Black crested gibbons, Nomasus concolor, are primarily found in Yunnan, China and have restricted ranges in western Laos and northern Vietnam (Geissmann and Orgeldinger 2000). Their distribution is discontinuous, with populations occurring between the Black and Red Rivers in southern China (Nomascus concolor concolor), near the China-Myanmar border (Nomascus concolor furvogaster), between the Mekong and and Chuanghe Rivers (Nomascus concolor jingdongensis), and in northwestern Laos (Nomascus concolor lu) (Groves 2001). (Geissmann and Orgeldinger, 2000; Groves, 2001)
Black crested gibbons live in evergreen, semi-evergreen, and deciduous forests in subtropical and mountainous areas (Geissmann and Orgeldinger 2000; Jiang et al. 2006). They are primarily observed at altitudes ranging from 2100 to 2400 m above sea level, where most of their food resources are concentrated (Fan and Jiang 2010). However, in Vietnam, black crested gibbons were observed living at altitudes from 1600 to 2000 m (Dao Van Tien 1985) and in Laos, from 550 to 900 m (Geissmann 2007). Black crested gibbons have been observed at altitudes as high as 2689 m (Fan and Jiang 2010). (Dao Van, 1985; Fan and Jiang, 2010; Geissmann and Orgeldinger, 2000; Geissmann, 2007; Jiang, et al., 2006)
Male black crested gibbons are black, while females are a tawny buff color. Females have a black crown and typically have black hair grizzling or covering the lower chest and abdomen (Mootnick and Fan 2011). This sexual dichromatism develops with age, as the female changes from black to buff or tawny coloration in early adulthood (Mootnick and Fan 2011). Black crested gibbons generally weigh from 6.9 to 10 kg (average 8 kg) and measure between 43 and 54 cm (average 50 cm) (Ma et al. 1988). (Ma, et al., 1988; Mootnick and Fan, 2011)
Black crested gibbons live in family units generally consisting of a monogamous male and female and their offspring. Although most black crested gibbons are monogamous, occasionally two females in a single breeding group are tolerated (Jiang et al. 1999). Polygyny has not been observed in other species of gibbons.
Singing may play a role in mate attraction, pair-bonding, and mate defense of black crested gibbons (Geissmann and Orgeldinger 2000; Fan et al. 2009). (Fan, et al., 2009; Geissmann and Orgeldinger, 2000; Jiang, et al., 1999)
Black crested gibbons reproduce once every 2 to 3 years, usually producing one offspring in each interval. The gestation period lasts about 7 to 8 months, and newborns weigh about 510 g at birth (Geissmann and Orgeldinger 1995). Offspring are weaned around 2 years of age, and they reach sexual maturity at about 8 years of age. (Geissmann and Orgeldinger, 1995)
Young black crested gibbons are nursed by their mother until about 2 years of age. Males and older offspring also provide care to young.
Black crested gibbons are believed to have similar longevity to other gibbons, which is estimated to be 25 to 30 years.
Black crested gibbons move using brachiation, which involves using their long arms to swing between tree branches. Though brachiation is their most common form of locomotion, they can also leap, walk, and climb (Haimoff et al. 1987).
Black crested gibbons live in family units generally consisting of a monogamous male and female and their offspring. Groups are territorial, but they retreat from human encroachment in their habitat, which has led to their limited present range (Jiang et al. 2006).
