Gibbon Behavior Research Articles

Cardamom (Amomum tsaoko) agroforest is important habitat for skywalker hoolock gibbon (Hoolock tianxing) in Mt. Gaoligong, Yunnan, China

Understory plantation of cardamom (genus Amomum) is an ancient and widespread agroforestry practice in the eastern Himalayas and Southeast Asia, an area that supports high regional biodiversity. Cardamom provides an important cash income to rural people, and governments encourage cardamom cultivation as a replacement for slash-and-burn agriculture to alleviate poverty, aligning with the principles of the Globally Important Agricultural Heritage Systems (GIAHS) program initiated by the FAO. This program recognizes and supports traditional agricultural practices that contributes to biodiversity conservation and sustainable development. In this context, cardamom agroforestry not only supports local economies but also provides crucial habitat for animals, including the newly described skywalker hoolock gibbon (Hoolock tianxing). Nearly half of the remnant population of the skywalker hoolock gibbon lives in cardamom agroforest. In order to evaluate if gibbons could survive in cardamom agroforest for a relatively long term, we compared foraging behavior of gibbons over a year living in cardamom agroforests (group NA) and well-preserved forests (group BB) in Mt. Gaoligong, Yunnan, China. In response to habitat degradation caused by cardamom plantation, group NA increased feeding time and spent more time feeding on leaves. Notably, they consumed nuts of Castanopsis hystrix which is an unusual food type for gibbons. On the contrary, members of group BB rarely ate nuts though Castanopsis hystrix is abundant within its home range. However, group NA did not occupy a large home range, or travel longer in time or distance than group BB. We also monitored female reproduction of five groups for 5–13 years. Two adult females living in agroforests successfully reared two or three offspring with an inter-birth interval of five years. In addition, we surveyed group size of 16 groups (9 in agroforest vs. 7 in well preserved forests) from 2017 to 2023, and we found no significant difference in group size between habitats. Our results suggested that cardamom agroforest can sustain skywalker hoolock gibbons provided it is not too fragmented and hunting is prohibited.

Aktivitas Harian Siamang (Hylobates Syndactylus) Dalam Konservasi Ex-Situ Di Taman Margasatwa Dan Budaya Kinantan Bukittinggi Sumatera Barat

Gibbons is an endangered species. One of the efforts to prevent the extinction of the gibbons is the ex-situ’s conservation for example zoo. The purpose of this research to determine the daily behavior and the duration of activity of gibbons in habitat at ex-situ in Kinantan Zoo Bukittinggi and to know the difference of frequency daily activities of gibbons. The research was conducted in the month of October-December 2019. The object of this research are six gibbons. The research method was descriptive statistics. The type of this research is observation. Based on the research result, the daily behavior of gibbons at Kinantan Zoo Bukittinggi consists of: the behavior of moving, the behavior of voiced, the behavior of eating, the behavior of social, the behavior of rest, and other behavior (urinate). Total of activity time gibbons obtained during 30 days of observation is 18.319 minutes. The highest behavior shown in the behavior of the resting (12.920 minutes or 70,52% of total daily activity gibbons). The frequency of daily behavior with a long observation period of 10 hours until 10 hours 30 minutes every day.

Northern yellow-cheeked crested gibbons (Nomascus annamensis) travel and scan more at the cost of rest when in the presence of tourists

Abstract The tourism sector is a fast-growing contributor to the global economy, and nature-based tourism (NBT), particularly in Asia and Africa, is booming. Through the creation of jobs and revenue NBT has the potential to combat deforestation in regions that are economically poor, but of high biodiversity value. Inspired by the success of gorilla tourism in Uganda and Rwanda, several gibbon tourism projects have been initiated in Southeast Asia and China. Despite the existence of these programmes, no research has been done to investigate the impact of tourism on the behaviour of gibbons. To address this, we collected observational data on a group of northern yellow-cheeked crested gibbons (Nomascus annamensis) at Veun Sai-Siem Pang National Park (VSSPNP), Cambodia, in the presence and absence of tourists. We found there was a significant increase in the amount of time individuals spent scanning their environment and travelling at the cost of rest when in the presence of tourists. We also found that individuals were significantly more likely to self-groom in the presence of tourists. These results highlight the importance of scientific research in implementing successful, low-impact NBT programmes that consider animal behavioural changes. We are continuing to collect data on gibbons at VSSPNP and at Mt. Gaoligong National Nature Reserve, China with the aim of extending the IUCN’s best-practice guidelines for great-ape tourism to include the small apes.

