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Leeds A, Kakule D, Stalter L, Mbeke JK, Fawcett K. Group structure and individual relationships of sanctuary-living Grauer's gorillas (Gorilla beringei graueri). PLoS One 2024; 19:e0295561. [PMID: 38232054 DOI: 10.1371/journal.pone.0295561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 11/23/2023] [Indexed: 01/19/2024] Open
Abstract
The study of individual social relationships and group structure provides insights into a species' natural history and can inform management decisions for animals living in human care. The Gorilla Rehabilitation and Conservation Education (GRACE) center provides permanent sanctuary for a group of 14 Grauer's gorillas (Gorilla beringei graueri), a critically endangered and poorly studied subspecies of the genus gorilla, in the Democratic Republic of the Congo. We monitored the association patterns of the gorillas at GRACE over eight months and here describe their individual relationships and group structure via multiple social network statistics. The group was highly connected but associations between individuals were weak on average. Social network metrics describe that an adult female was the most gregarious and socially central individual within the group. In fact, adult females were the most gregarious and socially central on average. Group level association patterns were significantly correlated over the study period and across observation types, suggesting the group was socially stable during the eight month study period. The data collected in this study were done so by GRACE caregivers as part of their daily husbandry routine and provided important insights into this group's behavior, ultimately informing on their care, welfare and future release considerations. The methodological approaches implemented here are easily scalable to any primate sanctuary or care facility seeking to use data to inform husbandry and management procedures. Lastly, our study is the first social network analysis to be conducted on Grauer's gorillas and provides tentative insights into the behavior of this poorly studied subspecies. Though more research is needed to evaluate if the findings here are reflective of this subspecies' natural history or the idiosyncrasies of the group.
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Affiliation(s)
- Austin Leeds
- Animals, Science and Environment, Disney's Animal Kingdom®, Lake Buena Vista, Florida, United States of America
| | - Dalmas Kakule
- Gorilla Rehabilitation and Conservation Education Center, Kasugho, North Kivu, Democratic Republic of the Congo
| | - Laura Stalter
- Animals, Science and Environment, Disney's Animal Kingdom®, Lake Buena Vista, Florida, United States of America
| | - Jackson K Mbeke
- Gorilla Rehabilitation and Conservation Education Center, Kasugho, North Kivu, Democratic Republic of the Congo
| | - Katie Fawcett
- Gorilla Rehabilitation and Conservation Education Center, Kasugho, North Kivu, Democratic Republic of the Congo
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2
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Rosenbaum S, Kuzawa CW. The promise of great apes as model organisms for understanding the downstream consequences of early life experiences. Neurosci Biobehav Rev 2023; 152:105240. [PMID: 37211151 DOI: 10.1016/j.neubiorev.2023.105240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 05/23/2023]
Abstract
Early life experiences have a significant influence on adult health and aging processes in humans. Despite widespread interest in the evolutionary roots of this phenomenon, very little research on this topic has been conducted in humans' closest living relatives, the great apes. The longitudinal data sets that are now available on wild and captive great ape populations hold great promise to clarify the nature, evolutionary function, and mechanisms underlying these connections in species which share key human life history characteristics. Here, we explain features of great ape life history and socioecologies that make them of particular interest for this topic, as well as those that may limit their utility as comparative models; outline the ways in which available data are complementary to and extend the kinds of data that are available for humans; and review what is currently known about the connections among early life experiences, social behavior, and adult physiology and biological fitness in our closest living relatives. We conclude by highlighting key next steps for this emerging area of research.
