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Ulrich H Reichard - One of the best experts on this subject based on the ideXlab platform.
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short dispersal distance of males in a wild white handed gibbon Hylobates Lar population
American Journal of Physical Anthropology, 2018Co-Authors: Kazunari Matsudaira, Suchinda Malaivijitnond, Takafumi Ishida, Ulrich H ReichardAbstract:OBJECTIVES It has long been recognized that in gibbons both sexes disperse from the natal group. However, the fate of dispersed individuals was rarely documented. Here we provide the first detailed information on sex differences in dispersal patterns by analyzing the spatial genetic structure of a well-known white-handed gibbon (Hylobates Lar) population. MATERIALS AND METHODS Mitochondrial DNA (mtDNA) and Y-chromosomal haplotypes, and autosomal microsatellite genotypes were determined for individuals of the Mo Singto study site, Khao Yai National Park, Thailand. Mantel tests for the three genetic marker types were performed for 17 gibbon groups comprising 23 adult males and 18 adult females. RESULTS Significant positive Mantel correlations were observed for spatial distance and both autosomal microsatellite-based as well as Y-chromosomal haplotype-based genetic distance among adult males. Neighboring adult males tended to be genetically related and share Y-chromosomal haplotypes. Conversely, no significant Mantel correlations were observed either in autosomal microsatellites or mtDNA among adult females. DISCUSSION Our results confirm, at a genetic level, hypotheses from long-term demographic observations that white-handed gibbon males of the Mo Singto population primarily disperse into adjacent groups. Instead, females disperse more opportunistically either to adjacent or more distant groups. This sex-specific difference reflects an apparent greater tolerance between males than between females. The higher tolerance of adult males allows the formation of stable multimale groups and facilitates male dispersal into an adjacent group. Stable multifemale groups have never been documented for white-handed gibbons probably due to feeding competition between females.
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Short dispersal distance of males in a wild white‐handed gibbon (Hylobates Lar) population
American journal of physical anthropology, 2018Co-Authors: Kazunari Matsudaira, Suchinda Malaivijitnond, Takafumi Ishida, Ulrich H ReichardAbstract:OBJECTIVES It has long been recognized that in gibbons both sexes disperse from the natal group. However, the fate of dispersed individuals was rarely documented. Here we provide the first detailed information on sex differences in dispersal patterns by analyzing the spatial genetic structure of a well-known white-handed gibbon (Hylobates Lar) population. MATERIALS AND METHODS Mitochondrial DNA (mtDNA) and Y-chromosomal haplotypes, and autosomal microsatellite genotypes were determined for individuals of the Mo Singto study site, Khao Yai National Park, Thailand. Mantel tests for the three genetic marker types were performed for 17 gibbon groups comprising 23 adult males and 18 adult females. RESULTS Significant positive Mantel correlations were observed for spatial distance and both autosomal microsatellite-based as well as Y-chromosomal haplotype-based genetic distance among adult males. Neighboring adult males tended to be genetically related and share Y-chromosomal haplotypes. Conversely, no significant Mantel correlations were observed either in autosomal microsatellites or mtDNA among adult females. DISCUSSION Our results confirm, at a genetic level, hypotheses from long-term demographic observations that white-handed gibbon males of the Mo Singto population primarily disperse into adjacent groups. Instead, females disperse more opportunistically either to adjacent or more distant groups. This sex-specific difference reflects an apparent greater tolerance between males than between females. The higher tolerance of adult males allows the formation of stable multimale groups and facilitates male dispersal into an adjacent group. Stable multifemale groups have never been documented for white-handed gibbons probably due to feeding competition between females.
