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Harper CM, Patel BA. Trabecular bone variation in the gorilla calcaneus. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24939. [PMID: 38631677 DOI: 10.1002/ajpa.24939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 02/15/2024] [Accepted: 04/02/2024] [Indexed: 04/19/2024]
Abstract
OBJECTIVES Calcaneal external shape differs among nonhuman primates relative to locomotion. Such relationships between whole-bone calcaneal trabecular structure and locomotion, however, have yet to be studied. Here we analyze calcaneal trabecular architecture in Gorilla gorilla gorilla, Gorilla beringei beringei, and G. b. graueri to investigate general trends and fine-grained differences among gorilla taxa relative to locomotion. MATERIALS AND METHODS Calcanei were micro-CT scanned. A three-dimensional geometric morphometric sliding semilandmark analysis was carried out and the final landmark configurations used to position 156 volumes of interest. Trabecular thickness (Tb.Th), trabecular spacing (Tb.Sp), and bone volume fraction (BV/TV) were calculated using the BoneJ plugin for ImageJ and MATLAB. Non-parametric MANOVAs were run to test for significant differences among taxa in parameter raw values and z-scores. Parameter distributions were visualized using color maps and summarized using principal components analysis. RESULTS There are no significant differences in raw BV/TV or Tb.Th among gorillas, however G. b. beringei significantly differs in z-scores for both parameters (p = <0.0271). All three taxa exhibit relatively lower BV/TV and Tb.Th in the posterior half of the calcaneus. This gradation is exacerbated in G. b. beringei. G. b. graueri significantly differs from other taxa in Tb.Sp z-scores (p < 0.001) indicating a different spacing distribution. DISCUSSION Relatively higher Tb.Th and BV/TV in the anterior calcaneus among gorillas likely reflects higher forces associated with body mass (transmitted through the subtalar joint) relative to forces transferred through the posterior calcaneus. The different Tb.Sp pattern in G. b. graueri may reflect proposed differences in foot positioning during locomotion.
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Affiliation(s)
- Christine M Harper
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Biren A Patel
- Department of Integrative Anatomical Sciences, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
- Human and Evolutionary Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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2
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Grebe NM, Schmidt J, Eckardt W, Umuhoza R, Mayo D, Stoinski TS, Santymire RM, Rosenbaum S. Examining the dual hormone hypothesis in wild male mountain gorillas (Gorilla beringei beringei). Horm Behav 2024; 164:105588. [PMID: 38880022 DOI: 10.1016/j.yhbeh.2024.105588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 05/16/2024] [Accepted: 06/10/2024] [Indexed: 06/18/2024]
Abstract
The Challenge Hypothesis is an influential framework for understanding how androgens are involved in the promotion of competitive behavior during mating-related challenges and has been tested extensively in studies across scientific disciplines. Mixed support in psychological research led scholars to develop the Dual Hormone Hypothesis as a potential path forward, which argues that glucocorticoids moderate the relationship between androgens and status-striving. In the current study, we examine the Challenge Hypothesis and the Dual Hormone Hypothesis in wild male mountain gorillas, representing the first time the latter hypothesis has been tested in a non-human primate. In a sample of 30 adult males comprising over 600 days of observation, we find some limited support for the Challenge Hypothesis. Greater daily rates of targeted aggression toward other adult males corresponded to higher fecal androgen metabolites 1-2 days following observations, though this pattern did not fully generalize to dominance rank or other competitive behaviors examined. However, we find no support for the Dual Hormone Hypothesis: neither dominance rank nor any category of competitive behavior was predicted by the interaction between androgens and glucocorticoids. We close by discussing how this initial investigation might be leveraged toward the development of an expanded Dual Hormone Hypothesis that draws on the large evidence base in primate behavioral ecology.
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Affiliation(s)
- Nicholas M Grebe
- Department of Anthropology, University of Michigan, Ann Arbor, MI, United States of America.
