TABLE OF CONTENTS
1: Ecological Risk and the Evolution of Great Ape Life Histories - Cheryl D. Knott, Faye S. Harwell
DOI: 10.7208/chicago/9780226728032.003.0001
[life history;ecological risk aversion;development;reproduction;great apes;interbirth interval;menarche]
Primates are characterized as having slow life histories. Great apes exemplify this with relatively longer juvenile periods, later ages at first birth, long interbirth intervals, longer lifespans, and fewer offspring. However, there are significant differences in life history parameters amongst the great apes that have not been adequately explained. This chapter compares infant mortality, age at menarche, age at first reproduction, interbirth interval, age at last birth, and lifespan of the great apes at different long-term field sites and in captivity. These traits display a continuum, with gorillas having the fastest life history, followed by the two Pan species, then orangutans. It is proposed that relative ecological risk, at the genus level, best accounts for these differences. The data presented in this chapter demonstrate that orangutans experience the highest variability in nutritional intake and gorillas the least. Increased ecological risk, specifically starvation, is predicted to result in the selection for a slower life history pattern. A slower life history overall mitigates the effects of ecological risk by distributing energetic demands over longer time periods. Species with the slowest life history, and the greatest ecological risk, also show the greatest phenotypic plasticity when in captivity, where there is lowered ecological risk. (pages 3 - 35)
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2: Growing Up: Comparing Ontogeny of Bonobos and Chimpanzees - Verena Behringer, Jeroen M. G. Stevens, Tobias Deschner, Gottfried Hohmann
DOI: 10.7208/chicago/9780226728032.003.0002
[Pan paniscus;Pan troglodytes;development;physiological monitoring;life history;hormones]
Bonobos and chimpanzees share developmental traits such as slow somatic growth, a long period of nutritional dependency, and a late onset of reproduction. However, there is also evidence for differences in the timing of somatic, social, and cognitive development. This chapter assesses the extent of heterochrony across developmental trajectories by comparing physiological markers affecting somatic growth, adrenarche, puberty, and metabolism. This study includes markers such as thyroid hormones and insulin-like growth factor-binding protein, which are indicative of somatic growth during the period between birth and puberty, as well as markers that relate to the induction and onset of reproductive maturation. Results are derived from cross-sectional and longitudinal analyses of records from captive individuals representing a large number of groups that differ in size, demography, and genetic constitution. Although the results support the notion that development of the two species is heterochronic, they reveal a differentiated picture with bonobos being delayed in terms of somatic growth and chimpanzees being delayed in female sexual maturation. The temporal differences of development and maturation indicate species-differences in life history strategies. Long-term monitoring of development and maturation will provide the context for traits separating humans and primates as well as those that we share. (pages 36 - 60)
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3: Dolphins and Chimpanzees: A Case for Convergence? - Janet Mann, Margaret A. Stanton, Carson M. Murray
DOI: 10.7208/chicago/9780226728032.003.0003
[cetaceans;social development;maternal behavior;fission-fusion;foraging ecology;life history;sex-differences;alliances]
Although convergence in dolphins and chimpanzees has been noted for decades, a lag in life history and behavioral data for bottlenose dolphins long precluded direct comparisons. As several long-term studies of bottlenose dolphins have reached a mature stage, such comparisons are now feasible. Evidence for convergence includes similarly extended life histories, with prolonged development and societies characterized by multi-male, multi-female groups, sex-segregation, promiscuous mating, alliance formation, and high fission-fusion dynamics. However, the distinct ecologies of these species drives critical differences. Compared to the closed communities of terrestrial chimpanzees, dolphins in their marine environment tend to show larger, open communities with more fluid subgroups. Additionally, despite similar age at weaning and sexual maturity, physically precocious dolphin calves show greater independence than their chimpanzee counterparts both before and after weaning. Notably, chimpanzees are also typically male philopatric, while most bottlenose dolphin societies are bisexually philopatric. As a likely result, female kinship bonds are stronger than male kinship bonds in dolphins, while the reverse is often true in chimpanzees. This chapter discusses these patterns in an effort to facilitate dialogue between researchers of these intriguingly long-lived, large-brained, and socially complex taxa. (pages 61 - 92)
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4: Social Behavior and Social Tolerance in Chimpanzees and Bonobos - Jared P. Taglialatela, Sara A. Skiba, Robert E. Evans, Stephanie L. Bogart, Natalie G. Schwob
DOI: 10.7208/chicago/9780226728032.003.0004
[social behavior;communication;tolerance;chimpanzees;bonobos;evolution]
