Megan D. Matheson

Grooming, social bonding, and agonistic aiding in rhesus monkeys.

An analysis of simultaneous grooming bouts in a captive group of rhesus monkeys (Macaca mulatta) failed to provide evidence of competition to groom high ranking partners. Not only were grooming supplantations rare, but the highest ranking individuals performing grooming did not groom the highest ranking animals receiving grooming. Lower ranking partners, however, did more grooming in nonkin dyads. Grooming partners aided one another in agonistic episodes, but the individual receiving the aid did not groom the individual providing the aid more than vice versa. Kin dyads did aid and groom one another at greater than expected rates, but the aider did not receive the greater proportion of grooming in the dyad. Males participated in more grooming than expected, but their grooming was not related to aiding either with regard to one another or female partners. Animals that were targeted in joint aggression, or aided against, received significantly less grooming from their opponents. A general social relationship expressed in partner preferences, social grooming, and agonistic aiding better explained the observed pattern than any model based on the exchange of services for favors in different currencies. Am. J. Primatol. 51:177–186, 2000.

Conflict and post-conflict behavior in a small group of chimpanzees.

Chimpanzee research plays a central role in the discussions of conflict negotiation. Reconciliation, or the attraction and affiliation of former opponents following conflict, has been proposed as a central element of conflict negotiation in chimpanzees and various other taxa. In an attempt to expand the database of chimpanzee conflict resolution, conflict and post-conflict behavior were recorded for a small group of socially housed chimpanzees at the Chimpanzee and Human Communication Institute, at Central Washington University. Data were collected over six 6-week periods between 1997 and 2000, for a total of 840 hours of observation, resulting in a substantial post-conflict (PC) and matched control (MC) data set. The data demonstrate this group’s tendencies to maintain visual contact and closer proximity after conflicts. Dyadic corrected conciliatory tendencies ranged between 0 – 37.5% and averaged 17.25% across all dyads. Individual corrected conciliatory tendencies ranged between 5.8 and 32%. The results of this study combined with recent publications on captive and free-ranging chimpanzee post-conflict behavior suggest that variation in post-conflict behavior may be important to our understanding of chimpanzee conflict negotiation, and may also have implications for the design and management of captive chimpanzee enclosures and social groups, respectively.

Sequences of Tibetan Macaque (Macaca thibetana) and Tourist Behaviors at Mt. Huangshan, China

Abstract: Previous research on Tibetan macaques (Macaca thibetana) at Mt. Huangshan, China, suggested that ecotourism can have detrimental consequences. This study identified sequences of behaviors that typically occur in macaque-tourist interactions to examine whether particular tourist behaviors precipitate monkey responses. Focal sampling was used to record relevant behaviors from tourists and 10 macaques over 28 data collection sessions in August 2006. Data collectors recorded whether each behavior occurred as part of a sequence. Sequences were defined as two or more behaviors in which each behavior occurred within five seconds of the previous behavior. Of 3,129 total behaviors, 2,539 (81.1%) were from tourists and 590 (18.9%) were from monkeys. Tourists initiated significantly more sequences than did macaques (412 [84.6%] versus 75 [15.4%]). Tourist pointing, rail slapping, fleeing, and rock showing occurred significantly more than expected in tourist-macaque sequences. Points were also among the most common tourist behaviors preceding macaque threats. By discouraging tourists from engaging in these behaviors, macaque threats could be reduced, thereby improving macaque-tourist interactions. These results may aid in the management of other macaque tourist sites to minimize stress-inducing interactions.