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RESEARCH ARTICLE Open Access
2016Co-Authors: Esther Clarke, Ulrich H Reichard, Klaus ZuberbühlerAbstract:Context-specific close-range “hoo ” calls in wild gibbons (Hylobates Lar) Esther CLarke1,2*, Ulrich H Reichard3 and Klaus Zuberbühler2,4 Background: Close range calls are produced by many animals during intra-specific interactions, such as during home range defence, playing, begging for food, and directing others. In this study, we investigated the most common close range vocalisation of Lar gibbons (Hylobates Lar), the ‘hoo ’ call. Gibbons and siamangs (family Hylobatidae) are known for their conspicuous and elaborate songs, while quieter, close range vocalisations have received almost no empirical attention, perhaps due to the difficult observation conditions in their natural forest habitats. Results: We found that ‘hoo ’ calls were emitted by both sexes in a variety of contexts, including feeding, separation from group members, encountering predators, interacting with neighbours, or as part of duet songs by the mated pair. Acoustic analyses revealed that ‘hoo ’ calls varied in a number of spectral parameters as a function of the different contexts. Males ’ and females ’ ‘hoo ’ calls showed simiLar variation in these context-specific parameter differences, although there were also consistent sex differences in frequency across contexts. Conclusions: Our study provides evidence that Lar gibbons are able to generate significant, context-dependen
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The Torso-Orthograde Positional Behavior of Wild White-Handed Gibbons (Hylobates Lar)
Developments in Primatology: Progress and Prospects, 2016Co-Authors: Matthew G. Nowak, Ulrich H ReichardAbstract:Torso-orthograde (TO)-positional behavior is a unifying characteristic of extant hominoids. Previous studies have highlighted the unique use of forelimb-suspensory dominated locomotion and posture among hylobatids, a tremendously successful radiation of small hominoid primates, often neglecting the importance of other TO-positional behaviors, causing hylobatid locomotion and posture to appear more stereotypic and less versatile, relative to the closely related Large-bodied nonhuman hominids (great apes). However, early and recent studies of hylobatid positional behavior have lacked the categorical detail necessary to effectively analyze and compare their TO-diversity and contextual use of TO-positional behaviors to those of other primates and in particuLar the Large-bodied nonhuman hominids. To address the deficit of knowledge of the complete positional repertoire of hylobatids, we observed in detail the positional behavior of a Large sample of adult white-handed gibbons (Hylobates Lar) at Khao Yai National Park, Thailand. We evaluated the TO-positional repertoire of 24 adult gibbons (11 females and 13 males), and the contextual use of their TO-positional repertoire. Our results indicate that Lar gibbons possess and use a diverse TO-positional repertoire that is comparable to that of Large-bodied hominids. A collective and flexible use of TO-locomotion and -posture allows Lar gibbons to maximize their exploitation of the arboreal canopy. We argue that hylobatids unique suspensory locomotion and posture coupled with a previously undocumented TO-versatility more accurately reflect the pattern of positional behaviors responsible for the small apes’ successful radiation and subsequent diversification across all of South and Southeast Asia’s forest habitats.
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Lar gibbon Hylobates Lar great call reveals individual caller identity
American Journal of Primatology, 2015Co-Authors: Thomas A Terleph, Suchinda Malaivijitnond, Ulrich H ReichardAbstract:Gibbons (family Hylobatidae) produce loud, elaborate vocalizations (songs), often in well-coordinated male/female duets. The female's great call, the most conspicuous phrase of the gibbon vocal repertoire, functions primarily to mediate territorial defense. Despite the fact that Lar gibbons (Hylobates Lar) are the most widely distributed and well researched hylobatid species and produce a rich vocal repertoire, the individual-specificity of their great calls has not previously been quantified. In addition, spectral and temporal features of notes occurring at specific locations within the Lar great call have not been described. Here we provide such a description, and test the hypothesis that great calls are statistically discriminable between a Large sample of individual callers. We compared recordings of great calls from 14 wild Lar females in Khao Yai National Park, Thailand. Our analyses of principal components derived from spectral and temporal measures, as well as spectrograms from the entire great call, indicate that acoustic variation is sufficient to allow identification of individual callers (83.5% discriminability based on principal components, and inter-individual call variation exceeding intra-individual variation in overall spectrogram). These vocalizations potentially allow individual recognition of animals.