My life among the apes.

I have spent over 40 years studying the behavior of our closest living relatives, the apes. In this paper, I review my research on the spacing, mating, and vocal behavior of gibbons and orangutans (Pongo pygmaeus) and the vocal and social behavior of chimpanzees (Pan troglodytes). I devote special attention to results derived from a 25-year-long study of a remarkable and extraordinarily large group of chimpanzees that has recently fissioned at Ngogo in Kibale National Park, Uganda. I conclude with some advice for the next generation of field primatologists.

Pre-release assessment of Javan Gibbon (Hylobates moloch) during acclimatization phase in Mount Malabar Protected Forest, West Java

Pre-release aassessment study of Javan gibbon (Hylobates moloch) in gradually during acclimatization phase in the Mount Malabar Protected Forest, West Java. We studied eleven Javan gibbons in February-March 2014, February-March 2015, March-April 2015, and July-August 2016. The purpose of this study was to assess the readiness of Javan gibbon behavior in acclimatization phase prior to release. Data collection was conducted by focal animal sampling method with 5-minute interval recording time and ad libitum method. The average time allocation of Javan gibbon activities were the following: feeding 16.82±1,28%; moving 20.01±3.14%; resting 47.64±1.31%; socializing 12.88±2.92%; sexual 0.69±0.54%; and vocalizing 1.96±0.59%. We compared activity allocation data from this study and those from wild Javan gibbons and found similarities as follows: 55.30% at a family of Jowo-Bombom-yani-Yudi, 51.42% at a pair of Moly-Nancy, 44.57% at a pair of Robin-Moni and 62.19% at a family of Mel-Pooh-Asri. Based on readiness assessment of 11 Javan gibbons, 3 were considered almost ready for release, while 8 individuals were considered ready.

Aktivitas dan Perilaku Pasangan Owa Jawa (Hylobates moloch) di Javan Gibbon Centre

Since 2008 Javan Gibbon’s ( Hylobates moloch ) status is endangered due to the capture of gibbons in the wild to be used as pets which are increasingly prevalent. Conservation efforts of Javan Gibbon population have been conducted at the rescue populations of Javan Gibbons in Javan Gibbon Centre (JGC). Javan Gibbon are the result of voluntary surrender of the community and confiscation of quarantine officer. Rehabilitation in JGC aims to restore the wild instincts of Javan Gibbon before being release d in to the wild environment . This study aimed to identify the daily activities and behavior patterns of Javan gibbon pair and to analyze the abiotic factors that influence them in Javan Gibbon Centre (JGC) as one aspect of the ir readiness to be release d into the wild environment . The study focused on three pairs of Javan Gibbons namely Boby-Jolly, Willie-Sasa , and Asep-Dompu. Based on the observation of three pair s of Javan gibbon, rest ing is the most dominant activity with the percentage of 60 - 80% followed by traveling (8 - 20%), feeding (7 - 13%), social (0 - 4%) , and aggressive behavior ( <1% ) . The most common social behavior s of Javan Gibbon pairs were allogrooming, courtship , and vocalization. Ambient temperature and rainfall were abiotics factors the most affecting the activity and behavior of the Javan Gibbon pair in terms of vocalization. Javan Gibbon will stop vocalization if the ambient temperature is low and when rainfall is high. Based on the observation data, Willie-Sasa was considered to have fulfilled one aspect of the assessment for the ir release into the wild environment . The dominant aspect of this pair is the frequency of socialization and vocalization that approaches frequency of Javan Gibbon behavior in the wild environment .