| | - Josephine Schmidt
- Department of Anthropology, University of Michigan, Ann Arbor, MI, United States of America
| | | | | | - Dominic Mayo
- Department of Anthropology, University of Michigan, Ann Arbor, MI, United States of America
| | - Tara S Stoinski
- Dian Fossey Gorilla Fund, Atlanta, GA, United States of America
| | - Rachel M Santymire
- Department of Biology, Georgia State University, Atlanta, GA, United States of America
| | - Stacy Rosenbaum
- Department of Anthropology, University of Michigan, Ann Arbor, MI, United States of America
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Potel H, Niatou Singa FS, Cipolletta C, Neba Fuh T, Bardino G, Konyal E, Strampelli P, Henschel P, Masi S. Lethal combats in the forest among wild western gorillas. iScience 2024; 27:109437. [PMID: 38523787 PMCID: PMC10960106 DOI: 10.1016/j.isci.2024.109437] [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: 10/17/2023] [Revised: 01/13/2024] [Accepted: 03/04/2024] [Indexed: 03/26/2024] Open
Abstract
Lethal intergroup encounters occur in many species because of sexual selection. While documented in mountain gorillas, they are absent in western gorillas as, instead, it is predicted by their higher feeding (frugivory) and mate competition (single-vs. multi-male groups). We investigate whether the injuries on three dead silverbacks and one adult female from four groups of western gorillas in the Central African Republic, resulted from interactions with gorillas or leopards. We identified two distinct injury patterns caused by gorillas (isolated lacerations, round wounds) and leopards (punctures clustered on head/neck) by analyzing injuries caused by mountain gorillas and leopards to gorillas and non-gorilla species, respectively. The western gorilla injury pattern is similar to that of mountain gorillas suggesting that lethal encounters occur, albeit infrequently, as predicted by sexual selection in a one-male society. While sexual dimorphism and polygynous sociality favored the evolution of violent encounters, multiple males in groups may influence their frequency.
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Affiliation(s)
- Hugo Potel
- Ecoanthropologie, Centre National de la Recherche Scientifique/Muséum National d’Histoire Naturelle, University Paris Diderot, Sorbonne Paris Cité, Musée de l’Homme, Paris, France
| | | | - Chloé Cipolletta
- Dzanga-Sangha Protected Areas, World Wide Fund for Nature, Bangui, Central African Republic
| | - Terence Neba Fuh
- Dzanga-Sangha Protected Areas, World Wide Fund for Nature, Bangui, Central African Republic
| | - Giulia Bardino
- Ecoanthropologie, Centre National de la Recherche Scientifique/Muséum National d’Histoire Naturelle, University Paris Diderot, Sorbonne Paris Cité, Musée de l’Homme, Paris, France
- “La Sapienza” University, Department of Environmental and Evolutionary Biology, Rome, Italy
| | - Emmanuel Konyal
- Dzanga-Sangha Protected Areas, World Wide Fund for Nature, Bangui, Central African Republic
| | | | | | - Shelly Masi
- Ecoanthropologie, Centre National de la Recherche Scientifique/Muséum National d’Histoire Naturelle, University Paris Diderot, Sorbonne Paris Cité, Musée de l’Homme, Paris, France
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4
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Judson K, Sanz C, Ebombi TF, Massamba JM, Teberd P, Abea G, Mbebouti G, Matoumona JKB, Nkoussou EG, Zambarda A, Brogan S, Stephens C, Morgan D. Socioecological factors influencing intraspecific variation in ranging dynamics of western lowland gorillas (Gorilla gorilla gorilla) in Ndoki Forest. Am J Primatol 2024; 86:e23586. [PMID: 38151775 DOI: 10.1002/ajp.23586] [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: 02/17/2023] [Revised: 11/13/2023] [Accepted: 12/10/2023] [Indexed: 12/29/2023]
Abstract
Ranging dynamics are physical and behavioral representations of how different socioecological factors affect an organism's spatial decisions and space use strategies. Western lowland gorillas (Gorilla gorilla gorilla) are a model species to investigate the drivers of spatial dynamics based on both the natural variation in socioecological factors within the species and compared with their mountain gorilla counterparts. In this study, we evaluate the influences of resource seasonality and social dynamics on variation in home range size, utilization, and intergroup overlap among multiple gorilla groups over an 8-year study period in the northern Republic of Congo. This study shows that western lowland gorillas can have small home ranges comparable to mountain gorillas, rather than universally larger home ranges as previously supposed, and that home ranges are stable through time. The largest source of variation in space use was the degree of intergroup home range overlap. The study groups did not demonstrate intraspecific variation in range size nor changes in intergroup overlap with respect to seasonality of fruit resources, but all groups demonstrated expansion of monthly range and core area with group size, matching predictions of intragroup feeding competition. These findings highlight the potential impact of intergroup relationships on space use and prompt further research on the role of social dynamics in ranging strategies. In this study, we reveal a greater degree of variability and flexibility in gorilla ranging behavior than previously realized which is relevant to improving comparative studies and informing conservation strategies on behalf of these endangered primates.