Studying similarities and differences in socio-communicative behavior between chimpanzees and bonobos is critical to our understanding of the evolution of human sociality and communication. Despite their shared phylogeny and comparable morphology, the two species exhibit notable differences in socio-communicative behavior. Similarities in feeding ecology likely played a crucial role in selecting for the advanced cognitive abilities of both species. However, differences in feeding ecology may have also led to divergence in socio-communicative behavior. This chapter reviews the literature comparing chimpanzee and bonobo sociality in both captive and field settings and presents data comparing chimpanzee and bonobo social behavior in captive settings. These data indicate that bonobos in captivity are more likely to be in direct physical proximity of group members and spend more time grooming than chimpanzees. In addition, experimental data indicate chimpanzees are in closer proximity to conspecifics during social foraging tasks and share food more often than bonobos. These results suggest that while bonobos may be more social than chimpanzees, chimpanzees may be more socially tolerant during feeding. Further study of the differences in the socio-communicative behavior of the two species most closely related to humans will continue to provide invaluable insight into our own evolution. (pages 95 - 114)
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5: Endurance and Flexibility of Close Social Relationships: Comparing Chimpanzees (Pan troglodytes verus) and Sooty Mangabeys (Cercocebus atys atys) - Roman M. Wittig, Alexander Mielke, Jack Lester, Catherine Crockford
DOI: 10.7208/chicago/9780226728032.003.0005
[sociality;bonds;mangabey;behavioral flexibility;kin relationship;non-kin relationship;social structure;Dynamic Dyadic Sociality Index;chimpanzee]
Many social animals form enduring and close social relationships that have positive effects on fitness. Most species form close social relationships between maternal kin, which makes them enduring, but inflexible. Some species, however, also form close social relationships among unrelated individuals. These relationships are subject to changes when benefits of the relationship change. Endurance and flexibility of close social relationships, however, are rarely directly compared across species using the same method. This chapter compares social relationships of male-philopatric chimpanzees and sympatric, female philopatric sooty mangabeys. This chapter explores how many close social relationships are formed between kin and non-kin partners, how enduring these relationships are, and how flexible the relationship quality of these dyads is using a dynamic sociality index. This chapter reveals that mangabeys form bonds primarily with females and, when possible, with maternal kin. Chimpanzees, in contrast, chose bond partners of both sexes and do not prefer maternal kin over others. Thus, mangabey bonds are more enduring and less flexible compared to chimpanzee bonds. Bond endurance and flexibility are features differing between matrilineal species with despotic dominance structure and species with more egalitarian structures, possibly affecting social cognition and complexity. (pages 115 - 136)
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6: Urinary Androgens, Dominance Hierarchies, and Social Group Structure among Wild Male Mountain Gorillas - Stacy Rosenbaum, Rachel Santymire, Tara S. Stoinski
DOI: 10.7208/chicago/9780226728032.003.0006
[testosterone;intrasexual competition;challenge hypothesis;great ape;rank;social relationships;enzyme immunoassay;radioimmunoassay;Gorilla beringei]
In many species androgens (e.g. testosterone) play an important role in male-male competition, mediating both intra- and inter-group competitive relationships. The connection between competition and androgens has been relatively well-studied in the genus Pan, but less so in other great apes. This chapter examines the relationship between urinary androgen metabolites (UAM) and dominance rank, as well as social group structure, in wild male mountain gorillas (Gorilla beringei). Data from two different time periods indicate there is no clear relationship between UAM and rank in this species. Instead, they suggest that any such connection might be mediated by the social dynamics among group members, including dominance hierarchy stability and/or the security of the dominant male’s tenure. There was also no clear relationship between UAM concentrations and social group structure. Males in multi- and single-male groups had similar concentrations, though very preliminary data suggest that solitary males might have lower UAM levels than their group-dwelling peers. Thus, there is weak support for the hypothesis that male mountain gorillas’ intrasexual competition is mediated by baseline androgen levels. They may therefore have more in common with bonobos (Pan paniscus) than chimpanzees (P. troglodytes) on this dimension, despite their extreme adaptations for male-male contest competition. (pages 137 - 164)
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7: Methods to Study Chimpanzee Social Learning from a Comparative Perspective - Lydia M. Hopper, Alecia J. Carter
DOI: 10.7208/chicago/9780226728032.003.0007
[social learning;monkey;ape;field research;comparative methods;comparative cognition]
Social learning describes how one individual can gain information or learn a new skill from observing the actions of another, or the outcomes of their actions. Social learning can potentially enable individuals to avoid time-consuming or even potentially lethal individual learning as they can learn from the success and failures of others. However, the efficacy and usefulness of socially-provided information varies, and so when an individual should copy others, and who they should copy, is a delicate balance. Interest in primate social learning has gained momentum in recent decades, most likely predicated by reports of cultural variation between wild groups of chimpanzees and other primates that have been suggested to rely on social learning. This chapter describes the approaches taken to study primate social learning, as well as the advantages and limitations of each, with a particular aim to review both observational and experimental approaches, and also studies with captive and wild populations. This chapter provides an overview of the sometimes seemingly disparate techniques used to study primate social learning in order to recommend practices typically restricted for use in one setting or species that could be translated to other settings to provide insights about chimpanzee social learning. (pages 167 - 188)
