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Bshary R, Richter XYL, van Schaik C. Male services during between-group conflict: the 'hired gun' hypothesis revisited. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210150. [PMID: 35369754 DOI: 10.1098/rstb.2021.0150] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
In many group-living mammals, philopatric females form the stable core of the group and defend food or shelter against other groups of females. Where males are larger, their participation could give their female group the edge. How can females secure the contribution of males that are neither the father of current infants, nor the dominant male expecting to sire the next generation of infants? It has been proposed that females recruit these males as 'hired guns', receiving social support and copulations in exchange for fighting, against the interests of the dominant male. We first develop the logic of this hypothesis in unprecedented detail by considering the potential pay-off consequences for females and males. We then provide empirical evidence for the existence of hired guns in this context in several primate species. The game-theoretical aspects of the phenomenon remain to be studied, as is the distribution across contexts (e.g. predation avoidance) and species of the hired gun phenomenon. This article is part of the theme issue 'Intergroup conflict across taxa'.
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Affiliation(s)
- Redouan Bshary
- Behavioural Ecology Laboratory, Faculty of Science, University of Neuchâtel, Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Xiang-Yi Li Richter
- Behavioural Ecology Laboratory, Faculty of Science, University of Neuchâtel, Emile-Argand 11, 2000 Neuchâtel, Switzerland
| | - Carel van Schaik
- Department of Anthropology and Anthropological Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Jordan NR, Buse C, Wilson AM, Golabek KA, Apps PJ, Lowe JC, Van der Weyde LK, Weldon McNutt J. Dynamics of direct inter-pack encounters in endangered African wild dogs. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2338-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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MATSUMOTO-ODA A, PALOMBIT RA. Activity Budgets and Rainfall Seasonality in a Wild Savanna Baboon ( Papio anubis) Group. ACTA ACUST UNITED AC 2015. [DOI: 10.2354/psj.31.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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MARKHAM ACATHERINE, ALBERTS SUSANC, ALTMANN JEANNE. Intergroup conflict: Ecological predictors of winning and consequences of defeat in a wild primate population. Anim Behav 2012; 82:399-403. [PMID: 22837555 PMCID: PMC3402089 DOI: 10.1016/j.anbehav.2012.05.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In many social species, competition between groups is a major factor proximately affecting group-level movement patterns and space use and ultimately shaping the evolution of group living and complex sociality. Here we evaluated the factors influencing group-level dominance among 5 social groups of wild baboons (Papio cynocephalus), in particular focusing on the spatial determinants of dominance and the consequences of defeat. When direct conflict occurred between conspecific baboon groups, the winning group was predicted by differences in the number of adult males in each group and/or groups that had used the areas surrounding the encounter location more intensively than their opponent in the preceding 9 or 12 months. Relative intensity of space use over shorter timescales examined (3 and 6 months) was a poor predictor of the interaction's outcome. Losing groups but not winning groups experienced clear short-term costs. Losing groups used the area surrounding the interaction less following an agonistic encounter (relative to their intensity of use of the area prior to the interaction). These findings offer insight into the influences and consequences of intergroup competition on group-level patterns of space use.
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Affiliation(s)
- A. CATHERINE MARKHAM
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey
| | - SUSAN C. ALBERTS
- Biology Department, Duke University, Durham, North Carolina
- Institute for Primate Research, National Museums of Kenya, Nairobi, Kenya
| | - JEANNE ALTMANN
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey
- Institute for Primate Research, National Museums of Kenya, Nairobi, Kenya
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Bettridge CM, Dunbar R. Predation as a Determinant of Minimum Group Size in Baboons. Folia Primatol (Basel) 2012; 83:332-52. [DOI: 10.1159/000339808] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Bettridge C, Lehmann J, Dunbar R. Trade-offs between time, predation risk and life history, and their implications for biogeography: A systems modelling approach with a primate case study. Ecol Modell 2010. [DOI: 10.1016/j.ecolmodel.2009.11.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Vigilant L, Guschanski K. Using genetics to understand the dynamics of wild primate populations. Primates 2009; 50:105-20. [PMID: 19172380 PMCID: PMC2757609 DOI: 10.1007/s10329-008-0124-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 12/19/2008] [Indexed: 11/09/2022]
Abstract
While much can be learned about primates by means of observation, the slow life history of many primates means that even decades of dedicated effort cannot illuminate long-term evolutionary processes. For example, while the size of a contemporary population can be estimated from field censuses, it is often desirable to know whether a population has been constant or changing in size over a time frame of hundreds or thousands of years. Even the nature of "a population" is open to question, and the extent to which individuals successfully disperse among defined populations is also difficult to estimate by using observational methods alone. Researchers have thus turned to genetic methods to examine the size, structure, and evolutionary histories of primate populations. Many results have been gained by study of sequence variation of maternally inherited mitochondrial DNA, but in recent years researchers have been increasingly focusing on analysis of short, highly variable microsatellite segments in the autosomal genome for a high-resolution view of evolutionary processes involving both sexes. In this review we describe some of the insights thus gained, and discuss the likely impact on this field of new technologies such as high-throughput DNA sequencing.