Grooming reciprocity in male Tibetan macaques

In several primate species, adult males are reported to compete for access to reproductive partners as well as forming affiliative and cohesive social bonds based on the exchange of goods or services. We hypothesized that among a broad set of fitness‐maximizing strategies, grooming can be used by individual adult males to enhance social relationships through reciprocity and/or through the interchange of grooming for a different but equivalent good or service. We used focal animal sampling and continuously recorded dyadic grooming and agonistic interactions to test a series of predictions regarding male social interactions in a free‐ranging group of Tibetan macaques (Macaca thibetana) at Huangshan, China. During the non‐mating season or between males of similar rank throughout the year, grooming effort given was matched by grooming effort received. However, lower ranking males groomed higher ranking males at a greater rate and/or for a longer duration during both the mating and non‐mating periods. We found that higher ranking males directed less aggression towards males with whom they formed a frequent grooming partnership, indicating that grooming received was interchanged for increased social tolerance. These data suggest that individual male Tibetan macaques employ alternative social strategies associated with grooming reciprocity or interchange depending on dominance rank and rates of aggression, and highlight the importance of both biological markets and grooming reciprocity as behavioral mechanisms used by resident adult males to form and maintain affiliative social bonds. Am. J. Primatol. 75:1009–1020, 2013.

Tourist impact on Tibetan macaques.

Abstract Ecotourism is a growing sector of the tourism industry, but few studies to date have quantified its impacts on local people, tourists and wildlife. We present a preliminary study on threat and affiliative behaviors of two groups of free-ranging Tibetan macaques (Macaca thibetana) as a function of habituation and tourist presence. Data indicate that the less habituated group spent less time within sight of tourists compared with the more habituated group. The more habituated group engaged in frequent affiliative behaviors while within sight of humans, whereas affiliative behavior was not observed in the less habituated group. The general pattern of threats consisted of adults primarily threatening juveniles and juveniles primarily threatening humans, possibly due to redirection. No clear pattern of threats as a function of tourist density emerged. Tourist feeding, although discouraged, potentially provided a catalyst for some aggression. Future research will focus on clarifying which human behaviors evoke specific threat responses from monkeys. These data will be used to refine the existing management plan for this monkey population.

Seasonal variation and synchronization of sexual behaviors in free-ranging male Tibetan macaques (Macaca thibetana) at Huangshan, China

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.

Response to novel housing in two groups of captive tufted capuchin monkeys (Cebus apella)

The influence of age, maternal status, and the presence of a group male on use of space was assessed in two groups of captive tufted capuchin monkeys that underwent a move from indoor housing to a larger outdoor facility. Both groups originally contained two adult males, but only one group retained a male after the move. Following the move, mothers spent less time on the ground when carrying their infants than they did when not carrying their infants. In the group with no male (1) individuals decreased time spent on the ground relative to pre-move levels, whereas no such difference was noted in the group with the male; (2) females spent more time carrying their infants than did females in the group with a male. In the group with the adult male, juveniles spent less time on the ground than did non-mother adult females, whereas no difference had existed prior to the move. Grooming rates dropped from pre-move to post-move, but the mean number of partners with which each animal was in contact increased. Measures of social behavior varied across post-move observation periods inversely to time spent on the ground. These results are consistent with the view that an individual’s relative vulnerability influences behavioral conservatism in novel environments, and suggests a relatively profound role for males in promoting exploration of new space in this species.

Social Contact Following Severe Aggression in Rhesus Macaques (Macaca mulatta): A New Test of the Consolation Hypothesis

Previous studies on macaque species revealed no evidence of consolation: affiliative contact between the loser of an aggressive interaction and a third party. However, typically, the researchers used short observation periods and latency to make first affiliative contact as a dependent measure. Based on social stress buffering literature, I predicted that by employing longer observation periods and percentage of time in affiliative contact as a dependent measure, I would be more likely to detect increases in affiliative contact following aggression. I observed adult female rhesus macaques for 1 hr after they received severe aggression and for 1 hr after some affiliative contact, and measured time spent in affiliative contact using instantaneous recording at 30-sec intervals. Contrary to prediction, victims of attack did not spend a greater percentage of time in affiliative contact postaggression as compared to postaffiliation. Subjects were also less likely to initiate contact with other individuals and were more likely to have contact with individuals that were dominant to their aggressor, following aggression. These results provide converging evidence that affiliative contact is not increased following aggression in macaques. I discuss the failure to bear out the predictions based on the social stress buffering literature in terms of rhesus social dynamics, the nature of aggression as a stressor, and possible mechanisms for the social stress buffering effect.