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8: Automated Methods and the Technological Context of Chimpanzee Research - Christopher Flynn, Ikuma Adachi
DOI: 10.7208/chicago/9780226728032.003.0008
[automated methods;cognition;research methods;touchscreen;history of psychology;enrichment;animal computer interaction;animal technology]
The use of automated methods in chimpanzee psychology research has a long history, from early behaviorism techniques involving levers and lights to modern-day cognitive studies using computerized touch-panel tasks. The technology behind these efforts has contributed to a deeper understanding of the chimpanzee mind by providing researchers with robust empirical platforms that highlight objectivity, precision, and detailed recordkeeping. This chapter gives an historical overview of the advancement of automated methods and their use-cases, each of which is characterized by the technology of the era, the context in which it was used, and the principal questions guiding the research. Expanded focus is given to the introduction and adoption of the computerized touch-panel task paradigm and its contribution to studies on chimpanzee memory, psychophysics, and natural cognition undertaken by the Ai Project of Kyoto University. The growing trend of utilizing computerized tasks for great ape welfare and enrichment purposes is also discussed, as are the recent efforts to expand the usage of automated tasks in zoo settings. (pages 189 - 207)
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9: The Establishment of Sanctuaries for Former Laboratory Chimpanzees: Challenges, Successes, and Cross-Cultural Context - Satoshi Hirata, Naruki Morimura, Koshiro Watanuki, Stephen R. Ross
DOI: 10.7208/chicago/9780226728032.003.0009
[sanctuaries;Japan;laboratory;welfare;policy;zoo;chimpanzee]
The United States and Japan are the two countries holding highest number of captive chimpanzees in the world. These countries were also most involved in past biomedical experimentation on this species, leading to their subsequent retirement to sanctuaries. This chapter describes the history of captive chimpanzees in Japan and the United States and provides a parallel perspective on the establishment of sanctuaries in these two countries. There are commonalities, such as a seismic shift in sentiment about the use of chimpanzees in invasive medical research followed by widespread retirement efforts, and differences, such as cultural context of how sanctuaries are supported and managed, with or without involvements from government and private sector, with respect to the history of chimpanzee sanctuaries in these countries. The establishment of chimpanzee sanctuaries is a relatively recent event globally, and thus opportunities remain to pursue partnerships with other organizations that can provide specialized expertise. To date, there has been relatively little substantive communication or collaboration between sanctuaries in Japan, the United States, and around the world. As populations of chimpanzees in sanctuaries continue to rise, global collaboration of these facilities in different countries has the potential to greatly benefit the care of this species. (pages 208 - 230)
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10: Gestural Communication in the Great Apes: Tracing the Origins of Language - Catherine Hobaiter
DOI: 10.7208/chicago/9780226728032.003.0010
[gesture;communication;intentional;language;meaning;chimpanzee]
Exploring the evolutionary origins of language presents a significant challenge: signals across species do not fossilize. Nevertheless, no other single capacity better defines what is apparently unique about the human species. The signals of modern primate species have been shown to encode rich information, but meaning in human language has been treated differently; taking into account not only the structure of the signal but also the intention of the signaller. Today, a diverse body of evidence suggests that chimpanzees and bonobos share our capacity for intentional goal-directed communication, particularly in their large repertoires of gestures. From this starting point we can begin to explore what other features of language-like communication they share. To do so we must do more than describe a check-list of features, we must also explore how they use their gestures. Importantly in order to describe meaningful differences and similarities between ape gesture and human language, we must describe gestural communication from the perspective of the ape species using it. (pages 233 - 259)
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11: Flexibility in Great Ape Vocal Production - Simon W. Townsend, Stuart K. Watson, Katie E. Slocombe
DOI: 10.7208/chicago/9780226728032.003.0011
[vocal communication;vocal flexibility;monkeys;apes;language evolution;communication]