Pre-Release Assessment for Javan Gibbon (Hylobates moloch) in The Javan Gibbon Center, Mount Gede Pangrango National Park

Preparation for gibbons before being released into their habitat is crucial. Thus, there is a need for readiness assessment of Javan gibbon with several criteria derived from other species of gibbons to determine individual readiness. Pre-release assessment study for Javan gibbon (Hylobates moloch) had been conducted in January – February 2014, November – December 2014, and March-April 2016 in the Javan Gibbon Center, Mount Gede Pangrango National Park, West Java, Indonesia. The objective of this research was to assess the readiness of Javan gibbon behavior prior to release. Data collection was conducted by focal animal sampling method with 5-minute interval recording time and ad libitum method. The average time allocations of Javan Gibbon activities were as follow: feeding (18.17±3.34%); moving (22.34±0.53%); resting (46.24±3.84%); socializing (10.13±4.33%); sexual activity (0.59±0.58%); and vocalizing (2.54±0.88%). The similarities of activity allocation from this study compared by wild Javan gibbons data found as follows: feeding by 33.03%, moving by 90.97%, resting by 61.52%, socializing by 38.09%, vocalizing by 75.02%, and sexual by 44.24%. Based on readiness assessment of 11 Javan gibbons, 3 individuals were considered almost ready for release, while 8 individuals were considered ready. The assessment of behaviors criteria for the readiness of Javan gibbons before release has not existed before. The results of this research are important as a recommendation for the management of wildlife rehabilitation and as a guideline in implementing the rehabilitation and reintroduction program of Javan gibbons.

Kloss gibbon (Hylobates klossii) behavior facilitates the avoidance of human predation in the Peleonan forest, Siberut Island, Indonesia.

Kloss gibbons (Hylobates klossii) are endemic to the Mentawai Islands in Indonesia and have been subject to human predation for more than 2000 years in the absence of any other significant predators. We investigate the behavior of Kloss gibbons that may be attributed to avoiding human predation. We observed Kloss gibbons in the Peleonan forest in the north of Siberut Island, the northernmost of the Mentawai island chain, over 18 months in 2007 and 2008, and collected data on their singing behavior, the number of individuals present during different conditions and their responses to humans. We examine behaviors that may reduce the risk of predation by humans during singing (the most conspicuous gibbon behavior), daily non-singing activities and encounters with humans. The individual risk of being stalked by hunters is reduced by singing in same-sex choruses and the risk of successful capture by hunters during singing is reduced by singing less often during daylight hours and by leaving the location of male pre-dawn singing before full light (reducing the visual signal to hunters). Groups in the Peleonan also fission during non-singing daily activity and rarely engage in play or grooming, enhancing the crypticity of their monochromatic black pelage in the canopy. We also observed a coordinated response to the presence of humans, wherein one adult individual acted as a "decoy" by approaching and distracting human observers, while other group members fled silently in multiple directions. "Decoy" behavior occurred on 31% of 96 encounters with unhabituated Kloss gibbons that detected our presence. "Decoy" individuals may put themselves at risk to increase the survival of related immatures (and adult females with infants) who have a greater risk of predation. We argue that, in combination, these behaviors are an evolved response to a long history of predation by humans.

Locomotion behavior of cao vit gibbon (Nomascus nasutus) living in karst forest in Bangliang Nature Reserve, Guangxi, China

The cao vit gibbon is a critically endangered species. Only approximately 110 individuals remain in degraded karst forest along the China-Vietnam border. Karst forest is unusual gibbon habitat. Currently, the canopy height of cao vit gibbon habitat is approximately 10 m. Research on the locomotor behavior of gibbons living in this particular forest type might provide important insight into locomotor stability and variability of gibbons. We used 5 min scan samples to record the locomotion mode, support use and canopy strata of gibbons in 3 groups for 2096 h between January 2008 and December 2009. Although cao vit gibbon habitat has a lower canopy in comparison to that of other forests inhabited by gibbons, cao vit gibbons displayed a similar overall locomotor pattern to other gibbon species (Symphalangus syndactylus, Hylobates lar and Hylobates agilis) in which brachiation dominate their locomotor behavior. Cao vit gibbons spent most of their time travelling on inclined branches (2-10 cm) in the middle stratum through the forest canopy. Adult females appear to more often employ safer modes of locomotion (bridging more often and brachiation less), while adult males choose riskier modes (leaping more and climbing less). As gibbons increased in body weight, as they grew from infant to adult, they tended to use larger supports. This research documented that locomotor behavior in Hylobatidae is strongly determined by anatomical characters, but cao vit gibbons also show the ability to use various supports, enabling them to survive in karst forest.

