Primate play is an important feature of physical and cognitive development. Functions of play inc... more Primate play is an important feature of physical and cognitive development. Functions of play include facilitating development of motor and cognitive abilities, providing opportunities to practice adult skills, and learning social roles. Previous research indicates differences among age and sex classes for type and amount of play, suggesting that primates modify play behaviors in relation to adult social roles. Other play research has highlighted preference for a play partner within the same age and sex class, which is also in concordance with the play’s function in learning adult social roles. Tibetan macaques (Macaca thibetana) have been studied in relation to their social hierarchy and sexual behaviors, but there has been no study of juvenile play behavior. We investigated play among Tibetan macaque infants, juvenile females, and juvenile males. We collected three minute focal samples and scored play behaviors using an ethogram. We hypothesized differences would exist in type and amount of play between age and sex classes and that individuals would prefer same age/sex play partners. Results showed that infants spent more time playing (N=39.87%) than did juvenile males (N=16.00%) and females (N=14.73%). There is a trend for partners of the same age class to play. All age and sex classes engaged in a wide variety of sexual play behaviors. Overall, there were differences in the variety of play observed among macaque age and sex classes. We also noted ontogenetic shifts in behaviors as individuals transitioned into adulthood
Gestural communication of large-bodied apes has been extensively studied, however data on small-b... more Gestural communication of large-bodied apes has been extensively studied, however data on small-bodied ape communication are less common. We explored gestures used in commun,ication by captive Javan gibbons (Hylobates moloch) housed at the Gibbon Conservation Center in Santa Clarita, California. We hypothesized that a sender gibbon’s gesture modality would vary with the recipient gibbon’s attentional state. We predicted that senders would be equally likely to use all gesture modalities (i.e., tactile, visual, actions, and facial expressions) when the recipient was attending or facing the sender, but would be biased toward tactile gestures and actions when the recipient was non-attending or oriented away from the sender. We collected data from three gibbon groups, n=10 individuals, using all-occurrences sampling and an ethogram to score behaviors from digital video recordings. Occurrences of gestures through the four modalities were recorded during a gibbon’s attempt to interact with another group member. We observed 1,143 interactions over 20 days. When all data were aggregated, gibbons used visual gestures, t(18)=2.79, p=0.01, and facial expressions, t(18)=2.60, p=0.02, significantly more when the recipient was attending and used tactile gestures, t(17)=2.47, p=0.02, significantly more when the recipient was non-attending. There was no significant difference in the actions modality, t(18)=0.82, p= 0.43. These data show that Javan gibbons used gestures that are appropriate to the recipient’s attentional state in three out of the four modalities
Generally,gibbons are monogamous and territorial,mean group size is about four.But with the dispu... more Generally,gibbons are monogamous and territorial,mean group size is about four.But with the disputable species of black-crested gibbon (Hylobates concolor) based on recent ecological studies,the mean group size vairied from 3 to 7 or 8 according to different studies,and the mating system was considered to be monogamous or polygynous (Xu et al.,1983;Haimoff et al.,1986;Liu,1988;Lan,1989).This article mainly deals with the black-gibbons group size and composition,after a 10-month survey of black-crested gibbons in Wuliang and Ailao Reserve,Yunnan Province.We concluded from seven groups in 4 sites that mean group size is 4.3,each group has 1 adult male,1-2 adult females,and 1-3 offspring of various ages.The group size and composition is similar with that of Hainan black-crested gibbon reported by Xu et al(1983) and Liu (1988),but the results show some differences with Haimoff et al (1986) and Lan (1989).The group size and compositioon are quite correlated with the habitat,e.g.,GC1 group and GD group live in the less disturbed area,each maintians a group of six or seven individuals including two adult females respectively,and GG group only has one adult female and one subadult male because of heavy hunting presure and forest cutting in their habitat,althouth they live in more than 200 hm[2].