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Affiliation(s)
| | - Christopher W Kuzawa
- Department of Anthropology, Northwestern University, USA; Institute for Policy Research, Northwestern University, USA
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3
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Kappeler PM, Benhaiem S, Fichtel C, Fromhage L, Höner OP, Jennions MD, Kaiser S, Krüger O, Schneider JM, Tuni C, van Schaik J, Goymann W. Sex roles and sex ratios in animals. Biol Rev Camb Philos Soc 2023; 98:462-480. [PMID: 36307924 DOI: 10.1111/brv.12915] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 10/12/2022] [Accepted: 10/14/2022] [Indexed: 11/29/2022]
Abstract
In species with separate sexes, females and males often differ in their morphology, physiology and behaviour. Such sex-specific traits are functionally linked to variation in reproductive competition, mate choice and parental care, which have all been linked to sex roles. At the 150th anniversary of Darwin's theory on sexual selection, the question of why patterns of sex roles vary within and across species remains a key topic in behavioural and evolutionary ecology. New theoretical, experimental and comparative evidence suggests that variation in the adult sex ratio (ASR) is a key driver of variation in sex roles. Here, we first define and discuss the historical emergence of the sex role concept, including recent criticisms and rebuttals. Second, we review the various sex ratios with a focus on ASR, and explore its theoretical links to sex roles. Third, we explore the causes, and especially the consequences, of biased ASRs, focusing on the results of correlational and experimental studies of the effect of ASR variation on mate choice, sexual conflict, parental care and mating systems, social behaviour, hormone physiology and fitness. We present evidence that animals in diverse societies are sensitive to variation in local ASR, even on short timescales, and propose explanations for conflicting results. We conclude with an overview of open questions in this field integrating demography, life history and behaviour.
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Affiliation(s)
- Peter M Kappeler
- Behavioral Ecology and Sociobiology Unit, German Primate Center - Leibniz Institute of Primatology, Kellnerweg 4, 37077, Göttingen, Germany
- Department of Sociobiology/Anthropology, University of Göttingen, Kellnerweg 6, 37077, Göttingen, Germany
| | - Sarah Benhaiem
- Department of Ecological Dynamics, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315, Berlin, Germany
| | - Claudia Fichtel
- Behavioral Ecology and Sociobiology Unit, German Primate Center - Leibniz Institute of Primatology, Kellnerweg 4, 37077, Göttingen, Germany
| | - Lutz Fromhage
- Department of Biological and Environmental Science, Ambiotica, University of Jyväskylä, PO Box 35, 40014, Jyväskylä, Finland
| | - Oliver P Höner
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Strasse 17, D-10315, Berlin, Germany
| | - Michael D Jennions
- Division of Ecology & Evolution, Research School of Biology, ANU College of Science, The Australian National University, RN Robertson Building, 46 Sullivans Creek Road, Canberra, ACT, 2600, Australia
| | - Sylvia Kaiser
- Department of Behavioural Biology, University of Münster, Badestr. 13, 48149, Münster, Germany
| | - Oliver Krüger
- Department of Animal Behavior, Bielefeld University, Morgenbreede 45, 33615, Bielefeld, Germany
| | - Jutta M Schneider
- Department of Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King Platz 3, 20146, Hamburg, Germany
| | - Cristina Tuni
- Department of Biology II, Ludwig Maximilians University of Munich, Großhaderner Str 2, 82152, Planegg-Martinsried, Germany
| | - Jaap van Schaik
- Applied Zoology and Nature Conservation, University of Greifswald, Loitzer Str. 26, 17489, Greifswald, Germany
| | - Wolfgang Goymann
- Department of Behavioural Neurobiology, Max Planck Institute for Ornithology, Eberhard-Gwinner-Str. 6a, D-82319, Seewiesen, Germany
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Dissecting the two mechanisms of scramble competition among the Virunga mountain gorillas. Behav Ecol Sociobiol 2021; 75:82. [PMID: 34776593 PMCID: PMC8550613 DOI: 10.1007/s00265-021-03016-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 03/24/2021] [Accepted: 03/30/2021] [Indexed: 11/30/2022]
Abstract