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Affiliation(s)
- Kathryn Judson
- Department of Anthropology, Washington University in Saint Louis, Saint Louis, Missouri, USA
| | - Crickette Sanz
- Department of Anthropology, Washington University in Saint Louis, Saint Louis, Missouri, USA
- Wildlife Conservation Society, Congo Program, Brazzaville, Republic of Congo
| | | | - Jean Marie Massamba
- Wildlife Conservation Society, Congo Program, Brazzaville, Republic of Congo
| | - Prospère Teberd
- Wildlife Conservation Society, Congo Program, Brazzaville, Republic of Congo
| | - Gaston Abea
- Wildlife Conservation Society, Congo Program, Brazzaville, Republic of Congo
| | - Gaeton Mbebouti
- Wildlife Conservation Society, Congo Program, Brazzaville, Republic of Congo
| | | | | | - Alice Zambarda
- Wildlife Conservation Society, Congo Program, Brazzaville, Republic of Congo
| | - Sean Brogan
- Wildlife Conservation Society, Congo Program, Brazzaville, Republic of Congo
| | - Colleen Stephens
- Department of Anthropology, Washington University in Saint Louis, Saint Louis, Missouri, USA
| | - David Morgan
- Fisher Center for the Study and Conservation of Apes, Chicago, Illinois, USA
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Morrison RE, Ndayishimiye E, Stoinski TS, Eckardt W. Multiple mechanisms for inbreeding avoidance used simultaneously in a wild ape. Proc Biol Sci 2023; 290:20231808. [PMID: 37848059 PMCID: PMC10581766 DOI: 10.1098/rspb.2023.1808] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 09/21/2023] [Indexed: 10/19/2023] Open
Abstract
Mating with close kin can have considerable negative fitness consequences, which are expected to result in selective pressure for inbreeding avoidance mechanisms, such as dispersal, mate choice and post-copulatory biases. Captive studies have suggested that inbreeding avoidance through mate choice is far less widespread than expected and may be absent where other mechanisms already limit inbreeding. However, few studies have examined multiple mechanisms of inbreeding avoidance simultaneously, particularly in the wild. We use 13 years of detailed dispersal, copulation and paternity data from mountain gorillas to examine inbreeding avoidance. We find that partial dispersal of both sexes results in high kinship in multimale groups, but that copulations between close kin occur 40% less than expected. We find strong kin discrimination in mate choice, with significant avoidance of maternal kin but more limited avoidance of paternal kin. We find no evidence for post-copulatory inbreeding avoidance. Our analyses support familiarity-based mechanisms of kin identification and age-based avoidance that limits mating between fathers and daughters in their natal group. Our findings demonstrate that multiple complementary mechanisms for inbreeding avoidance can evolve in a single species and suggest that inbreeding avoidance through mate choice may enable more flexible dispersal systems to evolve.
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Affiliation(s)
- Robin E. Morrison
- Dian Fossey Gorilla Fund, Musanze, Rwanda
- Human Evolutionary Ecology Group, Department of Evolutionary Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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Teberd P, Sanz C, Zambarda A, Kienast I, Ebombi TF, Abea G, Mengoga D, Makisso JN, Kunz J, Judson K, Stephens C, Morgan D. Path To Acceptance and Refined Practices for Habituating Western Lowland Gorillas. Primates 2023:10.1007/s10329-023-01086-5. [PMID: 37656335 DOI: 10.1007/s10329-023-01086-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 08/03/2023] [Indexed: 09/02/2023]
Abstract
Although western lowland gorillas (Gorilla gorilla gorilla) are the most numerous and widespread gorilla subspecies, they have remained relatively unstudied. International tourism has been initiated at several sites in the Congo Basin, which necessitates habituation of gorillas to human presence. However, habituation has proven difficult due to several obstacles, including relatively low population densities, small group sizes, and thick understory vegetation. In this article, we propose refinements to current approaches to habituating western lowland gorillas that maximize safety and emphasize adaptive responses based on empirical evidence. In addition to reviewing published reports, our approach is informed by the recent habituation of the Mététélé group in the Djéké Triangle, an area that was recently included in the Nouabalé-Ndoki National Park in Republic of Congo. We evaluate progress in habituation according to time spent in the presence of the gorillas and their reactions to humans. The Mététélé group is composed of 14 individuals and has a home range that overlaps with two habituated gorilla groups. Early in the habituation process, we discovered that three of Mététélé's group members were individuals who had previously been habituated as members of other groups. The presence of these individuals expedited the habituation process. Familiarity with humans may have also reduced aggressive responses during the habituation process. The overall result is a refined step-by-step approach to the habituation of western lowland gorillas that includes procedures and assessments to meet best-practice guidelines and ensure the wellbeing of both gorillas and humans.