Bridging is an affiliative interaction in which two individuals lift an infant between them and l... more Bridging is an affiliative interaction in which two individuals lift an infant between them and lick the infant’s genitals. Male-male bridging and similar affiliative behaviors have been studied in several macaque (Macaca) species, but female-female bridging has received less focus. Male-male bridging is hypothesized to reduce social tension between individuals, but it may function differently for females. We studied female-female bridging in provisioned Tibetan macaques (M. thibetana) from August to September 2014. We predicted that female-female bridging would show distinct patterns when compared to what has been reported for males. We recorded bridging behavior from an ethogram using all-occurrence and focal animal sampling of eight adult and four subadult females. Similar to what has been observed for males, female-female bridges were never immediately followed by aggression, and females used infants as the “bridge” more often than they used juveniles. Unlike what has been repor...
Until now, mother-infant relationships have not been studied in a wild population of the Southern... more Until now, mother-infant relationships have not been studied in a wild population of the Southern Pig-tailed Macaques Macaca nemestrina. We observed six mother-infant dyads from April 2016 to September 2016 in the Segari Melintang Forest Reserve, Peninsular Malaysia using focal sampling methods from the perspectives of both individuals. We hypothesized that as infant age increased, the same important mother-infant behaviours, previously observed to change in captive pig-tailed macaque mother-infant studies, would also change over time in field conditions. We expected that as the infant ages, mothers would decrease their rates of restraint and retrieval, and increase their rates of punishment. Two separate generalized linear mixed models (GLMM) of mother permissive behaviour and mother-infant contact duration as the outcome variables each showed infant age as the sole significant predictor variable indicating that as infant age increased, maternal behaviours changed as expected above...
ABSTRACT In: Mittermeier RA, Rylands AB, Wilson DE (eds.) Handbook of the Mammals of the World. V... more ABSTRACT In: Mittermeier RA, Rylands AB, Wilson DE (eds.) Handbook of the Mammals of the World. Vol. 3 Primates. Lynx Edicions, Barcelona. Pp 550-627.
Until now, mother-infant relationships have not been studied in a wild population of the Southern... more Until now, mother-infant relationships have not been studied in a wild population of the Southern Pig-tailed Macaques Macaca nemestrina. We observed six mother-infant dyads from April 2016 to September 2016 in the Segari Melintang Forest Reserve, Peninsular Malaysia using focal sampling methods from the perspectives of both individuals. We hypothesized that as infant age increased, the same important mother-infant behaviours, previously observed to change in captive pig-tailed macaque mother-infant studies, would also change over time in field conditions. We expected that as the infant ages, mothers would decrease their rates of restraint and retrieval, and increase their rates of punishment. Two separate generalized linear mixed models (GLMM) of mother permissive behaviour and mother-infant contact duration as the outcome variables each showed infant age as the sole significant predictor variable indicating that as infant age increased, maternal behaviours changed as expected above...
Golden langurs (Trachypithecus geei) in Bhutan have received little research attention in the ant... more Golden langurs (Trachypithecus geei) in Bhutan have received little research attention in the anthropic environments where most of the population lives. We recorded group sizes and compositions and documented sleep sites for 24 golden langur groups living in a biological corridor (N = 9) and near a human settlement (N = 15) in central Bhutan. We used scan sampling to document behaviors and direct observation and camera traps to record potential predators, and we recorded occurrences of mortality, including two cases of electrocution, one case of roadkill, and one langur skull recovered from a possible leopard prey cache. Golden langur groups were on average significantly larger near human settlements (13.73 individuals) than in the biological corridor (9.55 individuals), and the adult sex ratio was greater near human settlements. The golden langurs usually slept in more than one tree, and our preliminary results indicated rare re-use of the same sleep site. Golden langurs in our stu...
