Parameters of Experimental Activity in the Study of the Cognitive Abilities of Rhesus Monkeys (Macaca mulatta) and Baboons (Papio hamadryas).

We compared experimental activity, behavioral activity in the experiment, of rhesus monkeys (Macaca mulatta) and baboons (Papio hamadryas). Baboons showed higher levels of experimental activity. The contrast in the activity between the species is probably associated with species-specific characteristics of the behavior and different ability to adapt under new conditions. In particular, they may be the result of lower plasticity of rhesus monkeys with respect to experimental conditions.

Social evolution in Plio-Pleistocene hominins: Insights from hamadryas baboons and paleoecology.

Reconstructions of hominin evolution have long benefited from comparisons with nonhuman primates, especially baboons and chimpanzees. The hamadryas baboon (Papio hamadryas) is arguably one of the best such models, as it exhibits both the male kin bonding and the cross-sex pair bonding thought to have been important in hominin evolution. Here we link processes of behavioral evolution in hamadryas baboons with those in a Plio-Pleistocene hominin, provisionally identified as Homo erectus (sensu lato) - a pivotal species in that its larger body and brain size and wider ranging patterns increased female costs of reproduction, increasing the importance of sociality. The combination of these higher costs of reproduction and shifts in diet and food acquisition have previously been argued to have been alleviated either via strengthening of male-female bonds (involving male provisioning and the evolution of monogamy) or via the assistance of older, post-reproductive females (leading to post-reproductive longevity in females, i.e., the grandmother hypothesis). We suggest that both arrangements could have been present in Plio-Pleistocene hominins if they lived in multilevel societies. Here we expand on our earlier scenario with two sets of recent data in support of it, (1) archaeological data from the 2 million year old Oldowan site of Kanjera South, Kenya and other sites that are suggestive of tool dependent foraging on nutrient dense resources (animal carcasses and plant underground storage organs), cooperation, and food sharing; and (2) a pattern of genetic variation in hamadryas baboons that suggests the operation of kin selection among both males and females at multiple levels of society. Taken together, these two sets of data strengthen our model and support the idea of a complex society linked by male-male, male-female, and female-female bonds at multiple levels of social organization in Plio-Pleistocene hominins.

Group compositional changes impact the social and feeding behaviors of captive hamadryas baboons (Papio hamadryas hamadryas).

The formation and modification of social groups in captivity are delicate management tasks. The ability for personnel to anticipate changes in group dynamics following compositional changes can increase the likelihood of successful management with minimized injury or social instability. Hamadryas baboons (Papio hamadryas hamadryas) have a distinctive multi-level social system comprising of one-male units (OMUs) that can make it difficult to apply knowledge from other primates' multi-female/multi-male social structure to changes imposed onto captive hamadryas baboon groups. We conducted an observational study of the behavioral impacts following the introduction of two females into the group of hamadryas baboons at the Wildlife Conservation Society's Prospect Park Zoo in NY to test hypotheses about the relationships between changes in group composition and social and feeding behavior. Generalized linear mixed models demonstrated that social interactions significantly increased following the compositional changes, even in groups that only experienced member removals. The increase in affiliative social behavior observed suggests that during times of social stress or uncertainty, hamadryas baboons may employ social behavior as a tension-reducing mechanism to negotiate relationships as opposed to using aggression to engage in competitions for ranks and resources. The observed response to compositional changes implies that hamadryas baboons may respond with less aggression than do other Old World monkey species and that levels of affiliative behavior may be a more accurate metric for evaluating introduction success in hamadryas baboons.

The rise and fall of leader males in a multi-level society: takeovers and tenures of male Hamadryas baboons.

As one means to maximize access to females, males of some species are intolerant of other males in social units, resulting in female defense polygyny, a mating system in which one male monopolizes mating access to as many females as he can for as long as possible. In such a system, the length of a male's tenure and the number of females he is able to acquire are important predictors of his reproductive success. Hamadryas baboons differ from many other taxa with female defense polygyny in that they acquire and lose females individually, thus patterns of acquisition and loss of females over time are additional factors contributing to a male's fitness. Here, we describe longitudinal patterns of female acquisition and loss over a 9-year period in a group of 250 wild hamadryas baboons. Complete tenures of leader males ranged from 310 to 2,160 days (N = 13) and results from a survival analysis yielded a median tenure length of 2,160 days, or 6 years (N = 49). The total number of females acquired, which increased with tenure length, ranged from 1 to 14 and averaged 3.5, and leader males acquired females both opportunistically and via challenging other males. The interval between acquisition of successive females ranged from 0 to 1,196 days with a median of 203, and males acquired all of their females less than halfway into their tenure. Females from outside of a leader male's social sphere (clan and band) were acquired relatively later in their tenure compared to females from within a male's social sphere. Leaders typically lost females gradually during the latter part of their tenure or all (or most) at once, suggesting an inverted U-shaped longitudinal arc of male competitive ability.

