bogani Nani Wartabone National Park is inhabited by people of Muslim belief, and its center consists of massive, steep mountain ranges that are difficult to reach. In combination, this protects part of the population of Gorontalo Macaques relatively well. Whether Gorontalo Macaques still meet and hybridize with Heck’s Macaques (M. hecki) and Crested Macaques remains unclear but is doubtful at least for Heck’s Macaque.
Bibliography. Bynum et al. (1999), Corbet & Hill (1992), Fooden (1969), Groves (1980, 2001), Kohlhaas (1993), Kohlhaas & Southwick (1996), Lee, R.J. (1999, 2000), Lee, R.J. et al. (2005), Sugardjito et al. (1989), Thierry (2000b, 2007, 2011), Watanabe & Matsumura (1991).
description: Published as part of Russell A. Mittermeier, Anthony B. Rylands & Don E. Wilson, 2013, Cercopithecidae, pp. 550-755 in Handbook of the Mammals of the World – Volume 3 Primates, Barcelona :Lynx Edicions on pages 631-632, DOI: 10.5281/zenodo.6867065