Language’s emergence has been argued to represent one of the major evolutionary transitions in the history of life, yet elucidating its origins is challenging. However, unpacking the phylogenetic roots of language through studying non-human primate communication can shed light on the evolution of key linguistic features. Despite accumulating a wealth of data on primate referential capabilities, less attention has focused on the psychological mechanisms underlying primate vocal production. Several previous reviews of monkey neural and behavioral data have concluded that monkey vocal production is not under voluntary or cortical control, and extrapolation of these findings to apes has led to the assumption that vocal production in our closest-living relatives is inflexible, hardwired and qualitatively different to human language. This chapter presents recent developments in vocal research that begin to challenge these traditional assumptions. Specifically, this chapter describes recent behavioral and neurobiological evidence that suggests monkeys demonstrate greater flexible control over vocal production than previously thought. Furthermore, in light of observational and experimental data in chimpanzees and other apes, this chapter argues that inferences about vocal flexibility in apes based on monkey data should be made with caution. (pages 260 - 280)
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12: Vocal Communication in Chimpanzees and Bonobos: A Window into the Social World - Zanna Clay
DOI: 10.7208/chicago/9780226728032.003.0012
[great apes;vocalizations;language evolution;social cognition;vocal flexibility;sociality;communication]
Investigating how animals produce and understand vocalizations can provide a useful window through which to explore the underlying social awareness driving their communication. It can also provide insights into the similarities and differences shaping the behavior of closely related species. Despite being closely related and showing many similarities, research highlights some striking differences between chimpanzees (Pan troglodytes) and their close sister species, the bonobos (P. paniscus). This chapter reviews recent research and explores what vocal communication can tell us about these species’ social worlds. In this chapter, chimpanzee and bonobo vocal expressions of social dominance and socio-reproductive strategies are compared as well as the role that vocalizations play in travel and coordination between groups. Research highlights considerable degrees of social awareness, with evidence that both species can produce vocalizations in socially-directed, flexible and intentional ways to pursue different social, ecological and reproductive strategies. Given the equally close genetic relationship that chimpanzees and bonobos share with humans, comparing their communicative behaviors enables a more balanced and nuanced picture of what our own species might have looked like before we became human. (pages 281 - 302)
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13: Cooperation and Communication in Great Apes - Shona Duguid, Matthias Allritz, Africa De Las Heras, Suska Nolte, Josep Call
DOI: 10.7208/chicago/9780226728032.003.0013
[communication;cooperation;coordination;collaboration;loose string task;helping;prosocial behavior;gestures;tool transfer]
The experimental study of cooperation in nonhuman primates can be traced back to Crawford’s seminal work with captive chimpanzees in the 1930s and 1940s. He described how pairs of chimpanzees pull together a heavy box to obtain food, and even reported communicative acts between cooperating partners. Although multiple studies since then have documented pairs of individuals coordinating their actions to achieve a common goal, communicative exchanges between partners are not frequent and often failed to fix situations when coordination is failing. This chapter discusses whether this lack of communication is a methodological artifact or whether there is a deeper theoretical reason underlying this observation. This chapter opens with a review of the literature on experimental studies on cooperation, paying particular attention to the occurrence of communicative exchanges between partners. Second, the chapter describes three recent experiments using three different coordination tasks. This chapter stresses the importance of variation in experimental task design to better understand the motivational and cognitive processes underlying the interplay between cooperation and communication in the great apes. (pages 305 - 329)
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14: The Evolution of Cooperation in Dyads and in Groups: Comparing Chimpanzees and Bonobos in the Wild and in the Laboratory - Shinya Yamamoto
DOI: 10.7208/chicago/9780226728032.003.0014
[cooperation;chimpanzees;helping;sharing;tolerance;bonobos;comparative research;field research]
Cooperation may be a human hallmark, but its evolutionary basis can be found in both chimpanzees and bonobos. This chapter discusses the evolution of cooperation by comparing data from chimpanzees and bonobos both in the wild and in captivity. Much research has previously focused on dyadic cooperation, such as sharing, helping, and reciprocity between two individuals. These studies have revealed that chimpanzees are reluctant to help proactively, even though they have the cognitive ability to understand others’ desires. Bonobos appear to be somewhat different from chimpanzees. They are more spontaneous, tolerant of others, and, like humans, better at collaborative activities. Such comparisons of dyadic cooperation between chimpanzees and bonobos may lead to the hypothesis that cooperative society has evolved primarily in stable environments with large food patches (i.e. “rich” environments) like those in which most bonobos inhabit. However, in the context of group cooperation, wherein chimpanzees sometimes outperform bonobos, a different perspective may lead to the hypothesis that group cooperation evolved predominantly in “poor” environments where animals had to collaborate in groups to find resources and to protect themselves against out-group threats. (pages 330 - 345)