Recurrent patterning in the daily foraging routes of hamadryas baboons (Papio hamadryas): spatial memory in large-scale versus small-scale space.

The benefits of spatial memory for foraging animals can be assessed on two distinct spatial scales: small-scale space (travel within patches) and large-scale space (travel between patches). While the patches themselves may be distributed at low density, within patches resources are likely densely distributed. We propose, therefore, that spatial memory for recalling the particular locations of previously visited feeding sites will be more advantageous during between-patch movement, where it may reduce the distances traveled by animals that possess this ability compared to those that must rely on random search. We address this hypothesis by employing descriptive statistics and spectral analyses to characterize the daily foraging routes of a band of wild hamadryas baboons in Filoha, Ethiopia. The baboons slept on two main cliffs--the Filoha cliff and the Wasaro cliff--and daily travel began and ended on a cliff; thus four daily travel routes exist: Filoha-Filoha, Filoha-Wasaro, Wasaro-Wasaro, Wasaro-Filoha. We use newly developed partial sum methods and distribution-fitting analyses to distinguish periods of area-restricted search from more extensive movements. The results indicate a single peak in travel activity in the Filoha-Filoha and Wasaro-Filoha routes, three peaks of travel activity in the Filoha-Wasaro routes, and two peaks in the Wasaro-Wasaro routes; and are consistent with on-the-ground observations of foraging and ranging behavior of the baboons. In each of the four daily travel routes the "tipping points" identified by the partial sum analyses indicate transitions between travel in small- versus large-scale space. The correspondence between the quantitative analyses and the field observations suggest great utility for using these types of analyses to examine primate travel patterns and especially in distinguishing between movement in small versus large-scale space. Only the distribution-fitting analyses are inconsistent with the field observations, which may be due to the scale at which these analyses were conducted.

Abnormal behavior and associated risk factors in captive baboons (Papio hamadryas spp.).

Abnormal behavior, ranging from motor stereotypies to self-injurious behavior, has been documented in captive nonhuman primates, with risk factors including nursery rearing, single housing, and veterinary procedures. Much of this research has focused on macaque monkeys; less is known about the extent of and risk factors for abnormal behavior in baboons. Because abnormal behavior can be indicative of poor welfare, either past or present, the purpose of this study was to survey the presence of abnormal behavior in captive baboons and to identify potential risk factors for these behaviors with an aim of prevention. Subjects were 144 baboons (119 females, 25 males) aged 3-29 (median = 9.18) years temporarily singly housed for research or clinical reasons. A 15-min focal observation was conducted on each subject using the Noldus Observer® program. Abnormal behavior was observed in 26% of the subjects, with motor stereotypy (e.g., pace, rock, swing) being the most common. Motor stereotypy was negatively associated with age when first singly housed (P < 0.005) while self-directed behavior (e.g., hair pull, self-bite) was positively associated with the lifetime number of days singly housed (P < 0.05) and the average number of blood draws per year (P < 0.05). In addition, abnormal appetitive behavior was associated with being male (P < 0.05). Although the baboons in this study exhibited relatively low levels of abnormal behavior, the risk factors for these behaviors (e.g., social restriction, routine veterinary procedures, and sex) appear to remain consistent across primate species.

Inferential reasoning and modality dependent discrimination learning in olive baboons (Papio hamadryas anubis).

Apes use inferential reasoning by exclusion to locate food both in the visual and auditory domain. To test whether olive baboons (Papio hamadryas anubis) show similar abilities as the apes object choice experiments with differing information about food located in 1 of 2 cups were conducted in the visual and auditory modality. Although all baboons (N = 7) were able to locate the reward when they had previously seen it, they failed to make use of auditory cues or arbitrary acoustic signals. When only partial information was given (i.e., only 1 cup was opened) 4 of the baboons were apparently able to infer the location of the reward by reasoning, whereas the other 3 may have adopted an alternative strategy ("avoid the empty cup"). In addition, 3 of the baboons were able to use arbitrary visual markers to locate the food reward. The results suggest that inferential reasoning is not restricted to apes but is shared with Old World monkeys. Furthermore, they also highlight some important differences in the processing of auditory versus visual information in operant conditioning settings.