Warren Y. Brockelman - One of the best experts on this subject based on the ideXlab platform.
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high interannual variation in the diet of a tropical forest frugivore Hylobates Lar
Biotropica, 2018Co-Authors: Udomlux Suwanvecho, Warren Y. Brockelman, Anuttara Nathalang, Jantima Santon, Umaporn Matmoon, Rathasart Somnuk, Narong MahannopAbstract:Frugivores must deal with seasonal changes in fruit availability and changes from year to year, as most species of tropical forest fruiting trees have considerable interannual variation in phenology and many are mast fruiters. We quantified seasonal and interannual changes in the fruit diet in a frugivore and important seed disperser, the white-handed gibbon, Hylobates Lar, in Thailand. We used 40-d following data during April and May replicated in six consecutive years to study interannual variability in the diet and compared it with seasonal changes measured in monthly samples of the same size collected in three successive years. The 40-d periods of following also allowed us to measure the decline in dietary simiLarity with time over a finer scale. We measured fruit diet simiLarity between replicated 5-d periods using the percentage overlap (Renkonen's) index and Jaccard's simiLarity index. Seasonally, average dietary overlap between adjacent months was low, and simiLarity approached zero after four months. Average rate of decline in simiLarity exceeded 20 percent per 5-d period. Variation in fruit species in the diet between years was high and was correlated with interannual variation in fruiting phenology. The strongest correlation occurred in the case of Nephelium melliferum, a highly preferred species that dominated the diet in good fruiting years. It is difficult to separate changes in food species preference from changes in availability from year to year. We devised a relative measure of preference that depends on the degree to which the gibbons rely on prior knowledge to find sources.
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Long-term home range use in white-handed gibbons (Hylobates Lar) in Khao Yai National Park, Thailand.
American journal of primatology, 2015Co-Authors: Thad Q. Bartlett, Lydia E. O. Light, Warren Y. BrockelmanAbstract:Ranging behavior is an important element of how nonhuman primates obtain sufficient resources to ensure biological maintenance and reproductive success. As most primates live in permanent social groups, group members must balance the benefits of group living with the costs of intragroup competition for resources. One way to mitigate the cost of intragroup feeding competition is to increase foraging-related travel, thereby increasing the number of patches visited. As a result we might expect home range size to increase as a function of group size. On the other hand, for perennially territorial species, ranging behavior may be constrained by the ranging requirements of territorial defense or by the location of neighboring territories, which would result in long-term stability in the size and location of a group's home range. In this study, we examined changes in range-use characteristics in one well-habituated group of white-handed gibbons (Hylobates Lar) during three study periods over a 10-year span. Group size changed from five members, two adults, two juveniles, and one infant, in 1994, to two adults in 2002, and to three adults and one sub-adult in 2004. Despite inter-annual changes in core area use we found that home range location was highly stable across years. Nevertheless, home range size was Larger and daily path length significantly longer in 2002 relative to 1994 when a dependent infant was present in the group. The percentage of time adults spent resting was also significantly greater in 1994 when the infant was present. These findings highlight the importance of considering group composition, in addition to group size, when evaluating the determinants of ranging behavior. We also consider the influence of individual and shared knowledge on home range stability.