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Affiliation(s)
- Prospère Teberd
- Wildlife Conservation Society, Congo Program, BP, 14537, Brazzaville, Republic of Congo.
| | - Crickette Sanz
- Wildlife Conservation Society, Congo Program, BP, 14537, Brazzaville, Republic of Congo
- Department of Anthropology, Washington University in Saint Louis, 1 Brookings Drive, Saint Louis, Missouri, 63130, USA
| | - Alice Zambarda
- Wildlife Conservation Society, Congo Program, BP, 14537, Brazzaville, Republic of Congo
| | - Ivonne Kienast
- Department of Natural Resources and the Environment, Cornell University, Ithaca, NY, 14850, USA
- K. Lisa Yang Center for Conservation Bioacoustics, Cornell Lab of Ornithology, Cornell University, Ithaca, NY, 14850, USA
| | | | - Gaston Abea
- Wildlife Conservation Society, Congo Program, BP, 14537, Brazzaville, Republic of Congo
| | - Donatien Mengoga
- Wildlife Conservation Society, Congo Program, BP, 14537, Brazzaville, Republic of Congo
| | - Jean Noel Makisso
- Wildlife Conservation Society, Congo Program, BP, 14537, Brazzaville, Republic of Congo
| | - Julia Kunz
- Wildlife Conservation Society, Congo Program, BP, 14537, Brazzaville, Republic of Congo
| | - Kathryn Judson
- Department of Anthropology, Washington University in Saint Louis, 1 Brookings Drive, Saint Louis, Missouri, 63130, USA
| | - Colleen Stephens
- Department of Anthropology, Washington University in Saint Louis, 1 Brookings Drive, Saint Louis, Missouri, 63130, USA
| | - David Morgan
- Fisher Center for the Study and Conservation of Apes, Lincoln Park Zoo, 2001 N. Clark Street, Chicago, IL, 60614, USA
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Harper CM, Roach CS, Goldstein DM, Sylvester AD. Morphological variation of the Pan talus relative to that of Gorilla. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023. [PMID: 37300336 DOI: 10.1002/ajpa.24796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 03/27/2023] [Accepted: 05/27/2023] [Indexed: 06/12/2023]
Abstract
OBJECTIVES Differences in talar articular morphology relative to locomotion have recently been found within Pan and Gorilla. Whole-bone talar morphology within, and shared variation among, Pan and Gorilla (sub)species, however, has yet to be investigated. Here we separately analyze talar external shape within Pan (P. t. troglodytes, P. t. schweinfurthii, P. t. verus, P. paniscus) and Gorilla (G. g. gorilla, G. b. beringei, G. b. graueri) relative to degree of arboreality and body size. Pan and Gorilla are additionally analyzed together to determine if consistent shape differences exist within the genera. MATERIALS AND METHODS Talar external shape was quantified using a weighted spherical harmonic analysis. Shape variation both within and among Pan and Gorilla was described using principal component analyses. Root mean square distances were calculated between taxon averages, and resampling statistics conducted to test for pairwise differences. RESULTS P. t. verus (most arboreal Pan) talar shape significantly differs from other Pan taxa (p < 0.05 for pairwise comparisons) driven by more asymmetrical trochlear rims and a medially-set talar head. P. t. troglodytes, P. t. schweinfurthii, and P. paniscus do not significantly differ (p > 0.05 for pairwise comparisons). All gorilla taxa exhibit significantly different talar morphologies (p < 0.007 for pairwise comparisons). The more terrestrial subspecies of G. beringei and P. troglodytes exhibit a superoinferiorly taller talar head/neck complex. DISCUSSION P. t. verus exhibits talar morphologies that have been previously related to more frequent arboreality. The adaptations in the more terrestrial G. beringei and P. troglodytes subspecies may serve to facilitate load transmission.