Black crested gibbons are diurnal and prefer to sleep in tall, thick trees with large crowns, located near food. Factors that tend to affect choice of sleeping trees are height, thickness, and crown size of the tree, the accessibility of the sleeping place, and the ease of escape. Individuals may or may not reuse sleeping trees, but individuals reusing a tree often sleep in the same place on the tree. Black crested gibbons sleep by wrapping their long arms around flexed knees and leaning their heads down (Fan and Jiang 2008b). (Fan and Jiang, 2008a; Haimoff, et al., 1987; Jiang, et al., 2006)
Black crested gibbons have a territory size averaging between 100 and 200 Ha (Jiang et al. 1999). However, one study noted that almost 70% of ranging occurred within 29 Ha (Fan and Jiang 2010). (Fan and Jiang, 2010; Jiang, et al., 1999)
Black crested gibbons communicate through vocalizations, including calls and songs, as well as physical interactions and facial expressions. The songs of black crested gibbons may be used for a variety of purposes, including defense of resources and establishment of territories (Sun et al. 2011), as well as attracting mates and strengthening pair bonds (Geissmann and Orgeldinger 2000). Black crested gibbons sing both alone and in pairs. Duets are usually initiated by males from high locations, such as tall trees on hills. Duets may play a part in mate attraction or pair-bonding between mates, defense of resources or mates, or group cohesion (Fan et al. 2009). (Fan, et al., 2009; Geissmann and Orgeldinger, 2000; Sun, et al., 2011)
In Yunnan, China, black crested gibbons are folivorous-frugivorous, spending on average similar amounts of time eating leaves and fruit. Their diet varies seasonally, based on the availability of food sources including leaves, fruits, buds, and flowers. In a study in 2008 (Fan et al.), black crested gibbons ate increased levels of figs in August and September, flowers in February and April, leaves in March, and buds and leaves in December and January. They prefer to eat fruits and figs over other foods during their first and last meals of the day (Fan et al. 2008). They have also been observed eating insects, eggs, and other small organisms. One population of black crested gibbons concentrated ranging behavior, staying in valleys with more abundant food for several consecutive days before moving to another, in order to avoid frequent passages through areas with little food (Fan and Jiang 2008). (Fan and Jiang, 2008b; Fan, et al., 2008)
Predation of black crested gibbons has not been well characterized.
Because they consume a considerable amount of fruit, black crested gibbons likely act as seed dispersers. They also act as hosts to a variety of nematodes, roundworms, and other parasites, including Dirofilaria digitata, Probstmayria gorillae, Streptopharagus pigmentatus, Streptopharagus sandgroundi, and Dipetalonema digitatum. (Yamashita, 1963)
Black crested gibbons can be found in some zoos worldwide. Although now restricted, hunting once contributed considerably to the decline of black crested gibbons.
There are no known adverse effects of black crested gibbons on humans.
Black crested gibbons are considered critically endangered by the IUCN (2010). Deforestation due to the steel industry, military activity during political unrest, and later to farming has greatly reduced viable habitat, threatening populations of black crested gibbons (Jiang et al. 2006). Although forests have been allowed to regenerate in some areas, in many others, farming has become permanent or invasive plant species have prevented forest regeneration (Jiang et al. 2006). Additionally, separation of small groups of this species due to habitat destruction may lead to decreased gene flow, further endangering the species (Jiang et al. 2006).
Hunting contributed to the extirpation of black crested gibbons in areas of Wuliang (Jiang et al. 2006). Although no reports of poaching have occurred since 1994, even low rates of hunting are projected to carry the risk of local extinction (Seal 1994). (Bleisch, et al., 2008; Jiang, et al., 2006; Seal, 1994)
Clarence Cheng (author), Yale University, Eric Sargis (editor), Yale University, Gail McCormick (editor), Special Projects.
uses sound to communicate
Referring to an animal that lives in trees; tree-climbing.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
parental care is carried out by females
an animal that mainly eats leaves.
an animal that mainly eats fruit
An animal that eats mainly plants or parts of plants.
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
found in the oriental region of the world. In other words, India and southeast Asia.
having more than one female as a mate at one time
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
uses sight to communicate
reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.
Bleisch, B., T. Geissmann, R. Timmins, J. Xuelong. 2008. "Nomascus concolor. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.4" (On-line). Accessed April 25, 2011 at http://www.iucnredlist.org/apps/redlist/details/39775/0.