Variation in the availability and distribution of food resources is a strong selective pressure o... more Variation in the availability and distribution of food resources is a strong selective pressure on wild primates. We explored variation in Tibetan macaque gut microbiota composition during winter and spring seasons. Our results showed that gut microbial composition and diversity varied by season. In winter, the genus Succinivibrio, which promotes the digestion of cellulose and hemicellulose, was significantly increased. In spring, the abundance of the genus Prevotella, which is associated with digestion of carbohydrates and simple sugars, was significantly increased. PICRUSt analysis revealed that the predicted metagenomes related to the glycan biosynthesis and metabolic pathway was significantly increased in winter samples, which would aid in the digestion of glycan extracted from cellulose and hemicellulose. The predicted metagenomes related to carbohydrate and energy metabolic pathways were significantly increased in spring samples, which could facilitate a monkey's recovery ...
Research on leadership is a critical step for understanding collective decision making. However, ... more Research on leadership is a critical step for understanding collective decision making. However, only 4 of the 22 extant macaque species have been examined for the impact of social rank and affiliation on the initiation of collective movement. It is far from clear whether such impact exists and, if so, how it works among other macaques. To answer these questions, we investigated free-ranging, Tibetan macaques' (Macaca thibetana) group departures from a provisioning area and tested two alternative hypotheses: personal versus distributed leadership. Personal leadership predicts that a single, highest ranking individual initiates the most group movements, whereas distributed leadership predicts that different members lead the group on different occasions and affiliative individuals have more initiations. We recorded how often and how successfully adults initiated group movements from a provisioning area into the forest, and related these variables to the duration of interindividual...
To further the potential for applied personality studies, we present a methodology for assessing ... more To further the potential for applied personality studies, we present a methodology for assessing personality in nonhuman animals without a priori assumptions, using behavioral measures to discriminate personality survey results. Our study group consisted of 12 free-ranging, provisioned, adult Tibetan macaques Macaca thibetana at the Valley of the Wild Monkeys, China. We asked familiar Chinese park guards and scientists to rate each of the 12 macaques using 27-item personality surveys. We also recorded behavioral observations (> 100 hrs) from August–September, 2012. The personality surveys showed reliability in 22 of the items that were then utilized in a principal component analysis that revealed five components: Insecurity, Reactivity, Boldness, Sociability, and Leadership. Prior personality research on Macaca show comparable components. In order to determine which behaviors would best predict those five personality components, we conducted discriminant analyses using behavioral...
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji, 2014
Adult male Tibetan (Macaca thibetana), Barbary (M. sylvanus), and stump-tailed macaques (M. arcto... more Adult male Tibetan (Macaca thibetana), Barbary (M. sylvanus), and stump-tailed macaques (M. arctoides) engage in bridging, a ritualized infant-handling behavior. Previous researchers found a bias toward the use of male infants for this behavior, but its function is debated. Explanations include three hypotheses: paternal care, mating effort, and agonistic buffering. We studied a group of habituated, provisioned Tibetan macaques to test whether adult males' affiliative relationships with females predicted their use of an infant for bridging. We also examined biases for sex, age, and individual in males' choice of bridging infant. We collected data via all occurrences, focal animal, and scan methods, from August to September 2011 at the Valley of the Wild Monkeys, China. We found that male infants were significantly preferred over females for bridging, but of three male infants in the group, only one was used by all males, while one male infant was used less often than expecte...
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji, 2010
Although seasonal breeding has been documented in many non-human primates, it is not clear whethe... more Although seasonal breeding has been documented in many non-human primates, it is not clear whether sexual behaviors show seasonal variation among male individuals. To test this hypothesis, the focal animal sampling method and continuous recording were used to investigate seasonal variation and synchronization of sexual behaviors in five male Tibetan macaques (Macaca thibetana) at Mt. Huangshan from Oct 2005 to Sept 2006. Both copulatory and sexually motivated behaviors (i.e., sexual chase, grimace, and sexual-inspection), which were significantly higher in the mating season than non-mating season. Furthermore, seasonal variations of sexual behaviors, including copulatory and sexually motivated behaviors, were synchronized among males. The results shed light on sexual competition and tactics for reproductive success of male M. thibetana and other non-human primates with seasonal breeding.