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Affiliation(s)
- Christine M Harper
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Caleigh S Roach
- Krieger School of Arts and Sciences, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Deanna M Goldstein
- Department of Anatomical Sciences, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York, USA
| | - Adam D Sylvester
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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8
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Morrison RE, Eckardt W, Stoinski TS, Rosenbaum S. Cumulative early-life adversity does not predict reduced adult longevity in wild gorillas. Curr Biol 2023; 33:2307-2314.e4. [PMID: 37192615 PMCID: PMC10264970 DOI: 10.1016/j.cub.2023.04.051] [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: 12/20/2022] [Revised: 02/24/2023] [Accepted: 04/21/2023] [Indexed: 05/18/2023]
Abstract
Extensive research across fields has repeatedly confirmed that early-life adversity (ELA) is a major selective force for many taxa, in part via its ties to adult health and longevity.1,2,3 Negative effects of ELA on adult outcomes have been documented in a wide range of species, from fish to birds to humans.4 We used 55 years of long-term data collected on 253 wild mountain gorillas to examine the effects of six putative sources of ELA on survival, both individually and cumulatively. Although cumulative ELA was associated with high mortality in early life, we found no evidence that it had detrimental consequences for survival later in life. Experiencing three or more forms of ELA was associated with greater longevity, with a 70% reduction in the risk of death across adulthood, driven specifically by greater longevity in males. Although this higher survival in later life is likely a consequence of sex-specific viability selection5 during early life due to the immediate mortality consequences of adverse experiences, patterns in our data also suggest that gorillas have significant resilience to ELA. Our findings demonstrate that the detrimental consequences of ELA on later life survival are not universal, and indeed largely absent in one of humans' closest living relatives. This raises important questions about the biological roots of sensitivity to early experiences and the protective mechanisms that contribute to resiliency in gorillas, which could be critical for understanding how best to encourage similar resiliency to early-life shocks in humans.
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Affiliation(s)
- Robin E Morrison
- Dian Fossey Gorilla Fund, PO Box 105, Musanze, Rwanda; Centre for Research in Animal Behaviour, Department of Psychology, University of Exeter, Exeter EX4 4QG, UK.
| | | | | | - Stacy Rosenbaum
- Department of Anthropology, University of Michigan-Ann Arbor, Ann Arbor, MI 48109, USA.
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Morrison RE, Hirwa JP, Ndagijimana F, Vecellio V, Eckardt W, Stoinski TS. Cascading effects of social dynamics on the reproduction, survival, and population growth of mountain gorillas. Anim Conserv 2022. [DOI: 10.1111/acv.12830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- R. E. Morrison
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
- Centre for Research in Animal Behaviour, Department of Psychology University of Exeter Exeter UK
| | - J. P. Hirwa
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
| | - F. Ndagijimana
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
| | - V. Vecellio
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
| | - W. Eckardt
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
| | - T. S. Stoinski
- Dian Fossey Gorilla Fund, Ellen DeGeneres Campus of the Dian Fossey Gorilla Fund Kinigi Rwanda
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Robbins AM, Manguette ML, Breuer T, Groenenberg M, Parnell RJ, Stephan C, Stokes EJ, Robbins MM. Population dynamics of western gorillas at Mbeli Bai. PLoS One 2022; 17:e0275635. [PMID: 36260834 PMCID: PMC9581538 DOI: 10.1371/journal.pone.0275635] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/20/2022] [Indexed: 11/19/2022] Open
Abstract
Long-term studies of population dynamics can provide insights into life history theory, population ecology, socioecology, conservation biology and wildlife management. Here we examine 25 years of population dynamics of western gorillas at Mbeli Bai, a swampy forest clearing in Nouabalé-Ndoki National Park, the Republic of Congo. The Mbeli population more than doubled from 101 to 226 gorillas during the study. After adjusting for a net influx of gorillas into the study population, the increase represents an inherent growth rate of 0.7% per year, with 95% confidence limits between -0.7% and 2.6%. The influx of gorillas mainly involved immigration of individuals into existing study groups (social dispersal), but it also included the appearance of a few previously unknown groups (locational dispersal). The average group size did not change significantly during the study, which is consistent with the possibility that western gorillas face socioecological constraints on group size, even when the population is increasing. We found no significant evidence of density dependence on female reproductive success or male mating competition. The distribution of gorillas among age/sex categories also did not change significantly, which suggests that the population had a stable age structure. Our results provide evidence of population stability or growth for some western gorillas (albeit within a small area). The results highlight the value of law enforcement, long-term monitoring, and protected areas; but they do not diminish the importance of improving conservation for this critically endangered species.