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15: Putting Chimpanzee Cooperation in Context - Gillian L. Vale, Sarah F. Brosnan
DOI: 10.7208/chicago/9780226728032.003.0015
[anti-coordination;assurance game;cooperation;coordination;decision making;experimental economics;hawk-dove game]
Cooperation plays a fundamental role in the success of our species. Although other species also cooperate, they do not reach the same degree of complexity or achieve the same levels of coordinated action as humans do. Why cooperation evolved to varying extents in different species remains one of the big questions for science. One way in which we can study this is to focus upon the phylogeny of cooperation and the mechanisms that underpin it. This chapter focuses on the degree to which nonhuman primates (hereafter primates) are similar or dissimilar in their tendency to cooperate, especially as compared to chimpanzees. This chapter outlines the findings from a large-scale comparative project that has compared primates using carefully standardized tasks adapted from experimental economics. The results suggest that in some cases, primates find the Nash Equilibria on these tasks. Nonetheless, decisions also differ in important ways, from each other’s and from humans’, and these differences are informative for understanding the evolution of these decision patterns. This chapter concludes by considering what the results mean for our understanding of chimpanzee behavior and cognition. (pages 346 - 367)
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16: A Comparison of Cooperative Cognition in Corvids, Chimpanzees, and Other Animals - Jorg J. M. Massen, Wouter A. A. Schaake, Thomas Bugnyar
DOI: 10.7208/chicago/9780226728032.003.0016
[ravens;social cognition;convergent evolution;experimental procedures;knowledge probes;experience;coordination]
Over the last decade, comparative work on animal cooperative problem solving has gained considerable momentum. Specifically, several primates, social carnivores, elephants, and some parrots and corvids have now been shown to master the cooperative ‘loose-string’ paradigm in which two individuals must simultaneously pull a string to obtain rewards. However, results are inconsistent. While this variance is often interpreted as highlighting differences in cognitive skills between species, alternatively they may reflect differences in the procedure used or training and experience. This chapter presents a series of experiments that investigated the influence of experience with ravens, Corvus corax, that already spontaneously solved the loose-string paradigm, but originally failed knowledge probes. These studies examined whether, after gaining additional experience, birds understood the need of a partner and the need for coordination with that partner. The results revealed that, given sufficient experience, ravens managed to better coordinate their actions and successfully solve the paradigm. This chapter discusses these results in comparison with chimpanzees and other animals tested in similar paradigms and highlights the importance of methodological design for comparative research. This chapter concludes by proposing a more critical framework for the interpretation of results of cooperation experiments and their related knowledge probes. (pages 368 - 388)
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17: Extractive Foraging in an Extreme Environment: Tool and Proto-tool Use by Chimpanzees at Fongoli, Senegal - Jill D. Pruetz, Stephanie L. Bogart, Stacy Lindshield
DOI: 10.7208/chicago/9780226728032.003.0017
[savanna chimpanzees;tool use;proto-tool;extractive foraging;opportunity hypothesis;necessity hypotheses;tool-assisted hunting;termite fishing;baobab cracking]
Fongoli chimpanzees appear to rely on tool use to successfully combat the pressures they face in the savanna-woodland mosaic of southeastern Senegal. This chapter provides information on these apes’ extractive foraging behavior collected between 2006-2016. While the Fongoli tool kit varies less than that of some forest-living communities, tool behavior is frequent and could be instrumental for their survival in this harsh environment. This chapter focuses on tool and proto-tool use involving two top foods (Macrotermes termites and baobab fruit [Adansonia digitata]), as well as the unique tool-assisted hunting behavior on Galago senegalensis. The opportunity and necessity hypotheses are both examined to explain these behaviors. Based on phenological data, scarcity of ripe fruit at Fongoli does not explain tool-assisted hunting or termite-fishing behavior, thus providing stronger support for the opportunity hypothesis. Tool-assisted hunting behavior is concentrated in the early rainy season and termite fishing predominantly occurs in the late dry and early wet seasons when fruit availability is high. Finally, Fongoli chimpanzees use proto-tools, stone or wood anvils, to crack open baobab fruits when seasonally abundant, which lends support to the necessity hypothesis. These findings are compared to data from forest-dwelling chimpanzees to provide further perspective on chimpanzee behavioral ecology. (pages 391 - 409)
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18: Cultural Transmission in Dispersing Primates - Lydia V. Luncz, Erica Van De
DOI: 10.7208/chicago/9780226728032.003.0018
[cross-species comparisons;conformity;culture;dispersal;vervet monkeys;chimpanzees;field experiments;observational data;tool use]