Responses of Javan Gibbon (Hylobates moloch) Groups in Submontane Forest to Monthly Variation in Food Availability: Evidence for Variation on a Fine Spatial Scale

Primates tend to prefer specific plant foods, and primate home ranges may contain only a subset of food species present in an area. Thus, primate feeding strategies should be sensitive to the phenology of specific species encountered within the home range in addition to responding to larger scale phenomena such as seasonal changes in rainfall or temperature. We studied three groups of Javan gibbons (Hylobates moloch) in the Gunung Halimun-Salak National Park, Indonesia from April 2008 to March 2009 and used general linear mixed models (GLMM) and a model selection procedure to investigate the effects of variation in fruit and flower availability on gibbon behavior. Preferred foods were defined as foods that are overselected relative to their abundance, while important food species were those that comprised >5% of feeding time. All important species were also preferred. Season and measurements of flower and fruit availability affected fruit-feeding time, daily path lengths (DPL), and dietary breadth. Models that included the availability of preferred foods as independent variables generally showed better explanatory power than models that used overall fruit or flower availability. For one group, fruit and preferred fruit abundance had the strongest effects on diets and DPL in the models selected, while another group was more responsive to changes in flower availability. Temporal variation in plant part consumption was not correlated in neighboring groups. Our results suggest that fine-scale local factors are important determinants of gibbon foraging strategies.

Phylogenetic Separation in Limb Use in Captive Gibbons (Hylobatidae): A Comparison Across the Primate Order

Although there have been few studies of self-scratching in primates, some have reported distinct differences in whether hands or feet are used, and these variations seem to reflect the evolutionary history of the Order. Monkeys and prosimians use both hands and feet to self-scratch while African great apes use hands almost exclusively. Gibbons represent an evolutionary divergence between monkeys and great apes and incidental observations at the Gibbon Conservation Center pointed to a difference in self-scratching among the four extant gibbon genera (Hoolock, Nomascus, Symphalangus, and Hylobates). To validate and further explore these preliminary observations, we collected systematic data on self-scratching from 32 gibbons, including nine species and all four genera. To supplement gibbon data, we also collected self-scratching information from 18 great apes (four species), five prosimians (two species), 26 New World Monkeys (nine species) and 20 Old World Monkeys (seven species). All monkeys and some prosimians used both hands and feet to self-scratch, whereas one prosimian species used only feet. All African great apes used hands exclusively (orangutans were an exception displaying occasional foot-use). This appears to represent a fundamental difference between monkeys and great apes in limb use. Interestingly, there was a clear difference in self-scratching between the four gibbon genera. Hylobates and Symphalangus self-scratched only with hands (like all African great apes), while Hoolock and Nomascus self-scratched with both hands and feet (like monkeys and prosimians). This difference in gibbon behavior may reflect the evolutionary history of gibbons as Hoolock and Nomascus are thought to have evolved before both Hylobates and Symphalangus. What evolutionary pressures led to this divergent pattern is currently opaque; however, this shift in limb preference may result from niche separation across the order facilitating differences in the behavioral repertoire associated with hind and forelimbs.

Diet and ranging behavior of the endangered Javan gibbon (Hylobates moloch) in a submontane tropical rainforest

Altitude influences forest structure and food abundance and distribution, which in turn affect primate feeding and ranging patterns. Javan gibbons (Hylobates moloch) are endemic to forests spanning a broad range of altitudes on Java, Indonesia. Most information about Javan gibbon behavior comes from studies in lowland forests, while the vast majority of wild gibbons remaining inhabit hill and lower montane forests. We studied the diets, activity patterns, and ranging behavior of three gibbon groups in hill/lower montane (950-1,100 m asl) forest in the Gunung Halimun-Salak National Park (GHSNP) from April 2008 to March 2009. The mean home range size was 37 ha and the mean daily path length was 1,180 m. The study groups spent 36% of time feeding, 41% resting, 15% traveling, 6% engaging in social behavior, and 2% in aggressive interactions. Fruit was the most important food (63% of feeding time) followed by leaves (24%), and flowers (12%). Our results suggest that Javan gibbons in higher elevation habitats have substantially larger home ranges than lowland populations, despite broad similarity in their activity budgets and diets. Conservation managers should consider the effects of altitude and habitat quality on gibbon ranging behavior when developing habitat corridors, selecting sites for translocation or reintroduction projects, and designating and managing protected areas.

