Sleeping sites, sleeping trees, and sleep-related behaviors of black crested gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, central Yunnan, China

Data on sleep-related behaviors were collected for a group of central Yunnan black crested gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China from March 2005 to April 2006. Members of the group usually formed four sleeping units (adult male and juvenile, adult female with one semi-dependent black infant, adult female with one dependent yellow infant, and subadult male) spread over different sleeping trees. Individuals or units preferred specific areas to sleep; all sleeping sites were situated in primary forest, mostly (77%) between 2,200 and 2,400 m in elevation. They tended to sleep in the tallest and thickest trees with large crowns on steep slopes and near important food patches. Factors influencing sleeping site selection were (1) tree characteristics, (2) accessibility, and (3) easy escape. Few sleeping trees were used repeatedly by the same or other members of the group. The gibbons entered the sleeping trees on average 128 min before sunset and left the sleeping trees on average 33 min after sunrise. The lag between the first and last individual entering the trees was on average 17.8 min. We suggest that sleep-related behaviors are primarily adaptations to minimize the risk of being detected by predators. Sleeping trees may be chosen to make approach and attack difficult for the predator, and to provide an easy escape route in the dark. In response to cold temperatures in a higher habitat, gibbons usually sit and huddle together during the night, and in the cold season they tend to sleep on ferns and/or orchids.

Singing Behavior and Singing Functions of Black-Crested Gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, Central Yunnan, China

We used data on loud duetted and solo songs collected from one habituated polygynous group of black-crested gibbons (Nomascus concolor jingdongensis) on Mt. Wuliang, Yunnan, to test several hypotheses about the functions of these songs. The major function

The Critically Endangered black crested gibbon Nomascus concolor on Wuliang Mountain, Yunnan, China: the role of forest types in the species' conservation

The Critically Endangered black crested gibbon Nomascus concolor of China, Laos and Vietnam is threatened by deforestation and habitat destruction but there have been no studies of how it uses its forest habitat, probably because of the typically rugged t

Gibbons under seasonal stress: the diet of the black crested gibbon (Nomascus concolor) on Mt. Wuliang, Central Yunnan, China

The diet of a habituated group of black crested gibbon (Nomascus concolor jingdongensis) was studied from March 2005 to April 2006 in the Wuliang Mountains, central Yunnan, China. Gibbons consumed 77 different plant species, one mammal-, two bird-, one li

Predation on giant flying squirrels (Petaurista philippensis) by black crested gibbons (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China

Predation on vertebrates is infrequent in gibbons. In a 14-month field study of the central Yunnan black crested gibbon (Nomascus concolor jingdongensis) at Mt. Wuliang, Yunnan, China, we observed gibbons attacking, killing and eating giant flying squirre

Genetic diversity of the black crested gibbon (Nomascus concolor) from the Wuliang Mountains of Yunnan, China: preliminary results.

The authors thank Peng Shi, Scott Groom, and two anonymous reviewers for helpful comments. This work was supported by grants from the National Basic Research Program of China (973 Program, 2007CB411600), National Natural Science Foundation of China, and Bureau of Science and Technology of Yunnan Province (to Y.-P.Z.).

Maintenance of Multifemale Social Organization in a Group of Nomascus concolor at Wuliang Mountain, Yunnan, China

Many short-term studies have reported groups of black crested gibbons containing >= 2 adult females (Nomascus concolor). We report the stability of multifemale groups in this species over a period of 6 yr. Our focal group and 2 neighboring groups included 2 breeding females between March 2003 and June 2009. We also habituated 1 multifemale group to observers and present detailed information concerning their social relationships over a 9-mo observation period. We investigated interindividual distances and agonistic behavior among the 5 group members. The spatial relationship between the 3 adult members (1 male, 2 females) formed an equilateral triangle. A subadult male was peripheral to the focal group, while a juvenile male maintained a closer spatial relationship with the adult members. We observed little agonistic behavior among the adult members. The close spatial relationship and lack of high rates of agonistic behavior among females suggest that the benefits of living in a multifemale group were equal to or greater than the costs for both females, given their ecological and social circumstances. The focal group occupied a large home range that was likely to provide sufficient food sources for the 2 females and their offspring. Between March 2003 and June 2009, 1 adult female gave 2 births and the other one gave 1 birth. All individuals in the focal group survived to June 2009. A long-term comparative study focused on females living in multifemale groups and females living in pair-living groups would provide insight into understanding the evolutionary mechanisms of the social system in gibbons.