Testing the function of reconciliation and third-party affiliation for aggressors in hamadryas baboons (Papio hamadryas hamadryas).

In social groups, agonistic conflicts can have different negative consequences. Several post-conflict interactions have been suggested as post-conflict management behaviors to mitigate those negative effects. In this study, we investigated the function of two post-conflict behaviors--reconciliation and aggressor-initiated third-party affiliation--on the aggressor's levels of post-conflict anxiety and aggression in a large colony of hamadryas baboons. We also examined variation in the aggressor's levels of post-conflict anxiety as a function of relationship quality between the opponents as predicted by the Integrated Hypothesis. We found that after conflicts hamadryas baboon aggressors showed increased rates of anxiety-related behaviors and that they were also more likely to be involved in renewed aggressive interactions. Although both reconciliation and aggressor-initiated third-party affiliation reduced the probability of receiving post-conflict aggression, only reconciliation reduced the rates of anxiety-related behaviors, suggesting that the aggressors' post-conflict anxiety might be owing mainly to the damage that the conflict causes to their relationship with the victim. Furthermore, aggressor's rates of post-conflict anxiety were higher after conflicts with individuals with whom they had a high-quality relationship, supporting the idea that levels of post-conflict anxiety mediate the occurrence of reconciliation depending on the quality of the relationship with former opponent as predicted by the Integrated Hypothesis.

Use of social network models to understand play partner choice strategies in three primate species.

Although play is seen in many species, its evolutionary function is still largely unknown. Several relevant, proposed hypotheses (such as the training for the unexpected, self-assessment, social skills, and dominance hierarchy hypotheses) make predictions about how animals should optimally choose their play partners based on their familiarity or other demographic variables. We used a social network approach to analyze focal sample data on brown capuchins (Cebus apella), hamadryas baboons (Papio hamadryas), and diademed sifaka (Propithecus diadema) to understand how these species choose their play partners with respect to demographic variables. Using exponential random graph models (ERGMs), we found that sifaka and capuchins generally tended to play with animals who were similar to them. The baboons were only sensitive to age differences in the formation of strong play relationships. Our data most strongly support the training for the unexpected hypothesis, as according to predictions all species preferred to play with animals who were their close social partners, decreasing the possibility of cheating during play. Through the first application (to our knowledge) of ERGMs to primate behavior, we were able to compare the effects of many demographic variables on the complex, interdependent social structure of primates. Applying this tool to additional groups and species will provide further insight into evolutionary mechanisms of play behavior across taxa.

Kin-mediated reconciliation substitutes for direct reconciliation in female baboons.

It has been hypothesized that group-living mammals engage in reconciliation (post-conflict affiliation between former opponents) to reduce the disruptive costs of aggression and restore opponents' tolerance to baseline levels. Recipients of aggression are sometimes reluctant to tolerate the proximity of a recent opponent, however, in apparent fear that aggression will be renewed. In such cases, reconciliatory behaviour by the aggressor's close kin may substitute for direct reconciliation. We describe a playback experiment with free-ranging baboons (Papio hamadryas ursinus) that examines whether friendly behaviour by the aggressor's kin can substitute for direct reconciliation by the aggressor herself. In the test condition, female subjects who had recently been threatened heard the friendly grunt of one of their aggressor's relatives, mimicking kin-mediated vocal reconciliation. In the control condition, subjects heard the grunt of a dominant female from a different matriline. Subjects responded significantly more strongly in test than in control trials. Moreover, in the next hour they were significantly more likely to tolerate the proximity of both their aggressor and the relative whose grunt they had heard. In contrast, subjects' behaviour towards both control females and other members of their aggressor's matriline was unaffected. We conclude that kin-mediated vocal reconciliation can substitute for direct reconciliation in baboons.

Behavioural and hormonal responses to predation in female chacma baboons (Papio hamadryas ursinus).

In humans, bereavement is associated with an increase in glucocorticoid (GC) levels, though this increase can be mitigated by social support. We examined faecal GC levels and grooming behaviour of free-ranging female baboons to determine whether similar effects were also evident in a non-human species. Females who lost a close relative experienced a significant increase in GC levels in the weeks following their relative's death compared with the weeks before, whereas control females showed no such increase. Despite the fact that females concentrate much of their grooming on close kin, females who lost a close female relative did not experience a decrease in grooming rate and number of grooming partners; instead, both grooming rate and number of grooming partners increased after a relative's death. While the death of a close relative was clearly stressful over the short term, females appeared to compensate for this loss by broadening and strengthening their grooming networks. Perhaps as a result, females' GC levels soon returned to baseline. Even in the presence of familiar troop-mates and other relatives, females experienced a stress response when they lost specific companions, and they apparently sought to alleviate it by broadening and strengthening their social relationships.