The study of culture in wild animals has received increasing attention of researchers from different disciplines and has evolved from studying differences across groups to identifying underlying learning mechanisms involved in creating stable diversity across animal populations. Immigration in animals has been proven to be an interesting phenomenon where information on adaptation to local group norms can be directly observed. This chapter compares the behavior of wild primates during migration events, with a focus on observational data in wild chimpanzees from the Taï National Park in Côte d’Ivoire and field experiments in vervet monkeys from the Inkawu Vervet Project in South Africa. These cross-species comparisons reveal that both primate species show conformist behavior mechanisms, where they abandon the knowledge that they previously had learned in their native group before dispersal and adopt the behavior displayed throughout their new group. This chapter argues that other animal species, beyond the primate lineage, show similar social learning phenomena when dispersing, highlighting the possibility that migration events trigger conformity throughout the animal kingdom. (pages 410 - 427)
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19: On the Origin of Cumulative Culture: Consideration of the Role of Copying in Culture-Dependent Traits and a Reappraisal of the Zone of Latent Solutions Hypothesis - Claudio Tennie, Lydia M. Hopper, Carel P. Van Schaik
DOI: 10.7208/chicago/9780226728032.003.0019
[culture;tool use;zone of latent solutions;culture-dependent traits;social learning;observational learning;copying;cumulative culture;chimpanzee;great apes]
An understanding of ape culture offers important insights into the evolution of human culture. This chapter presents the argument that ape tool cultures consist of socially-mediated branching chains of individually-derived behaviors (‘latent solutions’) and presents the hypothesis that the evolved motivations and skills of apes potentially enable them to individually create all tool behaviors shown by any other conspecific. Through non-copying observational learning mechanisms, each individual becomes sufficiently likely to express the latent solution variants shown in their group. But even with social mediation, each chimpanzee still must generate the underlying behavior individually (i.e. reinnovate it). Ultimately, reinnovation arises due to an interplay between environmental factors, motivation and skill. While the resulting uniformity of behavior within chimpanzee groups can create the illusion that their culture requires copying, we review the evidence and conclude this is not the case. Furthermore, latent solutions are not limited to chimpanzees – they may underlie the cultures of many other animals, and presumably those of earlier hominins. While our own species also possesses a ‘zone of latent solutions,’ the additional behaviors and technology that we use and produce today cannot occur unless they are culturally transmitted: they are not only cumulative, but truly culture-dependent traits. (pages 428 - 453)
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20: Cognitive Control and Metacognition in Chimpanzees - Michael J. Beran, Bonnie M. Perdue, Audrey E. Parrish
DOI: 10.7208/chicago/9780226728032.003.0020
[chimpanzees;metacognition;confidence;cognitive control;consciousness;perception]
Cognitive control involves a number of executive and regulatory processes. It is a hallmark feature of human cognition, and recent comparative tests have shown that some nonhuman animals might share aspects of cognitive control with humans. One such aspect is metacognition: “thinking about thinking.” Metacognition allows individuals to assess what information they have and what information they still need, and it provides measures of confidence in knowledge and ability.It has been shown that chimpanzees show confidence in responses to cognitive tests by moving to a reward dispenser more often when they were correct than when they were incorrect, and without waiting for external feedback as a cue to whether they should move to the dispenser or not.This chapter presents new data that indicate how one chimpanzee extended these ‘confidence movements’ to new tasks that assessed quantitative abilities and perceptual acuity. These demonstrations may reflect certain types of metacognitive capacities in chimpanzees that approximate those of humans, and the performances of chimpanzees in these kinds of tests have implications for considering the nature of the intelligence of these animals and perhaps implications regarding states of conscious awareness in chimpanzees. (pages 454 - 478)
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21: Chimpanzees in US Zoos, Sanctuaries, and Research Facilities: A Survey-Based Comparison of Atypical Behaviors - Mollie A. Boomsmith, Andrea W. Clay, Stephen R. Ross, Susan P. Lambeth, Corrine K. Lutz, Sarah D. Breaux, Rhonda Pietsch, Amy Fultz, Michael L. Lammey, Sarah L. Jacobson, Jaine E. Perlman
DOI: 10.7208/chicago/9780226728032.003.0021
[animal management;animal welfare;behavioral management;early rearing effects;behavior;great ape;psychological well-being;stereotyped behavior]
The scientific study of chimpanzee welfare has long included the evaluation of atypical or abnormal behavior as one category of well-being measures. This chapter examines the characteristics of chimpanzees performing abnormal behaviors and describes a very large and diverse sample of individuals living in three different captive settings (research facilities, zoos and sanctuaries in the United States). Specifically, this chapter presents the results of a study that used a written survey to characterize the prevalence of seven types of abnormal behaviors in relation to the facility type, early rearing, group size, sex, and age of chimpanzees. The results of this study revealed that the profile of abnormal behavior prevalence varies across the settings in which chimpanzees currently live, and that age, sex, early rearing history and current social group size are also associated with the prevalence of some abnormal behaviors. Furthermore, each type of abnormal behavior correlates with multiple factors, highlighting the complex etiology of chimpanzee abnormal behavior. Truly understanding the welfare of an individual chimpanzee must include assessing the animal’s history and the current circumstances, both of which impact the animal’s present behavior. (pages 481 - 508)