云南西南部地区黑长臂猿(Hylobates concolor)群构成、生态和行为的初步 研究

被观察的猿群各种群均生活于海拔2000—2700米的中山山地湿性常绿阔叶林 中, 以无量山数量最多, 约117—144群。猿群属小群体, 平均3.0±1.4只(N=12, 范围=2-5), 为一夫一妻制。日活动时间达576±30min, 其中鸣叫占3%; 游走 占14%; 取食占33%; 休息占50%; 日行程平均795±153米; 家域约44—49公顷, 平均每天利用7.4公顷。图4表3参18

ECOLOGY AND BEHAVIOR OF WILD BLACK-CRESTED GIBBONS (HYLOBATES-CONCOLOR) IN CHINA WITH A RECONSIDERATION OF EVIDENCE FOR POLYGYNY

The black-crested gibbon, Hylobates concolor, is one of the few species of gibbons that has not yet been the subject of a long term field study. Field observations in the Ai Lao and Wu Liang Mountains of Yunnan Province, China indicate that in this area the habitat and ecology of this species differ markedly from those of other gibbons that have been studied to date. These differences are correlated with some behavioral differences. In particular, these gibbons apparently have greater day ranges than other gibbons. It has also been suggested that this species lives in polygynous groups. To demonstrate this requires observation of groups with two or more females with young. Our own observations and those from other recent studies suggest that there are alternative explanations consistent with available data.

FEEDING AND VOCAL BEHAVIORS OF BLACK GIBBONS (HYLOBATES-CONCOLOR) IN YUNNAN - A PRELIMINARY-STUDY

Feeding and vocal behaviours of wild black gibbons (Hylobates concolor) were observed from 1987 to 1989 in south-western Yunnan, notably H. concolor jingdongensis at Mt. Wuliang (24-degrees 18-42'N, 100-degrees 30-50'E) in the early spring of 1989. 12 plant species were observed to have been eaten by the gibbons; these included tree species, lianas and epiphytes. Approximately 21 % of feeding time was devoted to eating fruits, 61 % to leaf buds and shoots, 7 % to flowers and 11 % to leaves. The gibbons preferred fruits to leaves even though they commonly ate leaves. In this study, the morning songs (duet and solo), reponsive (territorial) songs, alarm calls and communication calls were recorded. The gibbons sang their morning songs mainly in the early morning, with a single bout lasting more than 10 min on average. The singing of a group would trigger other groups, and all groups in an area tended to sing sequentially. The morning duet song bout was dominated by an adult male. The male emitted booms, aa notes, early multimodulated figures, intermediate multimodulated figures and codas, the latter occurring only in duets following the female's great call. The female uttered great calls and abortive great calls. The subadults or juveniles also took part in the morning songs. Lone males were heard to utter solos which lasted longer than the duets of the pairs.

西黑冠长臂猿（Nomascus concolor）栖息地与鸣叫特征分析

本研究重点对云南哀牢山、无量山、永德大雪山以及老挝 Nam Kan 保护区西黑冠 长臂猿(Nomascus concolor)的鸣叫特征进行了分析研究，以探讨长臂猿鸣叫个体特异性 的发生机制及其在地理种群区分或亚种地位划分中的意义；同时对哀牢山平河西黑冠长 臂猿栖息地乔木结构进行了样方调查，揭示西黑冠长臂猿高海拔栖息地的乔木结构特 征，为后续行为学研究提供基础生态数据。 研究表明，云南省哀牢山平河（N 24°20′09.5″, E 101°17′16.1″, 海拔2600m）的黑 长臂猿栖息地有乔木57 种隶属于23 科37 个属；木质藤本植物9 种隶属于6 科8 属。 优势科主要为杜鹃花科（Ericaceae）、木兰科（Magnoliaceae）、山茶科（Theaceae）和 壳斗科（Fagaceae）植物。乔木的多样性指数、均匀度指数在沟底明显降低，而乔木1 层和2 层所占的比例以及木质藤本的平均多度均随着坡位的下降而升高。与其他地区的 长臂猿相比，哀牢山黑长臂猿的活动高度较低（10—22m），果实性食物种类较少。 西黑冠长臂猿的雄性鸣叫包括Boom 音节、aa 音节、弱调节音节、强调节音节和 coda 音节，Boom 音节只是一单独的条带状音节，结构最简单也最稳定；aa 音节、弱调 节音节、强调节音节和coda 音节的稳定性则呈现出依次增大的趋势。强调节音节和coda 部分的稳定性在总体没有显著差异，但在某些变量上coda 音节比强调节音节有显著更 高的稳定性。在此基础上，重点基于对coda 音节的分析，发现同一地点不同群体的雄 性西黑冠长臂猿个体之间存在非常显著的鸣叫特异性，并且同一地点不同群体的雄性个 体之间鸣叫的差异，显著高于不同地点间雄性个体间鸣叫的差异。这一发现表明西黑冠 长臂猿很有可能在有意识地通过鸣叫声音的调节，来增加与邻近群体间鸣叫的差异性， 并依靠这一行为识别邻近群的成年个体和陌生个体或新成年的未配对个体，这对具领域 性、配对的长臂猿来说具有显著的生态适应意义。基于对西黑冠长臂猿所有4 个亚种雌 雄个体鸣叫的逐步判别分析，结果表明西黑冠长臂猿明显分为3 个类群：1) 指名亚种 （N. c. concolor）和景东亚种（N. c. jingdongensis）为同一类群；2)滇西亚种（N. c. furvogaster）类群；3)老挝亚种（N. c. lu）类群，综合我们及前人的研究结果，我们认 为老挝亚种与其它三个亚种之间很可能已经达到了亚种分化的水平，滇西亚种也是如 此，但其有效性还值得进一步研究和探讨，而指名亚种和景东亚种间可能还没有达到亚种分化的水平。