Mother-infant relationships in baboons (Papio hamadryas): predictors of differences and discontinuities in developmental pathways.

This study uses hierarchical linear regression modeling to analyze sources of variation in the developmental pathways of mother-infant relationships and to search for behavioral discontinuities. The data come from 23 mother-infant dyads of baboons (Papio hamadryas), whose interactions were recorded longitudinally during the infants' 1st year of life. The infant's sex and the mother's age and reproductive experience accounted for part of the variation observed in the developmental pathways of 11 of 20 behavioral measures analyzed; however, some of them did so only in some periods but not in others. The authors proposed that this can reflect the occurrence of reorganizations or discontinuities in the mother-infant relationship that can be related to important life events such as the mother's resumption of sexual activity.

Does relative economic value of food elicit purposeful encounter in the yellow baboons (Papio hamadryas cynocephalus) of Ruaha National Park, Tanzania?

In the dry season, baboons traveled purposefully to spatially predictable foods that provided a relatively large number of grams per minute of preparation (e.g., economical foods), but not to predictable foods that merely accounted for a large proportion of feeding time (Pochron in Int J Primatol 22:773-785, 2001). In this paper, I examined the generality of those findings across seasons and applied the same methods to baboons eating a lush-season diet. I hypothesized that baboons should travel quickly and directly (i.e., purposefully) only to economical foods. The change in diet brought about by season provided an important comparison. In the lush season, none of the spatially predictable foods provided a relatively large number of grams per minute of preparation, so baboons were predicted to travel purposefully to no lush-season food. In short, baboons who traveled quickly and directly to some foods in the dry season were expected to use indirect and/or slow travel for all lush-season foods. The hypothesis was supported--baboons traveled quickly and directly to no lush-season food. Detailed comparisons between the dry- and lush-season characteristics of baobab fruit show that the food's economic value relative to other foods predicts concurrent fast and direct travel, or the lack thereof, in both seasons.

The Effect of a Feeding Schedule Change and the Provision of Forage Material on Hair Eating in a Group of Captive Baboons (Papio hamadryas sp.).

Hair eating in nonhuman primates is thought to result from a frustrated appetitive drive produced by an inappropriate diet. To investigate whether hair eating could be reduced through changes in diet, a 2-part study was conducted with a group of baboons (Papio hamadryas sp.). The 1st part involved changing to a twice-daily feeding routine, thus providing prolonged access to an appropriate food source. The 2nd part involved scattering a grain mix to encourage more foraging while maintaining a once-daily feeding routine. Changing the feeding routine unexpectedly resulted in a significant increase in hair manipulation and ingestion. Providing additional grain did not significantly decrease hair manipulation and ingestion, but several individuals did show a reduction in these behaviors. Prolonged access to biscuits and the provision of a grain mix may have failed to satisfy the urge to forage because little effort was needed for their collection prior to consumption. Although the current study failed to significantly decrease hair eating, it provides valuable insight into further avenues of research on the behavior.

Inference by exclusion in lion-tailed macaques (Macaca silenus), a hamadryas baboon (Papio hamadryas), capuchins (Sapajus apella), and squirrel monkeys (Saimiri sciureus).

Previous research has suggested that several primate species may be capable of reasoning by exclusion based on the finding that they can locate a hidden object when given information about where the object is not. The present research replicated and extended the literature by testing 2 Old World monkey species, lion-tailed macaques (Macaca silenus) and a hamadryas baboon (Papio hamadryas), and 2 New World species, capuchin monkeys (Sapajus apella) and squirrel monkeys (Saimiri sciureus). The New World monkeys were tested on the traditional 2-way object choice task, and all 4 species were also tested on a more complex 3-way object choice task. In addition, the squirrel monkeys were tested on a 2-way object choice task with auditory information. The results showed that, whereas the Old World species were able to infer by exclusion on the 3-object task, some of the capuchin monkeys had difficulty on each of the 2- and 3-cup tasks. All but 1 of the squirrel monkeys failed to infer successfully, and their strategies appeared to differ between the visual and auditory versions of the task. Taken together, this research suggests that the ability to succeed on this inference task may be present throughout Old World monkey species, but is fragile in the New World species tested thus far. (PsycINFO Database Record

[Redirection and consolation in hamadryas baboons].