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Affiliation(s)
- Linda Vigilant
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany.
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Bergman TJ, Kitchen DM. Comparing responses to novel objects in wild baboons (Papio ursinus) and geladas (Theropithecus gelada). Anim Cogn 2008; 12:63-73. [PMID: 18574603 DOI: 10.1007/s10071-008-0171-2] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 03/19/2008] [Accepted: 06/05/2008] [Indexed: 11/30/2022]
Abstract
Behavioral flexibility is considered by some to be one of the hallmarks of advanced cognitive ability. One measure of behavioral flexibility is how subjects respond to novel objects. Despite growing interest in comparative cognition, no comparative research on neophilia in wild primates has been conducted. Here, we compare responses to novel objects in wild chacma baboons (Papio ursinus) and geladas (Theropithecus gelada). Baboons and geladas are closely related taxa, yet they differ in their ecology and degree of social tolerance: (1) baboons are habitat and dietary generalists, whereas geladas have one of the most specialized primate diets (90% grass); (2) baboons exhibit an aversion toward extra-group individuals, whereas geladas typically exhibit an attraction toward them. Using subjects of all age and sex classes, we examined responses to three different objects: a plastic doll, a rubber ball, and a metal can. Overall, baboon subjects exhibited stronger responses to the objects (greater neophilia and exploration) than gelada subjects, yet we found no evidence that the geladas were afraid of the objects. Furthermore, baboons interacted with the objects in the same way they might interact with a potential food item. Responses were unrelated to sex, but immatures showed more object exploration than adults. Results corroborate novel object research conducted in captive populations and suggest that baboons and geladas have differences in behavioral flexibility (at least in this cognitive domain) that have been shaped by ecological (rather than social) differences between the two species.
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Affiliation(s)
- Thore J Bergman
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
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Kunz BK, Linsenmair KE. The Disregarded West: Diet and Behavioural Ecology of Olive Baboons in the Ivory Coast. Folia Primatol (Basel) 2007; 79:31-51. [PMID: 17855793 DOI: 10.1159/000108384] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Accepted: 05/13/2007] [Indexed: 11/19/2022]
Abstract
Despite living under environmental conditions considerably distinct from those of savannah baboons (Papio spp.) in East and southern Africa, very little is known about western Papio populations. We monitored the abundance and group sizes of olive baboons (P. anubis) in the savannah-forest mosaic of the Comoé National Park, northern Ivory Coast, and observed 2 habituated groups of different sizes. Against expectations for the kind of habitat, the individual density was low, yielding only 1.2 baboons/km(2). The groups were small, comprising on average 15 individuals, and the proportion of 1-male groups (50-63%) was remarkably high. One-male groups were more female biased than multi-male groups. The baboons were highly frugivorous, spending about 50% of their feeding time on fruits and seeds of at least 79 woody plant species. The 2 habituated groups had comparatively large home ranges and used forests more often than expected by random. We argue that regular subgrouping of the larger focal group and different habitat quality countervailed inter-group variations. Differences from other study sites, however, are not completely explained by current models of baboon (socio)ecology. It appears that the social organization of olive baboons is more flexible than assumed from data on East African populations.
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Affiliation(s)
- Britta K Kunz
- Department of Animal Ecology and Tropical Biology, Theodor Boveri Institute of Biosciences, University of Wurzburg, Wurzburg, Germany.