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Gibbon (Hylobates Lar) reintroduction success in Phuket, Thailand, and its conservation benefits
American journal of primatology, 2015Co-Authors: Petra Osterberg, Phamon Samphanthamit, Owart Maprang, Suwit Punnadee, Warren Y. BrockelmanAbstract:We summarize the results from a long-term gibbon reintroduction project in Phuket, Thailand, and evaluate its benefits to conservation. Between October 2002 and November 2012, eight breeding families of white-handed gibbons (Hylobates Lar) were returned to the wild in Khao Phra Thaew non-hunting area (KPT). Wild gibbons were extirpated from Phuket Island by the early 1980s, but the illegal wildlife trade has continued to bring young gibbons from elsewhere to the island's popuLar tourist areas as pets and photo props. The Gibbon Rehabilitation Project (GRP) has rescued and rehabilitated confiscated and donated captive gibbons since 1992 and aims to repopulate the island's last sizable forest area. Following unsuccessful early attempts at translocation in the 1990s, GRP has now developed specific methods for gibbon reintroduction that have led to the establishment of a small independent, reproducing population of captive-raised and wild-born gibbons on Phuket. Eleven infants have been born wild within the reintroduced population, including a second generation wild-born gibbon in September 2012. Benefits of the GRP project include restoration of the gibbon population on Phuket, rescue of illegally kept gibbons, public education, training of personnel in gibbon conservation work, and gaining experience which may prove useful in saving more severely threatened species. It is unlikely that gibbon (and other Large primate) translocations will make a significant contribution to conservation of the species as a whole, and primate translocation projects should not be judged solely by this criterion.
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Population Dynamics of a Reintroduced Population of Captive-Raised Gibbons (Hylobates Lar) on Phuket, Thailand
Primate Conservation, 2014Co-Authors: Petra Osterberg, Phamon Samphanthamit, Owart Maprang, Suwit Punnadee, Warren Y. BrockelmanAbstract:Confiscated and donated white-handed gibbons ( Hylobates Lar) originating from the local wildlife trade have been rescued by the Gibbon Rehabilitation Project (GRP) and rehabilitated on Phuket since 1992. Here we present some results of this long-term gibbon reintroduction project. Following unsuccessful early release attempts beginning in 1993, GRP has experi- mented with reintroduction methods and developed a protocol that has succeeded in re-establishing a small independent breeding population in a 22-km 2 forest fragment on Phuket. Eight breeding families of gibbons were released into the Khao Phra Thaew non-hunting area between October 2002 and November 2012 using a soft-release reintroduction method in which the gibbons were provisioned with fresh food in the trees for at least one year, or as long as they needed it. The adult pair in the first gibbon family that was reintroduced there has remained together for 10 years post-release, they have maintained the original pair-bond and raised three wild-born offspring. The reintroduced population has seen eleven infants born in the wild, including a second- generation gibbon born to the first wild-born female. Female interbirth intervals and ages at first reproduction in the reintroduced population are comparable with those in wild populations. Of the seven adult females originally released, two remain with their original mates and two remain in the wild paired with different mates. By the end of 2012, three of the six wild groups were not nuclear families, indicating a flexibility of group composition seen in well-studied wild populations.
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white handed gibbon Hylobates Lar core area use over a short time scale
Biotropica, 2014Co-Authors: Norberto Asensio, Warren Y. Brockelman, Suchinda Malaivijitnond, Ulrich H ReichardAbstract:Core areas represent small regions within animal home-ranges intensively used during a given period of time. We assessed the quality of core areas relative to the rest of the home-ranges (i.e., non-core areas) of 11 groups of the territorial and highly frugivorous white-handed gibbon (Hylobates Lar) over a short-time scale to reflect temporarily available resources. Weekly core areas included consistently higher densities of the gibbons' important foods compared to non-core areas. Gibbon core areas partially overlapped at 46 percent with a model comprising the best hypothetical core areas based on a concentration map of available food sources. In addition, a maximization ratio estimated by dividing the cumulative dbh covered by gibbon core areas and the model reached an intermediate value. Gibbon core areas only partially mirrored food distribution probably because they represent a trade-off between covering regions with important food locations and areas needed for other biologically relevant activities such as territory defense. Results do not support the concept that core areas can represent the minimum area requirement that would allow a gibbon group to survive and reproduce successfully irrespective of the time period considered, which indicates that core areas alone should not be treated as a conservation target.