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Affiliation(s)
- Andrew M. Robbins
- Wildlife Conservation Society–Congo Program, Brazzaville, Republic of Congo
- * E-mail:
| | - Marie L. Manguette
- Wildlife Conservation Society–Congo Program, Brazzaville, Republic of Congo
- Nouabalé-Ndoki Foundation, Brazzaville, Republic of Congo
| | - Thomas Breuer
- Nouabalé-Ndoki Foundation, Brazzaville, Republic of Congo
- Division of Developmental Biology, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | | | - Richard J. Parnell
- Wildlife Conservation Society, Global Conservation Program, Bronx, NY, United States of America
| | - Claudia Stephan
- Wildlife Conservation Society–Congo Program, Brazzaville, Republic of Congo
- Nouabalé-Ndoki Foundation, Brazzaville, Republic of Congo
- Division of Developmental Biology, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Emma J. Stokes
- Wildlife Conservation Society, Global Conservation Program, Bronx, NY, United States of America
| | - Martha M. Robbins
- Wildlife Conservation Society–Congo Program, Brazzaville, Republic of Congo
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Teichroeb JA, Adams FV, Khwaja A, Stapelfeldt K, Stead SM. Tight quarters: ranging and feeding competition in a Colobus angolensis ruwenzorii multilevel society occupying a fragmented habitat. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03166-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Petrželková K, Samaš P, Romportl D, Uwamahoro C, Červená B, Pafčo B, Prokopová T, Cameira R, Granjon A, Shapiro A, Bahizi M, Nziza J, Noheri J, Syaluha E, Eckardt W, Ndagijimana F, Šlapeta J, Modrý D, Gilardi K, Muvunyi R, Uwingeli P, Mudakikwa A, Mapilanga J, Kalonji A, Hickey J, Cranfield M. Ecological drivers of helminth infection patterns in the Virunga Massif mountain gorilla population. Int J Parasitol Parasites Wildl 2022; 17:174-184. [PMID: 35145846 PMCID: PMC8802862 DOI: 10.1016/j.ijppaw.2022.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/07/2022] [Accepted: 01/17/2022] [Indexed: 01/16/2023]
Abstract
The Virunga Massif mountain gorilla population has been periodically monitored since the early 1970s, with gradually increasing effort. The population declined drastically in the 1970s, but the numbers stabilized in the 1980s. Since then, the population has been steadily increasing within their limited habitat fragment that is surrounded by a dense human population. We examined fecal samples collected during the Virunga 2015-2016 surveys in monitored and unmonitored gorilla groups and quantified strongylid and tapeworm infections using egg counts per gram to determine environmental and host factors that shape these helminth infections. We showed that higher strongylid infections were present in gorilla groups with smaller size of the 500-m buffered minimum-convex polygon (MCP) of detected nest sites per gorilla group, but in higher gorilla densities and inhabiting vegetation types occurring at higher elevations with higher precipitation and lower temperatures. On the contrary, the impact of monitoring (habituation) was minor, detected in tapeworms and only when in the interaction with environmental variables and MCP area. Our results suggest that the Virunga mountain gorilla population may be partially regulated by strongylid nematodes at higher gorilla densities. New health challenges are probably emerging among mountain gorillas because of the success of conservation efforts, as manifested by significant increases in gorilla numbers in recent decades, but few possibilities for the population expansion due to limited amounts of habitat.