Biology and behaviour of reintroduced gibbons

We observed and recorded the behaviours of gibbons undergoing rehabilitation, before and after release, to document the behavioural and social changes of gibbons in the rehabilitation program and develop criteria for determining the suitability of a pair of gibbons for release. Hylobates albibarbis were observed at the Kalaweit Gibbon Rehabilitation Project in Kalimantan, Indonesia. Data were collected on animals both pre- and post-release and on wild gibbons for comparison. Data presented here show that reintroduced gibbons are capable of surviving without human intervention. In addition, their behaviour is similar to that of wild gibbons in terms of activity budgets, position in the canopy, body posture, pair association (PA) and diet. Prior to this study, no attempt has been made to quantify the rehabilitation process for gibbons, and rehabilitation project personnel require data reporting all aspects of a release so that improvements can be made. It is important to report these data for the benefit of future releases. Criteria, based on the behaviour of wild gibbons, are proposed to assist rehabilitation centers in assessing the suitability of gibbon pairs for release.

Effects of meteorology, astronomical variables, location and human disturbance on the singing apes: Hylobates albibarbis

Gibbons are characterized by their species-specific calls. The frequency of singing is known to be affected by rainfall, with singing occurring less in the wet season. I investigate the hypothesis that gibbon singing is also affected by the natural light-dark cycle, and by the changing light intensity and air quality resulting from the smoke haze which blankets the Indonesian island of Borneo on a yearly basis. I compare three singing variables-onset of singing, average duration of singing bout and number of female great calls produced during the dry season of 2006 when there was no smoke haze (June-August) and when there was smoke haze present (September-November). I present evidence which indicates that the changes in singing behavior are affected by changes in rainfall and smoke intensity but not by other meteorological factors (i.e. wind and light intensity) or changing astronomical cues (light intensity, month, time of sunrise, time of moonrise, nocturnal illumination index, day length and night length). The possible long-term effects of this on gibbon behavior and territoriality are discussed. The need to carry out more research on the long-term effects of the smoke haze on wildlife behavior and possible solutions to the problem are discussed.

Primatology. Homeland defense in the wild.

PRIMATOLOGYINUYAMA, JAPAN-- The 100 participants in Research on Long-Lived Animals held here 15 to 18 January discussed the driving force behind male territoriality in chimpanzees, the behavior of gibbons toward long-lost relatives in need, and a successful effort to protect muriquis in Brazil. But they also explored the sociability of primates, with both welcoming and farewell parties and a trip to a traditional Japanese pub.

Longitudinal study of delayed reproductive success in a pair of white‐cheeked gibbons (Hylobates leucogenys)

AbstractConcern over a lack of breeding success in a pair of white‐cheeked gibbons (Hylobates leucogenys) prompted a four‐part study of gibbon behavior and physiology at the Lincoln Park Zoo. Data were collected to determine the female intermenstrual interval (IMI) and identify periods of peak receptivity. Subsequent behavioral data were gathered during both female menses and estrous periods to formulate a behavioral profile for each gibbon. The female experienced a species‐typical IMI of 21.6 days and exhibited heightened levels of behavioral receptivity toward the male during estrus. The male exhibited high levels of human‐directed behavior throughout the day. Closing the exhibit to visitors did not result in higher levels of social proximity or prosocial behavior between the pair, although it did eliminate the male's human‐directed behavior during the experimental condition only. The female exhibited higher levels of social grooming, solicitation of the male, and proximity to the male when the pair was locked indoors. Based on those findings, the pair was moved to an exclusively indoor exhibit. The female's visibility to the public decreased substantially in the alternate exhibit, but there were no other significant behavioral changes. Nearly one year after the exhibit change, the female gibbon was confirmed to be pregnant. Although the results of this study cannot be used to infer causal conditions that resulted in the pregnancy, they do support the notion that systematic documentation of animal behavior and physiology may be used as a tool for monitoring reproductive behavior and informing management decisions. Zoo Biol 21:413–434, 2002. © 2002 Wiley‐Liss, Inc.