H. P. Brandt - One of the best experts on this subject based on the ideXlab platform.
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Über eine Microsporum–Enzootie bei Kappen–Gibbons (Hylobates Lar) verursacht durch eine Variante von Microsporum canis
Mycoses, 2009Co-Authors: H. P. R. Seeliger, W. Bisping, H. P. BrandtAbstract:Zusamenfassung Bericht uber die klinischen Symptome, den Verlauf und die Behandlung einer Mikrosporie–Enzootie bei 8 aus Siam importierten Kappen–Gibbons. Die aus Hautschuppen und Haaren der Tiere sowie aus Mortel und Einstreu der Kafige isolierten Mikrosporie–Erreger wiesen Eigenschaften von M. audouinii und M. canis auf. Aufgrund neuerer Befunde werden sie als ein Intermediartyp zwischen diesen beiden Arten angesehen, der den dysgonen M. canis–Stammen bzw. der M. canis–obesum–Variante weitgehend ahnelt und deshalb als zum Formenkreis von M. canis gehorend anzusehen ist. Die nur sparliche Entwick–lung auf Reiskornern kann nicht mehr als ein sicheres Merkmal zur Trennung des M. audouinii von anderen Mikrosporie–Erregern angesehen werden. Die Enzootic wurde durch Griseofulvin–Behandlung und laufende Desinfektion be–herrscht. Summary This report deals with the clinical symptoms, the course and the treatment of an enzootic among gibbon monkeys (Hylobates Lar) imported from Siam. The enzootic was caused by a Microsporum species. The causative agent was isolated from the scales and epilated hairs of the animals as well as from the straw and the walls of the cages. The properties of the cultured fungus resembled in some respects those of M. audouinii, in others those of M. canis. According to recent findings the isolated species is considered to have an intermediary position between M. audouinii and M. canis. As it resembles closely dysgonic strains of M. canis and the variety M. canis–obesum, respectively, it should be considered as belonging to the M. canis–group. Poor growth on rice grains can no longer be regarded as a safe diagnostic procedure for separating M. audouinii from other agents of Microsporum infections. The enzootic was controlled by griseofulvin treatment and by current desinfection of the cages.
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uber eine microsporum enzootie bei kappen gibbons Hylobates Lar verursacht durch eine variante von microsporum canis
Mycoses, 2009Co-Authors: H. P. R. Seeliger, W. Bisping, H. P. BrandtAbstract:Zusamenfassung Bericht uber die klinischen Symptome, den Verlauf und die Behandlung einer Mikrosporie–Enzootie bei 8 aus Siam importierten Kappen–Gibbons. Die aus Hautschuppen und Haaren der Tiere sowie aus Mortel und Einstreu der Kafige isolierten Mikrosporie–Erreger wiesen Eigenschaften von M. audouinii und M. canis auf. Aufgrund neuerer Befunde werden sie als ein Intermediartyp zwischen diesen beiden Arten angesehen, der den dysgonen M. canis–Stammen bzw. der M. canis–obesum–Variante weitgehend ahnelt und deshalb als zum Formenkreis von M. canis gehorend anzusehen ist. Die nur sparliche Entwick–lung auf Reiskornern kann nicht mehr als ein sicheres Merkmal zur Trennung des M. audouinii von anderen Mikrosporie–Erregern angesehen werden. Die Enzootic wurde durch Griseofulvin–Behandlung und laufende Desinfektion be–herrscht. Summary This report deals with the clinical symptoms, the course and the treatment of an enzootic among gibbon monkeys (Hylobates Lar) imported from Siam. The enzootic was caused by a Microsporum species. The causative agent was isolated from the scales and epilated hairs of the animals as well as from the straw and the walls of the cages. The properties of the cultured fungus resembled in some respects those of M. audouinii, in others those of M. canis. According to recent findings the isolated species is considered to have an intermediary position between M. audouinii and M. canis. As it resembles closely dysgonic strains of M. canis and the variety M. canis–obesum, respectively, it should be considered as belonging to the M. canis–group. Poor growth on rice grains can no longer be regarded as a safe diagnostic procedure for separating M. audouinii from other agents of Microsporum infections. The enzootic was controlled by griseofulvin treatment and by current desinfection of the cages.