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Affiliation(s)
- K.J. Petrželková
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic
- Liberec Zoo, Liberec, Czech Republic
| | - P. Samaš
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - D. Romportl
- Department of Physical Geography and Geoecology, Faculty of Science, Charles University, Prague, Czech Republic
| | | | - B. Červená
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic
| | - B. Pafčo
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - T. Prokopová
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic
| | - R. Cameira
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic
| | - A.C. Granjon
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - A. Shapiro
- Here + There Mapping Solutions, Berlin, Germany
| | - M. Bahizi
- Gorilla Doctors (MGVP, Inc.), Davis, CA, USA
| | - J. Nziza
- Gorilla Doctors (MGVP, Inc.), Davis, CA, USA
| | - J.B. Noheri
- Gorilla Doctors (MGVP, Inc.), Davis, CA, USA
| | | | - W. Eckardt
- Dian Fossey Gorilla Fund, Musanze, Rwanda
| | | | - J. Šlapeta
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, New South Wales 2006, Australia
| | - D. Modrý
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Czech Republic
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences, Brno, Czech Republic
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
- Department of Veterinary Sciences/CINeZ, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Prague, Czech Republic
| | - K. Gilardi
- Gorilla Doctors (MGVP, Inc.), Davis, CA, USA
- School of Veterinary Medicine, University of California, Davis, CA, USA
| | - R. Muvunyi
- Rwanda Development Board, Kigali, Rwanda
| | | | | | - J. Mapilanga
- Institut Congolais pour la Conservation de la Nature, Kinshasa, Congo
| | - A. Kalonji
- Institut Congolais pour la Conservation de la Nature, Parc National de Kahuzi Biega, Bukavu, Congo
| | - J.R. Hickey
- International Gorilla Conservation Programme, Kigali, Rwanda
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13
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Rosenbaum S, Silk JB. Pathways to paternal care in primates. Evol Anthropol 2022; 31:245-262. [PMID: 35289027 DOI: 10.1002/evan.21942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 10/01/2021] [Accepted: 01/21/2022] [Indexed: 11/06/2022]
Abstract
Natural selection will favor male care when males have limited alternative mating opportunities, can invest in their own offspring, and when care enhances males' fitness. These conditions are easiest to fulfill in pair-bonded species, but neither male care nor stable "breeding bonds" that facilitate it are limited to pair-bonded species. We review evidence of paternal care and extended breeding bonds in owl monkeys, baboons, Assamese macaques, mountain gorillas, and chimpanzees. The data, which span social/mating systems and ecologies, suggest that there are multiple pathways by which conditions conducive to male care can arise. This diversity highlights the difficulty of making inferences about the emergence of male care in early hominins based on single traits visible in the fossil record. We discuss what types of data are most needed and the questions yet to be answered about the evolution of male care and extended breeding bonds in the primate order.
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Affiliation(s)
- Stacy Rosenbaum
- Department of Anthropology, University of Michigan, Ann Arbor, Michigan, USA
| | - Joan B Silk
- School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, USA.,Institute of Human Origins, Arizona State University, Tempe, Arizona, USA
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14
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Ruff CB, Junno JA, Burgess ML, Canington SL, Harper C, Mudakikwa A, McFarlin SC. Body proportions and environmental adaptation in gorillas. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 177:501-529. [PMID: 36787793 DOI: 10.1002/ajpa.24443] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 07/22/2021] [Accepted: 10/19/2021] [Indexed: 11/07/2022]
Abstract
OBJECTIVES Limb length and trunk proportions are determined in a large, taxonomically and environmentally diverse sample of gorillas and related to variation in locomotion, climate, altitude, and diet. MATERIALS AND METHODS The sample includes 299 gorilla skeletons, 115 of which are infants and juveniles, distributed between western lowland (G. gorilla gorilla), low and high elevation grauer (G. beringei graueri), and Virunga mountain gorillas (G. b. beringei). Limb bone and vertebral column lengths scaled to body mass are compared between subgroups by age group. RESULTS All G. beringei have relatively short 3rd metapodials and manual proximal phalanges compared to G. gorilla, and this difference is apparent in infancy. All G. beringei also have shortened total limb lengths relative to either body mass or vertebral column length, although patterns of variation in individual skeletal elements are more complex, and infants do not display the same patterns as adults. Mountain gorillas have relatively long clavicles, present in infancy, and a relatively long thoracic (but not lumbosacral) vertebral column. DISCUSSION A variety of environmental factors likely contributed to observed patterns of morphological variation among extant gorillas. We interpret the short hand and foot bones of all G. beringei as genetic adaptations to greater terrestriality in the last common ancestor of G. beringei; variation in other limb lengths to climatic adaptation, both genetic and developmental; and the larger thorax of G. b. beringei to adaptation to reduced oxygen pressure at high altitudes, again as a product of both genetic differences and environmental influences during development.