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Henzi P, Barrett L. Evolutionary ecology, sexual conflict, and behavioral differentiation among baboon populations. Evol Anthropol 2003. [DOI: 10.1002/evan.10121] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Henzi SP, Lycett JE, Weingrill T. Mate guarding and risk assessment by male mountain baboons during inter-troop encounters. Anim Behav 1998; 55:1421-8. [PMID: 9641987 DOI: 10.1006/anbe.1997.0716] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aggressive herding of females is a frequent but not invariant response by male savannah baboons, Papio cynocephalus, to encounters with other troops. While males in some troops are consistently more likely to herd than those in others, not all inter-troop encounters result in herding, even within particular troops. This suggests that males assess the risk of male invasion posed by each encounter and respond accordingly. We used data from baboon troops in the Drakensberg mountains to determine the rules males follow in deciding whether to herd. Consistent differences between troops were explained only by the adult sex ratio. Males were more likely to herd if the sex ratio of their own troop was female biased, a finding that is concordant with the observation that males are more likely to immigrate into troops where the sex ratio is more female biased than the population average. Differences within troops were a consequence only of encounter distance, with herding being more likely at closer distances. We found a negative correlation between the angle of approach to the other troop and the subsequent angle of deflection. We interpret this to mean that herding functions to increase the distance between the interacting troops, thereby curtailing opportunities for strange males to inspect the troop and determine its sex ratio. In this way, possibly unlike those in other populations, the decision rules of these male baboons are geared to protecting longer-term reproductive prospects. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1997 The Association for the Study of Animal Behaviour.
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Affiliation(s)
- SP Henzi
- Behavioural Ecology Research Group, University of Natal
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Abstract
Data on intergroup-interactions (I-I) were collected in 5 seasonally provisioned groups (A, B, D, D1, and E) of Tibetan macaques (Macaca thibetana) at Mt. Emei in three 70-day periods between 1991 April-June (P1), September-November (P2), December-1992 February (P3). The I-I were categorized as forewarning made by high-ranking males (including Branch Shaking and/or Loud Calls), long-distance interactions in space (specified by changes in their foraging movements), and close encounters (with Affinitive Behavior, Male's Herding Female, Sexual Interaction, Severe Conflict, Adult Male-male Conflict, Opportunistic Advance and Retreat, etc. performed by different age-sex classes). From periods P1 to P3, the I-I rate decreased with reduction in population density as a positive correlate of food clumpedness or the number of potential feeders along a pedestrian trail. On the other hand, from the birth season (BS, represented by P1 and P3) to the mating season (MS, represented by P2) the dominance relation between groups, which produced a winner and a loser in the encounters, became obscure; the proportion of close encounters in the I-I increased; the asymmetry (local groups over intruders) of forewarning signals disappeared; the rate of branch shaking decreased; and sometimes intergroup cohesion appeared. Considering that sexual interactions also occurred between the encountering groups, above changes in intergroup behaviors may be explained with a model of the way in which the competition for food (exclusion) and the sexual attractiveness between opposite sexes were in a dynamic equilibrium among the groups, with the former outweighing the latter in the BS, and conversely in the MS. Females made 93% of severe conflicts, which occurred in 18% of close encounters. Groups fissioned in the recent past shared the same home range, and showed the highest hostility to each other by females. In conspicuous contrast with females' great interest in intergroup food/range competition, adult male-male conflicts that were normally without body contact occurred in 66% of close encounters; high-ranking male herding of females, which is typical in baboons, appeared in 83% of close encounters, and showed no changes with season and sexual weight-dimorphism; peripheral juvenile and subadult males were the main performers of the affinitive behaviors, opportunistic advance and retreat, and guarding at the border. In brief, all males appeared to "sit on the fence" at the border, likely holding out hope of gaining the favor of females both within and outside the group. Thus, females and males attempted to maximize reproductive values in different ways, just as expected by Darwin-Trivers' theory of sexual selection. In addition, group fission was observed in the largest and highest-ranking group for two times (both in the MS) when its size increased to a certain level, and the mother group kept their dominant position in size and rank among the groups that might encounter, suggesting that fission takes a way of discarding the "superfluous part" in order to balance the cost of competition for food and mates within a group, and the benefit of cooperation to access the resources for animals in the mother group.