H. P. R. Seeliger - One of the best experts on this subject based on the ideXlab platform.
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Über eine Microsporum–Enzootie bei Kappen–Gibbons (Hylobates Lar) verursacht durch eine Variante von Microsporum canis
Mycoses, 2009Co-Authors: H. P. R. Seeliger, W. Bisping, H. P. BrandtAbstract:Zusamenfassung Bericht uber die klinischen Symptome, den Verlauf und die Behandlung einer Mikrosporie–Enzootie bei 8 aus Siam importierten Kappen–Gibbons. Die aus Hautschuppen und Haaren der Tiere sowie aus Mortel und Einstreu der Kafige isolierten Mikrosporie–Erreger wiesen Eigenschaften von M. audouinii und M. canis auf. Aufgrund neuerer Befunde werden sie als ein Intermediartyp zwischen diesen beiden Arten angesehen, der den dysgonen M. canis–Stammen bzw. der M. canis–obesum–Variante weitgehend ahnelt und deshalb als zum Formenkreis von M. canis gehorend anzusehen ist. Die nur sparliche Entwick–lung auf Reiskornern kann nicht mehr als ein sicheres Merkmal zur Trennung des M. audouinii von anderen Mikrosporie–Erregern angesehen werden. Die Enzootic wurde durch Griseofulvin–Behandlung und laufende Desinfektion be–herrscht. Summary This report deals with the clinical symptoms, the course and the treatment of an enzootic among gibbon monkeys (Hylobates Lar) imported from Siam. The enzootic was caused by a Microsporum species. The causative agent was isolated from the scales and epilated hairs of the animals as well as from the straw and the walls of the cages. The properties of the cultured fungus resembled in some respects those of M. audouinii, in others those of M. canis. According to recent findings the isolated species is considered to have an intermediary position between M. audouinii and M. canis. As it resembles closely dysgonic strains of M. canis and the variety M. canis–obesum, respectively, it should be considered as belonging to the M. canis–group. Poor growth on rice grains can no longer be regarded as a safe diagnostic procedure for separating M. audouinii from other agents of Microsporum infections. The enzootic was controlled by griseofulvin treatment and by current desinfection of the cages.
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uber eine microsporum enzootie bei kappen gibbons Hylobates Lar verursacht durch eine variante von microsporum canis
Mycoses, 2009Co-Authors: H. P. R. Seeliger, W. Bisping, H. P. BrandtAbstract:Zusamenfassung Bericht uber die klinischen Symptome, den Verlauf und die Behandlung einer Mikrosporie–Enzootie bei 8 aus Siam importierten Kappen–Gibbons. Die aus Hautschuppen und Haaren der Tiere sowie aus Mortel und Einstreu der Kafige isolierten Mikrosporie–Erreger wiesen Eigenschaften von M. audouinii und M. canis auf. Aufgrund neuerer Befunde werden sie als ein Intermediartyp zwischen diesen beiden Arten angesehen, der den dysgonen M. canis–Stammen bzw. der M. canis–obesum–Variante weitgehend ahnelt und deshalb als zum Formenkreis von M. canis gehorend anzusehen ist. Die nur sparliche Entwick–lung auf Reiskornern kann nicht mehr als ein sicheres Merkmal zur Trennung des M. audouinii von anderen Mikrosporie–Erregern angesehen werden. Die Enzootic wurde durch Griseofulvin–Behandlung und laufende Desinfektion be–herrscht. Summary This report deals with the clinical symptoms, the course and the treatment of an enzootic among gibbon monkeys (Hylobates Lar) imported from Siam. The enzootic was caused by a Microsporum species. The causative agent was isolated from the scales and epilated hairs of the animals as well as from the straw and the walls of the cages. The properties of the cultured fungus resembled in some respects those of M. audouinii, in others those of M. canis. According to recent findings the isolated species is considered to have an intermediary position between M. audouinii and M. canis. As it resembles closely dysgonic strains of M. canis and the variety M. canis–obesum, respectively, it should be considered as belonging to the M. canis–group. Poor growth on rice grains can no longer be regarded as a safe diagnostic procedure for separating M. audouinii from other agents of Microsporum infections. The enzootic was controlled by griseofulvin treatment and by current desinfection of the cages.