Abstract Two mechanisms have been proposed to explain why scramble competition can increase the travel requirements of individuals within larger groups. Firstly, individuals in larger groups may be more likely to encounter food sites where other group members have already eaten, leading to greater asynchronous “individual” travel to find fresh sites. Secondly, when food sites are aggregated into patches, larger groups may need to visit more patches to obtain the same amount of food per capita, leading to greater synchronous “group” travel between patches. If the first mechanism can be mitigated by increasing group spread, then we expect the second mechanism to be more sensitive to group size. Here, we examine the individual travel and group travel of the Virunga mountain gorillas, along with potential implications for the two mechanisms of scramble competition. Asynchronous individual travel accounted for 67% of the total travel time, and the remainder arose from group travel. Group spread increased significantly for larger groups, but not enough to prevent an increase in individual travel. Contrary to expectations, group travel decreased with size among most groups, and we found only limited evidence of patch depletion that would cause the second mechanism of scramble competition. Collectively, our results illustrate how the influence of group size can differ for individual travel versus group travel, just as it differs among species for overall travel. Studies that distinguish between the two mechanisms of scramble competition may enhance our understanding of ecological constraints upon group size, including potential differences between frugivores and folivores. Significance statement Feeding competition provides insight into how group size can influence the foraging patterns of social animals, but two key mechanisms are not typically compared. Firstly, larger groups may visit more patches to access the same amount of food per capita (group travel). Secondly, their individuals may also need to move past more spots where another member has already eaten (individual travel). Contrary to expectations, we found that group travel decreased with size for most groups of mountain gorillas, which may reflect extra travel by smaller groups to avoid larger groups. Individual travel increased with size in most groups, even though gorillas in larger groups compensated by spreading out over a broader area. The two mechanisms revealed patterns that were not apparent in our previous study of overall travel. Our approach may help to explain potential differences between folivores and frugivores.
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Fogel AS, McLean EM, Gordon JB, Archie EA, Tung J, Alberts SC. Genetic ancestry predicts male-female affiliation in a natural baboon hybrid zone. Anim Behav 2021; 180:249-268. [PMID: 34866638 PMCID: PMC8635413 DOI: 10.1016/j.anbehav.2021.07.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Opposite-sex social relationships are important predictors of fitness in many animals, including several group-living mammals. Consequently, understanding sources of variance in the tendency to form opposite-sex relationships is important for understanding social evolution. Genetic contributions are of particular interest due to their importance in long-term evolutionary change, but little is known about genetic effects on male-female relationships in social mammals, especially outside of the mating context. Here, we investigate the effects of genetic ancestry on male-female affiliative behaviour in a hybrid zone between the yellow baboon, Papio cynocephalus, and the anubis baboon, Papio anubis, in a population in which male-female social bonds are known predictors of life span. We place our analysis within the context of other social and demographic predictors of affiliative behaviour in baboons. Genetic ancestry was the most consistent predictor of opposite-sex affiliative behaviour we observed, with the exception of strong effects of dominance rank. Our results show that increased anubis genetic ancestry is associated with a subtle, but significantly higher, probability of opposite-sex affiliative behaviour, in both males and females. Additionally, pairs of anubis-like males and anubis-like females were the most likely to socially affiliate, resulting in moderate assortativity in grooming and proximity behaviour as a function of genetic ancestry. Our findings indicate that opposite-sex affiliative behaviour partially diverged during baboon evolution to differentiate yellow and anubis baboons, despite overall similarities in their social structures and mating systems. Furthermore, they suggest that affiliative behaviour may simultaneously promote and constrain baboon admixture, through additive and assortative effects of ancestry, respectively.