Primate play is an important feature of physical and cognitive development. Functions of play inc... more Primate play is an important feature of physical and cognitive development. Functions of play include facilitating development of motor and cognitive abilities, providing opportunities to practice adult skills, and learning social roles. Previous research indicates differences among age and sex classes for type and amount of play, suggesting that primates modify play behaviors in relation to adult social roles. Other play research has highlighted preference for a play partner within the same age and sex class, which is also in concordance with the play’s function in learning adult social roles. Tibetan macaques (Macaca thibetana) have been studied in relation to their social hierarchy and sexual behaviors, but there has been no study of juvenile play behavior. We investigated play among Tibetan macaque infants, juvenile females, and juvenile males. We collected three minute focal samples and scored play behaviors using an ethogram. We hypothesized differences would exist in type and amount of play between age and sex classes and that individuals would prefer same age/sex play partners. Results showed that infants spent more time playing (N=39.87%) than did juvenile males (N=16.00%) and females (N=14.73%). There is a trend for partners of the same age class to play. All age and sex classes engaged in a wide variety of sexual play behaviors. Overall, there were differences in the variety of play observed among macaque age and sex classes. We also noted ontogenetic shifts in behaviors as individuals transitioned into adulthood
Gestural communication of large-bodied apes has been extensively studied, however data on small-b... more Gestural communication of large-bodied apes has been extensively studied, however data on small-bodied ape communication are less common. We explored gestures used in commun,ication by captive Javan gibbons (Hylobates moloch) housed at the Gibbon Conservation Center in Santa Clarita, California. We hypothesized that a sender gibbon’s gesture modality would vary with the recipient gibbon’s attentional state. We predicted that senders would be equally likely to use all gesture modalities (i.e., tactile, visual, actions, and facial expressions) when the recipient was attending or facing the sender, but would be biased toward tactile gestures and actions when the recipient was non-attending or oriented away from the sender. We collected data from three gibbon groups, n=10 individuals, using all-occurrences sampling and an ethogram to score behaviors from digital video recordings. Occurrences of gestures through the four modalities were recorded during a gibbon’s attempt to interact with another group member. We observed 1,143 interactions over 20 days. When all data were aggregated, gibbons used visual gestures, t(18)=2.79, p=0.01, and facial expressions, t(18)=2.60, p=0.02, significantly more when the recipient was attending and used tactile gestures, t(17)=2.47, p=0.02, significantly more when the recipient was non-attending. There was no significant difference in the actions modality, t(18)=0.82, p= 0.43. These data show that Javan gibbons used gestures that are appropriate to the recipient’s attentional state in three out of the four modalities
Generally,gibbons are monogamous and territorial,mean group size is about four.But with the dispu... more Generally,gibbons are monogamous and territorial,mean group size is about four.But with the disputable species of black-crested gibbon (Hylobates concolor) based on recent ecological studies,the mean group size vairied from 3 to 7 or 8 according to different studies,and the mating system was considered to be monogamous or polygynous (Xu et al.,1983;Haimoff et al.,1986;Liu,1988;Lan,1989).This article mainly deals with the black-gibbons group size and composition,after a 10-month survey of black-crested gibbons in Wuliang and Ailao Reserve,Yunnan Province.We concluded from seven groups in 4 sites that mean group size is 4.3,each group has 1 adult male,1-2 adult females,and 1-3 offspring of various ages.The group size and composition is similar with that of Hainan black-crested gibbon reported by Xu et al(1983) and Liu (1988),but the results show some differences with Haimoff et al (1986) and Lan (1989).The group size and compositioon are quite correlated with the habitat,e.g.,GC1 group and GD group live in the less disturbed area,each maintians a group of six or seven individuals including two adult females respectively,and GG group only has one adult female and one subadult male because of heavy hunting presure and forest cutting in their habitat,althouth they live in more than 200 hm[2].