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Affiliation(s)
- Q K Zhao
- Kunming Institute of Zoology, Chinese Academy of Sciences, Yunnan, People's Republic of China
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Hamilton WJ, Bulger J. Origin and fate of a one-male savanna babbon group formed by fissioning. INT J PRIMATOL 1993. [DOI: 10.1007/bf02196508] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sicotte P. Inter-group encounters and female transfer in mountain gorillas: Influence of group composition on male behavior. Am J Primatol 1993; 30:21-36. [DOI: 10.1002/ajp.1350300103] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/1991] [Accepted: 10/31/1992] [Indexed: 11/05/2022]
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Hamilton WJ, Bulger J. Facultative expression of behavioral differences between one-male and multimale savanna baboon groups. Am J Primatol 1992; 28:61-71. [DOI: 10.1002/ajp.1350280106] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/1991] [Revised: 02/02/1992] [Indexed: 11/09/2022]
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Rhine RJ, Tilson R. Reactions to fear as a proximate factor in the sociospatial organization of baboon progressions. Am J Primatol 1987; 13:119-128. [DOI: 10.1002/ajp.1350130203] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/1986] [Revised: 02/20/1987] [Indexed: 11/06/2022]
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Hamilton WJ. Demographic consequences of a food and water shortage to desert Chacma Baboons,Papio ursinus. INT J PRIMATOL 1985. [DOI: 10.1007/bf02735570] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
The evolution of primate monogamy is described as an ordered sequence of choices by generalized, hypothetical females and males. Females first choose whether or not to associate with other females. Predators encourage gregariousness in diurnal primates; however, nocturnality or scarce and evenly distributed food supplies may enforce separation. A testable group size model based on food patch size is developed and qualitatively supported. If females choose solitude, males then choose either to defend a single female and invest in her offspring, or to compete with other males for access to several females, usually by defending a territory or establishing dominance over the home ranges of several females. The decision rests on the defensibility of females and on the availability of an effective form of male parental investment. Both of these factors are dependent on local female population density. A model is developed that assumes that territorial defense is the principal form of male parental investment, and it predicts that monogamy should occur at intermediate densities: at high densities, males should switch to defense of multiple females, and at low densities there is no investment value in male territorial defense. The model is shown to be only partly adequate. Variation in local population densities prevents the establishment of obligate monogamy through territoriality in small monkeys, since male territorial behavior is inconsistent over the long run. Here, carrying of offspring by males can succeed territoriality, providing an effective and reliable form of parental investment to maintain the pair bond in the face of population fluctuations and changes in group structures. This hypothesis is supported by the scarcity of obligate monogamy among the prosimians, which frequently do not carry their young.
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Dunbar RIM, Sharman M. Female competition for access to males affects birth rate in baboons. Behav Ecol Sociobiol 1983. [DOI: 10.1007/bf00293805] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Territorial behaviour in the green monkey, Cercopithecus sabaeus: Seasonal defense of local food supplies. Behav Ecol Sociobiol 1983. [DOI: 10.1007/bf00296937] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Anderson CM. Levels of social organization and male-female bonding in the genus Papio. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 1983; 60:15-22. [PMID: 6683470 DOI: 10.1002/ajpa.1330600104] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Pair-bonding in the genus Papio seems to be the result of fusion of troops as well as fission. When troop segments regularly split and join again, males who permanently maintain exclusive access to a few females may have an advantage over males who compete for all females who are in estrus. When two or more troops regularly fuse, this advantage may be greatly increased.
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Hamilton WJ, Tilson RL. Solitary male chacma baboons in a desert canyon. Am J Primatol 1982; 2:149-158. [DOI: 10.1002/ajp.1350020203] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/1981] [Accepted: 12/01/1981] [Indexed: 11/08/2022]
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Hamilton WJ. Baboon sleeping site preferences and relationships to primate grouping patterns. Am J Primatol 1982; 3:41-53. [DOI: 10.1002/ajp.1350030104] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/1982] [Accepted: 04/15/1982] [Indexed: 11/09/2022]
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Alternative uses of primates and carnivores in the reconstruction of early hominid behavior. ACTA ACUST UNITED AC 1980. [DOI: 10.1016/0162-3095(80)90002-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Hamilton WJ, Buskirk RE, Buskirk WH. Environmental determinants of object manipulation by chacma baboons (Papio ursinus) in two southern African environments. J Hum Evol 1978. [DOI: 10.1016/s0047-2484(78)80112-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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