Dao Van, T. 1985. Scientific results of some mammals surveys in North Vietnam (1957 - 1971). Ha Noi, Vietnam: Scientific and Technical Publishing House.
Fan, P., X. Jiang. 2010. Altitudinal ranging of black-crested gibbons at Mt. Wuliang, Yunnan: Effects of food distribution, temperature and human disturbance. Folia Primatologica, 81: 1-9.
Fan, P., X. Jiang. 2008. Effects of food and topography on ranging behavior of black crested gibbon (Nomascus concolor jingdongensis) in Wuliang Mountain, Yunnan, China. American Journal of Primatology, 70: 871-878.
Fan, P., X. Jiang. 2008. Sleeping Sites, Sleeping Trees, and Sleep-related Behaviors of Black Crested Gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, Central Yunnan, China. American Journal of Primatology, 70: 153-160.
Fan, P., Q. Ni, G. Sun, B. Huang, X. Jiang. 2008. Gibbons under seasonal stress: the diet of the black crested gibbon (Nomascus concolor) on Mt. Wuliang, Central Yunnan, China. Primates, 50: 37-44.
Fan, P., W. Xiao, S. Huo, X. Jiang. 2009. Singing behavior and singing functions of black-crested gibbons (Nomascus concolor jingdongensis) at Mr. Wuliang, Central Yunnan, China.. American Journal of Primatology, 71: 539-547.
Geissmann, T. 2007. First field data on the Laotian black crested gibbon (Nomascus concolor lu) of the Nam Kan area of Laos. Gibbons Journal, 3: 56-65.
Geissmann, T., N. Dang, N. Lormee, F. Momberg. 2000. Vietnam Primate Conservation Status Review 2000, Part 1: Gibbons. Hanoi: Fauna and Flora International, Indochina Programme.
Geissmann, T., M. Orgeldinger. 1995. Neonatal Weight in Gibbons (Hylobates spp.). American Journal of Primatology, 37: 179-189.
Geissmann, T., M. Orgeldinger. 2000. The relationship between duet songs and pair bonds in siamangs, Hylobates syndactylus.. Animal Behaviour, 60: 805-809.
Groves, C. 2001. Primate Taxonomy. Washington, DC, USA: Smithsonian Institute Press.
Haimoff, E., X. Yang, S. He, N. Chen. 1987. Preliminary Observations of Wild Black-crested Gibbons (Hylobates concolor concolor) in Yunnan Province, People's Republic of China. Primates, 28: 319-335.
Jiang, X., Z. Luo, S. Zhao, R. Li, C. Liu. 2006. Status and distribution pattern of black crested gibbon (Nomascus concolor jingdongensis) in Wuliang Mountains, Yunnan, China: implication for conservation. Primates, 47: 264-271.
Jiang, X., Y. Wang, Q. Wang. 1999. Coexistence of Monogamy and Polygyny in Black-crested gibbon (Hylobates concolor). Primates, 40: 607-611.
Ma, S., Y. Wang, F. Poirier. 1988. Taxonomy, distribution and status of gibbons (Hylobates) in Southern China and adjacent areas. Primates, 29: 277-286.
Mootnick, A., P. Fan. 2011. A Comparative Study of Crested Gibbons (Nomascus). American Journal of Primatology, 73: 135-154.
Seal, U. 1994. Thai gibbon life history and vortex analysis. Pp. 23-36 in S Tnhkorn, W Brockelman, R Tilson, U Nimmanheminda, P Ratanakorn, R Cook, A Teare, K Castle, U Seal, eds. Thai gibbon population and habitat viability analysis. Thailand: Khao Yai.
Sun, G., B. Huang, Z. Guan, T. Geissmann, X. Jian. 2011. Individuality in Male Songs of Wild Black Crested Gibbons (Nomascus concolor). American Journal of Primatology, 73: 431-438.
Yamashita, J. 1963. Ecological Relationships between Parasites and Primates. Primates, 4: 2-96.