Tommaso Savini - One of the best experts on this subject based on the ideXlab platform.
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White-handed gibbons (Hylobates Lar) alter ranging patterns in response to habitat type
Primates, 2020Co-Authors: Lydia E. O. Light, Tommaso Savini, Corey S. Sparks, Thad Q. BartlettAbstract:Small apes are often characterized as inhabiting small home ranges and being dependent on evergreen forest due to their dietary specialization on ripe fruits. Yet few primate studies, particuLarly those with gibbons, have considered intraspecific variations in ranging behaviors in response to local ecological conditions. This study examines Endangered white-handed gibbon ( Hylobates Lar ) ranging patterns in a heterogeneous landscape. We conducted 13 months of behavioral observations on four white-handed gibbon groups living in Huai Kha Khaeng Wildlife Sanctuary in western Thailand, and combine these data with group location and transect-based productivity data. We compare home range area, site fidelity, and microhabitat preferences. Home range (HR) area varied considerably among the four groups (17–61 hectares). Site fidelity was higher in one of the groups with more evergreen forest in the HR (0.72 ± 0.1) than one of the groups with very little evergreen forest in the habitat (0.47 ± 0.07). While groups with more evergreen forest in the HR preferred evergreen forest areas, groups with very little evergreen forest within the HR demonstrated less preference for evergreen forest areas. We conclude that gibbons at this site exhibit a considerable degree of behavioral variation in response to local ecological conditions. These findings suggest that while gibbons exhibit significant ecological flexibility, this flexibility may be limited by habitat type and key food resources.
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varying ecological quality influences the probability of polyandry in white handed gibbons Hylobates Lar in thailand
Biotropica, 2009Co-Authors: Tommaso Savini, Christophe Boesch, Ulrich H ReichardAbstract:Although members of the family Hylobatidae are known to be monogamous, adult white-handed gibbons (Hylobates Lar) at Khao Yai National Park, Thailand, also show multimale groups and polyandry. A need for more than one male to successfully raise offspring cannot explain the occurrence of polyandry in these territorial primates, because direct paternal care is absent in this species. We hypothesize that polyandry is primarily related to costs/benefits for males of cooperatively defending a female and/or resources; our prediction was that polyandry would become more frequent with increasing costs of female/resource defense. We measured the ecological quality of seven gibbon home ranges over a 3-yr period (2001‐2003) to investigate how resource availability affected the probability of polyandry, and found a significant negative relationship between home range quality and home range size. Larger home ranges were of lower quality. As predicted, groups living on Larger, poorer home ranges also experienced longer periods of polyandry. In forest areas of comparatively low quality, acquiring and maintaining a Large home range that includes enough resources for a female to reproduce steadily may surpass a single male’s capacity. Our model of cooperative male polyandry was supported by preliminary data of shared territorial defense and access to the female. However, interaction proportions were strongly skewed, and female’s primary male partners monopolized grooming and mating. Nevertheless, a primary male on a Large territory may benefit from the presence of a secondary male with aid in territorial/female defense, whereas a secondary male may gain by avoiding high dispersal costs.
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Sterile pyuria in a population of wild white-handed gibbons (Hylobates Lar).