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Affiliation(s)
- Arielle S. Fogel
- University Program in Genetics and Genomics, Duke University, Durham, NC, U.S.A
- Department of Evolutionary Anthropology, Duke University, Durham, NC, U.S.A
| | - Emily M. McLean
- University Program in Genetics and Genomics, Duke University, Durham, NC, U.S.A
- Department of Biology, Duke University, Durham, NC, U.S.A
- Division of Natural Sciences and Mathematics, Oxford College of Emory University, Oxford, GA, U.S.A
| | | | - Elizabeth A. Archie
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, U.S.A
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
| | - Jenny Tung
- Department of Evolutionary Anthropology, Duke University, Durham, NC, U.S.A
- Department of Biology, Duke University, Durham, NC, U.S.A
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
- Duke Population Research Institute, Duke University, Durham, NC, U.S.A
| | - Susan C. Alberts
- Department of Evolutionary Anthropology, Duke University, Durham, NC, U.S.A
- Department of Biology, Duke University, Durham, NC, U.S.A
- Institute of Primate Research, National Museums of Kenya, Nairobi, Kenya
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Létang B, Mulot B, Alerte V, Bionda T, Britton L, ter Meulen T, Szánthó J, Guéry JP, Sueur C. Social proximities of developing gorilla males (Gorilla gorilla gorilla) in European zoos: The consequences of castration and social composition. Appl Anim Behav Sci 2021. [DOI: 10.1016/j.applanim.2020.105175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Mirville MO, Ridley AR, Samedi JPM, Vecellio V, Ndagijimana F, Stoinski TS, Grueter CC. Intragroup Behavioral Changes Following Intergroup Conflict in Mountain Gorillas (Gorilla beringei beringei). INT J PRIMATOL 2020. [DOI: 10.1007/s10764-020-00130-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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8
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Webber QM, Vander Wal E. Trends and perspectives on the use of animal social network analysis in behavioural ecology: a bibliometric approach. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.01.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Grueter CC, Hale J, Jin R, Judge D, Stoinski T. Infant handling by female mountain gorillas: Establishing its frequency, function, and (ir)relevance for life history evolution. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 168:744-749. [PMID: 30706446 DOI: 10.1002/ajpa.23791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 01/18/2019] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Infant handling describes cases in which youngsters are temporarily removed from the care of their mothers and "taken care of" (held, carried, etc.) by other conspecifics. Handlers may gain indirect fitness benefits from these actions and can practice mothering skills, thereby improving the odds of survival of their own infants. Great apes are notable for displaying little infant handling. Apart from anecdotal observations, no published data exist on infant handling in wild mountain gorillas. We tested two of the most pertinent explanations ("kin selection" and "learning to mother") in a wild population of mountain gorillas in Rwanda. We predicted that (a) nulliparous females would exhibit infant handling (i.e., carrying) more than parous females and (b) maternal kin would exhibit more infant handling than nonkin. METHODS We collated 8 years of data on infant carrying behavior collected in 13 groups monitored by the Dian Fossey Gorilla Fund's Karisoke Research Center. RESULTS Infant handling is an infrequent behavior (1,783 instances over 25,600 observation hours). A strong positive effect of relatedness and handler parity on the frequency of infant handling emerged. CONCLUSIONS While the nature of handler-infant interactions (affiliative, abusive, etc.) remains unstudied, they could constitute alloparental care and could therefore attenuate maternal energetic burden and ultimately allow increased birth rates. However, the rarity of this behavior makes it an unlikely contributor to mountain gorillas' relatively short interbirth intervals.