Bridging is an affiliative interaction in which two individuals lift an infant between them and l... more Bridging is an affiliative interaction in which two individuals lift an infant between them and lick the infant’s genitals. Male-male bridging and similar affiliative behaviors have been studied in several macaque (Macaca) species, but female-female bridging has received less focus. Male-male bridging is hypothesized to reduce social tension between individuals, but it may function differently for females. We studied female-female bridging in provisioned Tibetan macaques (M. thibetana) from August to September 2014. We predicted that female-female bridging would show distinct patterns when compared to what has been reported for males. We recorded bridging behavior from an ethogram using all-occurrence and focal animal sampling of eight adult and four subadult females. Similar to what has been observed for males, female-female bridges were never immediately followed by aggression, and females used infants as the “bridge” more often than they used juveniles. Unlike what has been repor...
Until now, mother-infant relationships have not been studied in a wild population of the Southern... more Until now, mother-infant relationships have not been studied in a wild population of the Southern Pig-tailed Macaques Macaca nemestrina. We observed six mother-infant dyads from April 2016 to September 2016 in the Segari Melintang Forest Reserve, Peninsular Malaysia using focal sampling methods from the perspectives of both individuals. We hypothesized that as infant age increased, the same important mother-infant behaviours, previously observed to change in captive pig-tailed macaque mother-infant studies, would also change over time in field conditions. We expected that as the infant ages, mothers would decrease their rates of restraint and retrieval, and increase their rates of punishment. Two separate generalized linear mixed models (GLMM) of mother permissive behaviour and mother-infant contact duration as the outcome variables each showed infant age as the sole significant predictor variable indicating that as infant age increased, maternal behaviours changed as expected above...
ABSTRACT In: Mittermeier RA, Rylands AB, Wilson DE (eds.) Handbook of the Mammals of the World. V... more ABSTRACT In: Mittermeier RA, Rylands AB, Wilson DE (eds.) Handbook of the Mammals of the World. Vol. 3 Primates. Lynx Edicions, Barcelona. Pp 550-627.
Until now, mother-infant relationships have not been studied in a wild population of the Southern... more Until now, mother-infant relationships have not been studied in a wild population of the Southern Pig-tailed Macaques Macaca nemestrina. We observed six mother-infant dyads from April 2016 to September 2016 in the Segari Melintang Forest Reserve, Peninsular Malaysia using focal sampling methods from the perspectives of both individuals. We hypothesized that as infant age increased, the same important mother-infant behaviours, previously observed to change in captive pig-tailed macaque mother-infant studies, would also change over time in field conditions. We expected that as the infant ages, mothers would decrease their rates of restraint and retrieval, and increase their rates of punishment. Two separate generalized linear mixed models (GLMM) of mother permissive behaviour and mother-infant contact duration as the outcome variables each showed infant age as the sole significant predictor variable indicating that as infant age increased, maternal behaviours changed as expected above...
Golden langurs (Trachypithecus geei) in Bhutan have received little research attention in the ant... more Golden langurs (Trachypithecus geei) in Bhutan have received little research attention in the anthropic environments where most of the population lives. We recorded group sizes and compositions and documented sleep sites for 24 golden langur groups living in a biological corridor (N = 9) and near a human settlement (N = 15) in central Bhutan. We used scan sampling to document behaviors and direct observation and camera traps to record potential predators, and we recorded occurrences of mortality, including two cases of electrocution, one case of roadkill, and one langur skull recovered from a possible leopard prey cache. Golden langur groups were on average significantly larger near human settlements (13.73 individuals) than in the biological corridor (9.55 individuals), and the adult sex ratio was greater near human settlements. The golden langurs usually slept in more than one tree, and our preliminary results indicated rare re-use of the same sleep site. Golden langurs in our stu...