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22: When Is “Natural” Better? The Welfare Implications of Limiting Reproduction in Captive Chimpanzees - Katherine A. Cronin, Stephen R. Ross
DOI: 10.7208/chicago/9780226728032.003.0022
[animal welfare;breeding;chimpanzees;reproduction;abnormal behavior;zoo]
Minimizing the mismatch between wild conditions and captive conditions is widely thought to be a powerful strategy to promote positive animal welfare. This chapter explores the potential relationships between “natural” environments and animal welfare in theory, and then focuses on whether creating an “unnatural” environment, by limiting reproduction in chimpanzees, has a measurable impact on one behavioral indicator of welfare. Of interest was whether the presence or absence of young chimpanzees in social groups was associated with differences in the prevalence of abnormal behaviors. Survey data for 207 individuals living in 26 different accredited facilities was used to assess the prevalence of abnormal behaviors and were analyzed using generalized linear mixed models that also considered origin, sex and rearing. Results indicated that the presence of young was not predictive of abnormal behavior in this population. When considered alongside the results of a previous study of sanctuary-housed chimpanzees, there seems no clear behavioral evidence to suggest that the presence of young in a social group is associated with better animal welfare. This discussion of the value of “natural” and “unnatural” environments will hopefully spark additional research into the complex question of how managing reproduction impacts the welfare of captive chimpanzees. (pages 509 - 523)
This chapter is available at:
University of Chicago Press
https://academic.oup.com/chica...
23: How Chimpanzee Personality and Video Studies Can Inform Management and Care of the Species: A Case Study - Elizabeth S. Herrelko, Sarah-Jane Vick, Hannah M. Buchanan-Smith
DOI: 10.7208/chicago/9780226728032.003.0023
[chimpanzee;zoo;introductions;animal management;personality;video;sociality;dominance;behavior;animal welfare]
When caring for socially-housed animals such as chimpanzees, zoos carefully plan group compositions, and assess the need for animal transfers, to maintain genetic diversity of captive populations and provide naturalistic groups. Introducing chimpanzees to new social groups can be difficult, with little empirical evidence to guide the process. This chapter presents a case study to illustrate the intricacies of the process and evaluate the usefulness of video footage and personality ratings to aid the process. It was tested whether personality measures and behaviors observed during video introductions and a visual-access period predicted the outcomes of social introductions between two chimpanzee social groups. Chimpanzees’ high scores on the personality trait Dominance predicted aggression (to all others, outgroup individuals, and males); high Conscientiousness predicted neutral interactions (when meeting males, higher ranked individuals, and both in-group and out-group individuals); but personality ratings did not predict affiliative outcomes. Affiliative or aggressive behavioral responses to video footage did not predict congruently-valenced responses during physical introductions. Behavioral responses during the visual access period also did not predict any affiliative, aggressive, or neutral outcomes. This case study suggests that personality measures, with continued refinement, have considerable potential as a tool in captive animal management. (pages 524 - 551)
This chapter is available at:
University of Chicago Press
https://academic.oup.com/chica...
24: Chimpanzee Welfare in the Context of Science, Policy, and Practice - Stephen R. Ross
DOI: 10.7208/chicago/9780226728032.003.0024
[chimpanzee;welfare;wellbeing;enrichment;captive care;husbandry;animal management]
For chimpanzees, a species renowned for their intellect, problem-solving abilities and emotional complexity, the task of comprehensively reviewing what is known about their psychological welfare is daunting but overdue. Unlike past efforts which have focused on using what is known about wild chimpanzees, this chapter focuses instead on what has already been revealed through studies of captive chimpanzees in order to further progress their care and management. Following on expert opinion about what is most important for improvement of chimpanzee welfare, the information is organized into considerations of a chimpanzee’s social life, physical environment, opportunities for choice and control, relationships with humans, enrichment, and nutrition. Each section also incorporates regulatory and management information with which the scientific literature can be provided appropriate practical context. Finally, there is an overt encouragement for managers to take a “bias for action” approach to the implementation of the extant research presented here; advocating for policy and management progress even as additional quantitative evidence continues to be collected. (pages 552 - 582)
This chapter is available at:
University of Chicago Press
https://academic.oup.com/chica...