Post-conflict interactions between victims and non-involved group members was investigated in the troop of hamadryas baboons, Papio hamadryas. Observations were done in the Russian Primate Center, Adler in 1996-1997. Redirected aggression, initiation of affiliation from the side of victims towards third parties and consolation were registered during this study. The analyses was done on 445 PC-MC pairs of animals, represented different social classes (harem male-female pairs, harem females, relations, females from different harems, male-male pairs, female-subadult pairs). The attracted-pairs method and the time-rule method were used. Redirected aggression was practiced mainly by male aggressees. It was typical for victims, both males and females, to initiate affiliative interactions with third parties soon after the conflict. Consolation was practiced by hamadryas baboons, but it was limited to harem male-female pairs only. Special affiliative patterns were used by male-consoler. This is the first case, when consolation was demonstrated in baboons.

Behavioural processes in social context: female abductions, male herding and female grooming in hamadryas baboons.

The formation of bonds between strangers is an event that occurs routinely in many social animals, including humans, and, as social bonds in general, they affect the individuals' welfare and biological fitness. The present study was motivated by an interest in the behavioural processes that drive bond formation in a social context of hostility, in which the incumbent partners vary greatly in physical power and reproductive interests, a situation in which individuals of many group-living species find themselves often throughout their lives. We focused on the quantitative analysis of female abductions via male aggressive herding in a nonhuman primate, the hamadryas baboon, in which intersexual bonds are known to be strong. We tested three hypotheses informed by sexual conflict/sexual coercion theory (male herding-as-conditioning and female grooming-as-appeasement) and by socioecological theory (unit size and female competition). The results supported the predictions: males resorted to coercive tactics (aggressive herding) with abducted females, and abducted females elevated the amount of grooming directed at their new unit males; in fact, they escaped from the otherwise negative effect of unit size on female-to-male grooming. These findings reveal that conflicts of interest are natural ingredients underpinning social bonds and that resorting to coercive aggression may be an option especially when partners differ greatly in their physical power.

[Reconciliation in hamadryas baboons, Papio hamadryas: testing the relationships quality hypothesis].

Post-conflict interactions between former opponents were investigated in a troop of hamadryas baboons, Papio hamadryas. This species is known for it's multilevel structure with evidently expressed hierarchy between males and females. Due to this fact hamadryas baboons represent an ideal object for testing the "relationship quality" hypothesis. The analyses were done on 436 PC-MC pairs of animals, which represented different social classes (harem male-female pairs, harem females, relatives, females from different harems. Male-male pairs, and female-subadult pairs). Reconciliation was practiced in different social classes of individuals: harem male-female pairs, harem female-female pairs, kin-kin pairs, male-male pairs, female-subadult pairs. Significant differences in the rate of reconciliatory tendency for different categories of interacting animals were found. Interactions between former opponents were highly selective. These may be interpreted as an indicator of the influence of the relation quality on the probability of reconciliation in hamadryas baboons.

Intravenous self-administration of γ-hydroxybutyrate (GHB) in baboons.

BACKGROUND: Abuse of gamma-hydroxybutyrate (GHB) poses a public health concern. In previous studies, intravenous (IV) self-administration of GHB doses up to 10 mg/kg was not maintained in non-human primates under limited-access conditions, which was inconsistent with the usual good correspondence between drugs abused by humans and those self-injected by laboratory animals. METHODS: Self-administration of GHB was studied in 10 baboons using procedures standard for our laboratory to assess drug abuse liability. Each self-injection depended on completion of 120 or 160 lever responses. Sessions ran continuously; a 3-h timeout limited the number of injections per 24h to 8. Self-injection was established at 6-8 injections/day with cocaine (0.32 mg/kg/injection) prior to substitution of each GHB dose (3.2-178 mg/kg/injection) or vehicle for 15 days. Food pellets were available 24h/day. RESULTS: GHB maintained significantly greater numbers of injections when compared to vehicle in 6 of the 9 baboons that completed GHB evaluations that included 32 mg/kg/injection or higher. The baboons that self-administered GHB at high rates were ones for which GHB was the first drug each had tested under the 24-h/day cocaine baseline procedure. Self-injection of the highest doses of GHB decreased food-maintained responding. CONCLUSIONS: High-dose GHB can function as a reinforcer in non-human primates under 24-h access, but self-administration history may be important. The findings are consistent with the demonstrated abuse liability of GHB in humans, and remove GHB as an exception to the typical good correspondence between those drugs abused by humans and those self-administered by nonhuman primates.