Variation in the availability and distribution of food resources is a strong selective pressure o... more Variation in the availability and distribution of food resources is a strong selective pressure on wild primates. We explored variation in Tibetan macaque gut microbiota composition during winter and spring seasons. Our results showed that gut microbial composition and diversity varied by season. In winter, the genus Succinivibrio, which promotes the digestion of cellulose and hemicellulose, was significantly increased. In spring, the abundance of the genus Prevotella, which is associated with digestion of carbohydrates and simple sugars, was significantly increased. PICRUSt analysis revealed that the predicted metagenomes related to the glycan biosynthesis and metabolic pathway was significantly increased in winter samples, which would aid in the digestion of glycan extracted from cellulose and hemicellulose. The predicted metagenomes related to carbohydrate and energy metabolic pathways were significantly increased in spring samples, which could facilitate a monkey's recovery ...
Research on leadership is a critical step for understanding collective decision making. However, ... more Research on leadership is a critical step for understanding collective decision making. However, only 4 of the 22 extant macaque species have been examined for the impact of social rank and affiliation on the initiation of collective movement. It is far from clear whether such impact exists and, if so, how it works among other macaques. To answer these questions, we investigated free-ranging, Tibetan macaques' (Macaca thibetana) group departures from a provisioning area and tested two alternative hypotheses: personal versus distributed leadership. Personal leadership predicts that a single, highest ranking individual initiates the most group movements, whereas distributed leadership predicts that different members lead the group on different occasions and affiliative individuals have more initiations. We recorded how often and how successfully adults initiated group movements from a provisioning area into the forest, and related these variables to the duration of interindividual...
To further the potential for applied personality studies, we present a methodology for assessing ... more To further the potential for applied personality studies, we present a methodology for assessing personality in nonhuman animals without a priori assumptions, using behavioral measures to discriminate personality survey results. Our study group consisted of 12 free-ranging, provisioned, adult Tibetan macaques Macaca thibetana at the Valley of the Wild Monkeys, China. We asked familiar Chinese park guards and scientists to rate each of the 12 macaques using 27-item personality surveys. We also recorded behavioral observations (> 100 hrs) from August–September, 2012. The personality surveys showed reliability in 22 of the items that were then utilized in a principal component analysis that revealed five components: Insecurity, Reactivity, Boldness, Sociability, and Leadership. Prior personality research on Macaca show comparable components. In order to determine which behaviors would best predict those five personality components, we conducted discriminant analyses using behavioral...
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji, 2014
Adult male Tibetan (Macaca thibetana), Barbary (M. sylvanus), and stump-tailed macaques (M. arcto... more Adult male Tibetan (Macaca thibetana), Barbary (M. sylvanus), and stump-tailed macaques (M. arctoides) engage in bridging, a ritualized infant-handling behavior. Previous researchers found a bias toward the use of male infants for this behavior, but its function is debated. Explanations include three hypotheses: paternal care, mating effort, and agonistic buffering. We studied a group of habituated, provisioned Tibetan macaques to test whether adult males' affiliative relationships with females predicted their use of an infant for bridging. We also examined biases for sex, age, and individual in males' choice of bridging infant. We collected data via all occurrences, focal animal, and scan methods, from August to September 2011 at the Valley of the Wild Monkeys, China. We found that male infants were significantly preferred over females for bridging, but of three male infants in the group, only one was used by all males, while one male infant was used less often than expecte...
Dong wu xue yan jiu = Zoological research / "Dong wu xue yan jiu" bian ji wei yuan hui bian ji, 2010
Although seasonal breeding has been documented in many non-human primates, it is not clear whethe... more Although seasonal breeding has been documented in many non-human primates, it is not clear whether sexual behaviors show seasonal variation among male individuals. To test this hypothesis, the focal animal sampling method and continuous recording were used to investigate seasonal variation and synchronization of sexual behaviors in five male Tibetan macaques (Macaca thibetana) at Mt. Huangshan from Oct 2005 to Sept 2006. Both copulatory and sexually motivated behaviors (i.e., sexual chase, grimace, and sexual-inspection), which were significantly higher in the mating season than non-mating season. Furthermore, seasonal variations of sexual behaviors, including copulatory and sexually motivated behaviors, were synchronized among males. The results shed light on sexual competition and tactics for reproductive success of male M. thibetana and other non-human primates with seasonal breeding.
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