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Affiliation(s)
- Cyril C Grueter
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia.,Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Jennifer Hale
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Ruibing Jin
- Confucius Institute, The University of Western Australia, Claremont, Western Australia, Australia
| | - Debra Judge
- School of Human Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Tara Stoinski
- The Dian Fossey Gorilla Fund International, Atlanta, Georgia.,Zoo Atlanta, Atlanta, Georgia
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10
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Affiliation(s)
- Stephanie L Canington
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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12
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Kappeler PM. Sex roles and adult sex ratios: insights from mammalian biology and consequences for primate behaviour. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160321. [PMID: 28760762 PMCID: PMC5540861 DOI: 10.1098/rstb.2016.0321] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2017] [Indexed: 12/23/2022] Open
Abstract
Theoretical models and empirical studies in various taxa have identified important links between variation in sex roles and the number of adult males and females (adult sex ratio (ASR)) in a population. In this review, I examine these relationships in non-human primates. Because most existing theoretical models of the evolution of sex roles focus on the evolutionary origins of sex-biased behaviour, they offer only a general scaffold for predicting variation in sex roles among and within species. I argue that studies examining sex role variation at these more specific levels need to take social organization into account to identify meaningful levels for the measurement of ASR and to account for the fact that ASR and sex roles mutually influence each other. Moreover, taxon-specific life-history traits can constrain sex role flexibility and impact the operational sex ratio (OSR) by specifying the minimum length of female time outs from reproduction. Using examples from the primate literature, I highlight practical problems in estimating ASR and OSR. I then argue that interspecific variation in the occurrence of indirect forms of paternal care might indeed be linked to variation in ASR. Some studies also indicate that female aggression and bonding, as well as components of inter-sexual relationships, are sensitive to variation in ASR. Thus, links between primate sex roles and sex ratios merit further study, and such studies could prompt the development of more specific theoretical models that make realistic assumptions about taxon-specific life history and social organization.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'.
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Affiliation(s)
- Peter M Kappeler
- Wissenschaftskolleg zu Berlin, Wallotstrasse 19, 14193 Berlin, Germany
- Behavioral Ecology and Sociobiology Unit, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany
- Department of Sociobiology/Anthropology, University of Göttingen, Kellnerweg 6, 37077 Göttingen, Germany
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Rosenbaum S, Hirwa JP, Silk JB, Vigilant L, Stoinski TS. Infant Mortality Risk and Paternity Certainty Are Associated with Postnatal Maternal Behavior toward Adult Male Mountain Gorillas (Gorilla beringei beringei). PLoS One 2016; 11:e0147441. [PMID: 26863300 PMCID: PMC4749219 DOI: 10.1371/journal.pone.0147441] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 01/03/2016] [Indexed: 11/28/2022] Open
Abstract
Sexually selected infanticide is an important source of infant mortality in many mammalian species. In species with long-term male-female associations, females may benefit from male protection against infanticidal outsiders. We tested whether mountain gorilla (Gorilla beringei beringei) mothers in single and multi-male groups monitored by the Dian Fossey Gorilla Fund's Karisoke Research Center actively facilitated interactions between their infants and a potentially protective male. We also evaluated the criteria mothers in multi-male groups used to choose a preferred male social partner. In single male groups, where infanticide risk and paternity certainty are high, females with infants <1 year old spent more time near and affiliated more with males than females without young infants. In multi-male groups, where infanticide rates and paternity certainty are lower, mothers with new infants exhibited few behavioral changes toward males. The sole notable change was that females with young infants proportionally increased their time near males they previously spent little time near when compared to males they had previously preferred, perhaps to encourage paternity uncertainty and deter aggression. Rank was a much better predictor of females' social partner choice than paternity. Older infants (2-3 years) in multi-male groups mirrored their mothers' preferences for individual male social partners; 89% spent the most time in close proximity to the male their mother had spent the most time near when they were <1 year old. Observed discrepancies between female behavior in single and multi-male groups likely reflect different levels of postpartum intersexual conflict; in groups where paternity certainty and infanticide risk are both high, male-female interests align and females behave accordingly. This highlights the importance of considering individual and group-level variation when evaluating intersexual conflict across the reproductive cycle.
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Affiliation(s)
- Stacy Rosenbaum
- Department of Anthropology, University of California Los Angeles, Los Angeles, California, United States of America
| | | | - Joan B. Silk
- School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, United States of America
- Institute for Human Origins, Arizona State University, Tempe, Arizona, United States of America
| | - Linda Vigilant
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Tara S. Stoinski
- Dian Fossey Gorilla Fund International, Atlanta, Georgia, United States of America
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