25: Chimpanzee Conservation: What We Know, What We Do Not Know, and Ways Forward - Colin A. Chapman, Kim Valenta, Sarah Bortolamiol, Sam K. Mugume, Meng Yao
DOI: 10.7208/chicago/9780226728032.003.0025
[conservation;deforestation;primate disease;conservation education;bushmeat;African development]
The world is changing rapidly and its biodiversity is being lost. It is estimated that close to 50% of the world’s primates are at risk of extinction, with 14.5% critically endangered. Chimpanzees (Pan troglodytes) are one of these endangered species and because of their iconic status and phylogenetic closeness to humans, they are a special endangered species. It is estimated that chimpanzee populations have experienced significant declines in the past 20 to 30 years and overall the population reduction over three-generations is estimated to exceed 50%. This chapter documents the current threats to chimpanzee to illustrate what the scientific and conservation communities know and do not know and illustrate the way forward. The relative contributions of deforestation, the bushmeat industry, disease, and climate change as factors driving chimpanzee population declines are considered. While the situation is grim, there are a number of promising actions that can be taken; improved law enforcement, reduced impact logging, reforestation associated with carbon storage and efforts to mitigate climate change, education and public outreach, and new emerging models for conservation funding. Chimpanzees are our closest living relatives and are wonderful intelligent animals; they deserve to be treated much better than humans are treating them now. (pages 585 - 611)
This chapter is available at:
University of Chicago Press
https://academic.oup.com/chica...
26: Holistic Approach for Conservation of Chimpanzees in Kibale National Park, Uganda - Jessica A. Hartel, Emily Otali, Zarin Machanda, Richard W. Wrangham, Elizabeth Ross
DOI: 10.7208/chicago/9780226728032.003.0026
[chimpanzee;Pan troglodytes;conservation;education;snare;poaching;conservation education]
Uganda’s Kibale National Park contains a diverse primate population, including about 1400 chimpanzees. It is threatened by poaching and illegal deforestation, both of which are promoted by the extreme poverty, exponential population growth, and limited educational opportunities of local people. This chapter describes the Kibale Chimpanzee Project’s multifaceted approach to conservation in this region since 1997, which includes on-the-ground conservation efforts within the park, paired with community outreach and development outside the park to address persistent and evolving human-chimpanzee conflict issues. In the last two decades, Kibale Snare Removal Project (KSRP) rangers have deployed more than 5000 park patrols and removed over 8500 snares, leading to a decline in both the frequency of snare-related chimpanzee injuries and the rate of deforestation at Kanyawara. Concurrently, the Kasiisi Project implemented conservation-based activities in 16 local schools located within 5 km of the park’s boundary. As participation in these activities increased, the project documented positive attitudinal and behavioral shifts in students’, teachers’, and parents’ views of chimpanzees, other wildlife, and the environment. The collaboration between these two projects has shown that long-term chimpanzee conservation can be enhanced by active on-the-ground conservation measures paired with a well-educated population with good environmental knowledge. (pages 612 - 643)
This chapter is available at:
University of Chicago Press
https://academic.oup.com/chica...
27: Forest Certification and the High Conservation Value Concept: Protecting Great Apes in the Sangha Trinational Landscape in an Era of Industrial Logging - David B. Morgan, William Winston, Crepin Eyana Ayina, Wen Mayoukou, Eric V. Lonsdorf, Crickette M. Sanz
DOI: 10.7208/chicago/9780226728032.003.0027
[selective logging;forestry;great apes;monitoring;habitat suitability;conservation]
Surveys in certified logging concessions across Congo Basin indicate that Forest Stewardship Council (FSC) certification processes have produced positive results benefiting wildlife in the context of timber exploitation. Even so, assessment of the costs and benefits accrued from certification necessitates a long-term approach. Great apes such as chimpanzee and gorilla responses to logging and environmental change are complex. There is valid concern that the consequences associated with exploitation of pristine forest could have negative long-term consequences. As part of a landscape monitoring program the authors of this chapter inventoried the loss of Intact Forest Landscape (IFL) and associated deforestation from 2013 to 2017 in seven logging concessions neighboring the Sangha Trinational landscape, a World Heritage Site in central Africa. To better understand the availability of ape resources, species specific habitat suitability were modeled across the protected area network. A chimpanzee-to-gorilla habitat gradient was found, with the western parks protecting relatively more gorillas while the eastern parks protect more chimpanzees. These results are used to address the debate surrounding the impact of logging in IFL. Findings are also linked to the High Conservation Value Forest concept to provide guidance on defining important attributes and core areas of conservation. (pages 644 - 670)
This chapter is available at:
University of Chicago Press
https://academic.oup.com/chica...