Observations on the behavior of gibbons (Hylobates leucogenys, H. gabriellae, and H. lar) in the presence of mirrors.

Observations on the behavior of gibbons (Hylobates leucogenys, H. gabriellae, and H. lar) in the presence of mirrors.

Observations on the behavior of gibbons (Hylobates leucogenys, H. gabriellae, and H. lar) in the presence of mirrors.

Three captive gibbons (Hylobates leucogenys, H. gabriellae, and H. lar) were videotaped in the course of longitudinal exposure to mirrors introduced into their familiar cage or island housing situation. The gibbons, which differed in age, sex, species, and rearing condition, exhibited great individual differences in their behavioral reactions to mirrors, spanning from a minimal reaction dominated by social responses to a dramatic sequence of progressive behavioral change that featured a variety of contingency testing behaviors and included mirror-mediated, self-directed behavior. Additional information on the mirror competence of gibbons was provided by modified mark tests and a hidden object task. The results are discussed in relation to current criteria for self-recognition in primates and factors involved in individual and species differences in reactions to mirror exposure.

Hylobatid communities: Changing views on pair bonding and social organization in hominoids.

Social organization involving pair bonding and two-adult groups is rare in mammals. Current sociobiological theory suggests that this grouping and behavior pattern is somewhat anomalous. The gibbons (genus Hylobates) are the only hominoids to exhibit pair bonds and two-adult groups. In this article I present an overview of the current issues in monogamy and pair-bond theory, and review traditional conceptualizations and the accumulated data relevant to gibbon social organization. The significance of hominoid behavioral phylogeny and population-wide studies is also considered. Recent findings indicate that pair-bonding and two-adult groups are not ubiquitous among the hylobatids. Many aspects of gibbon behavior and ecology do not conform to expectations of the conditions under which two-adult groups and/or pair-bonding patterns should evolve. A review of the information available from long-term and short-term studies of gibbons suggests an alternative way of viewing their socioecology. I propose that gibbons currently exist in variable communities that have arisen via ecological pressures and specific behavioral patterns from an ancestral multimale/multi-female grouping pattern. This social organization is not best characterized as "monogamous." This review also suggests that hominoid grouping patterns can be viewed as occurring along a continuum rather than as being discretely different units.

A point-mass model of gibbon locomotion

In brachiation, an animal uses alternating bimanual support to move beneath an overhead support. Past brachiation models have been based on the oscillations of a simple pendulum over half of a full cycle of oscillation. These models have been unsatisfying because the natural behavior of gibbons and siamangs appears to be far less restricted than so predicted. Cursorial mammals use an inverted pendulum-like energy exchange in walking, but switch to a spring-based energy exchange in running as velocity increases. Brachiating apes do not possess the anatomical springs characteristic of the limbs of terrestrial runners and do not appear to be using a spring-based gait. How do these animals move so easily within the branches of the forest canopy? Are there fundamental mechanical factors responsible for the transition from a continuous-contact gait where at least one hand is on a hand hold at a time, to a ricochetal gait where the animal vaults between hand holds? We present a simple model of ricochetal locomotion based on a combination of parabolic free flight and simple circular pendulum motion of a single point mass on a massless arm. In this simple brachiation model, energy losses due to inelastic collisions of the animal with the support are avoided, either because the collisions occur at zero velocity (continuous-contact brachiation) or by a smooth matching of the circular and parabolic trajectories at the point of contact (ricochetal brachiation). This model predicts that brachiation is possible over a large range of speeds, handhold spacings and gait frequencies with (theoretically) no mechanical energy cost. We then add the further assumption that a brachiator minimizes either its total energy or, equivalently, its peak arm tension, or a peak tension-related measure of muscle contraction metabolic cost. However, near the optimum the model is still rather unrestrictive. We present some comparisons with gibbon brachiation showing that the simple dynamic model presented has predictive value. However, natural gibbon motion is even smoother than the smoothest motions predicted by this primitive model.