American journal of primatology, 2009Co-Authors: Barbara A. Beaman, Tommaso Savini, Wyatt J. Hesemeyer, Nathaniel J. Dominy, Ulrich H ReichardAbstract:Urinalysis is an emerging method for monitoring the health and energy balance of wild primates. Here, we report the first urinalysis of wild gibbons. We used multi-reagent test strips to monitor the health status of 52 individual white-handed gibbons (Hylobates Lar) inhabiting Khao Yai National Park, Thailand. Most urinary reference values were within normal ranges; however, regardless of age- and sex-class or monthly fruit productivity, we found unexpectedly high rates of urinary leukocytes (50% and 90% of individuals in 2001–2003 and 2006, respectively). In contrast to previous studies of African apes, this finding is coupled with the near absence of urinary nitrites, demonstrating pervasive levels of sterile pyuria. This result is the first reported case of sterile pyuria in a population of wild primates. The etiology of human sterile pyuria is diverse, but in all cases it is diagnostic of systemic inflammation. We discuss the potential causes of sterile pyuria in the gibbons of Khao Yai. Am. J. Primatol. 71:880–883, 2009. © 2009 Wiley-Liss, Inc.
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RESEARCH ARTICLE Sterile Pyuria in a Population of Wild White-Handed Gibbons (Hylobates Lar)
2009Co-Authors: Barbara A. Beaman, Tommaso Savini, Wyatt J. Hesemeyer, Nathaniel J. Dominy, Ulrich H ReichardAbstract:Urinalysis is an emerging method for monitoring the health and energy balance of wild primates. Here, we report the first urinalysis of wild gibbons. We used multi-reagent test strips to monitor the health status of 52 individual white-handed gibbons (Hylobates Lar) inhabiting Khao Yai National Park, Thailand. Most urinary reference values were within normal ranges; however, regardless of age- and sex-class or monthly fruit productivity, we found unexpectedly high rates of urinary leukocytes (50% and 90% of individuals in 2001‐2003 and 2006, respectively). In contrast to previous studies of African apes, this finding is coupled with the near absence of urinary nitrites, demonstrating pervasive levels of sterile pyuria. This result is the first reported case of sterile pyuria in a population of wild primates. The etiology of human sterile pyuria is diverse, but in all cases it is diagnostic of systemic inflammation. We discuss the potential causes of sterile pyuria in the gibbons of Khao Yai. Am. J. Primatol. 71:880‐883, 2009. r 2009 Wiley-Liss, Inc.
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Home-range characteristics and the influence of seasonality on female reproduction in white-handed gibbons (Hylobates Lar) at Khao Yai National Park, Thailand
American journal of physical anthropology, 2008Co-Authors: Tommaso Savini, Christophe Boesch, Ulrich H ReichardAbstract:A three-year (2001-2003) study was carried out on the home range characteristics of seven wild white-handed gibbon (Hylobates Lar) groups focusing on the spatio-temporal distribution of food resources at Khao Yai National Park in northeastern Thailand. These results were combined with 23 years (1980-2003) of reproductive performance data on seven females from the same focal groups. Reproductive performance was equal among females with regard to birth, weaning and maturation ratios, and independent of variation in food availability. Offspring mortality, however, was significantly positively correlated with home-range size. In addition, there was an increase in offspring mortality just after weaning, suggesting that the increase in the daily distance traveled by juveniles contributed to this mortality. Conceptions clustered during the first half of the year when food production was at its peak, which presumably allowed females to accumulate sufficient body reserves to resume ovarian cycling. Our results place Khao Yai gibbons closer to Cercopithecidae than great apes in terms of the temporal pattern of reproductive events, though gestation, lactation, inter-birth interval, and offspring maturation are considerably longer in gibbons, placing them closer to the other apes. Our findings underline the unique phylogenetic position of these small-bodied apes in terms of reproductive patterns in primates.