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Affiliation(s)
- Christopher B Ruff
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - M Loring Burgess
- Peabody Museum of Archaeology and Ethnology, Harvard University, Cambridge, Massachusetts, USA
| | - Stephanie L Canington
- Center for Functional Anatomy and Evolution, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christine Harper
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, New Jersey, USA
| | - Antoine Mudakikwa
- Rwanda Development Board, Department of Tourism and Conservation, Kigali, Rwanda
| | - Shannon C McFarlin
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, District of Columbia, USA.,Human Origins Program, Smithsonian's National Museum of Natural History, Washington, District of Columbia, USA
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15
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Whittier CA, Nutter FB, Johnson PLF, Cross P, Lloyd-Smith JO, Slenning BD, Stoskopf MK. Population structure, intergroup interaction, and human contact govern infectious disease impacts in mountain gorilla populations. Am J Primatol 2021; 84:e23350. [PMID: 34878678 DOI: 10.1002/ajp.23350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 10/13/2021] [Accepted: 11/01/2021] [Indexed: 01/16/2023]
Abstract
Infectious zoonotic diseases are a threat to wildlife conservation and global health. They are especially a concern for wild apes, which are vulnerable to many human infectious diseases. As ecotourism, deforestation, and great ape field research increase, the threat of human-sourced infections to wild populations becomes more substantial and could result in devastating population declines. The endangered mountain gorillas (Gorilla beringei beringei) of the Virunga Massif in east-central Africa suffer periodic disease outbreaks and are exposed to infections from human-sourced pathogens. It is important to understand the possible risks of disease introduction and spread in this population and how human contact may facilitate disease transmission. Here we present and evaluate an individual-based, stochastic, discrete-time disease transmission model to predict epidemic outcomes and better understand health risks to the Virunga mountain gorilla population. To model disease transmission we have derived estimates for gorilla contact, interaction, and migration rates. The model shows that the social structure of gorilla populations plays a profound role in governing disease impacts with subdivided populations experiencing less than 25% of the outbreak levels of a single homogeneous population. It predicts that gorilla group dispersal and limited group interactions are strong factors in preventing widespread population-level outbreaks of infectious disease after such diseases have been introduced into the population. However, even a moderate amount of human contact increases disease spread and can lead to population-level outbreaks.
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Affiliation(s)
- Christopher A Whittier
- Department of Infectious Disease and Global Health & Tufts Center for Conservation Medicine, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
| | - Felicia B Nutter
- Department of Infectious Disease and Global Health & Tufts Center for Conservation Medicine, Cummings School of Veterinary Medicine at Tufts University, North Grafton, Massachusetts, USA
| | - Philip L F Johnson
- Department of Biology, University of Maryland, College Park, Maryland, USA
| | - Paul Cross
- Department of Interior, US Geological Survey, Northern Rocky Mountain Science Center, Bozeman, Montana, USA
| | - James O Lloyd-Smith
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, California, USA
| | - Barrett D Slenning
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - Michael K Stoskopf
- Environmental Medicine Consortium, North Carolina State University College of Veterinary Medicine, Raleigh, North Carolina, USA.,Department of Clinical Sciences, North Carolina State University College of Veterinary Medicine, Raleigh, North Carolina, USA
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16
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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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17
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Colchero F, Eckardt W, Stoinski T. Exploring the potential effect of COVID-19 on an endangered great ape. Sci Rep 2021; 11:20715. [PMID: 34675230 PMCID: PMC8531408 DOI: 10.1038/s41598-021-00061-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 10/05/2021] [Indexed: 11/09/2022] Open
Abstract
The current COVID-19 pandemic has created unmeasurable damages to society at a global level, from the irreplaceable loss of life, to the massive economic losses. In addition, the disease threatens further biodiversity loss. Due to their shared physiology with humans, primates, and particularly great apes, are susceptible to the disease. However, it is still uncertain how their populations would respond in case of infection. Here, we combine stochastic population and epidemiological models to simulate the range of potential effects of COVID-19 on the probability of extinction of mountain gorillas. We find that extinction is sharply driven by increases in the basic reproductive number and that the probability of extinction is greatly exacerbated if the immunity lasts less than 6 months. These results stress the need to limit exposure of the mountain gorilla population, the park personnel and visitors, as well as the potential of vaccination campaigns to extend the immunity duration.
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Affiliation(s)
- Fernando Colchero
- Department of Mathematics and Computer Science, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.
- Interdisciplinary Center on Population Dynamics, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.
| | - Winnie Eckardt
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave SE, Atlanta, GA, 30315, USA
| | - Tara Stoinski
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave SE, Atlanta, GA, 30315, USA
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18
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Shakeri YN, White KS, Waite JN. Staying close to home: Ecological constraints on space use and range fidelity in a mountain ungulate. Ecol Evol 2021; 11:11051-11064. [PMID: 34429902 PMCID: PMC8366887 DOI: 10.1002/ece3.7893] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 05/22/2021] [Accepted: 06/22/2021] [Indexed: 11/15/2022] Open
Abstract
Understanding patterns of animal space use and range fidelity has important implications for species and habitat conservation. For species that live in highly seasonal environments, such as mountain goats (Oreamnos americanus), spatial use patterns are expected to vary in relation to seasonal changes in environmental conditions and sex- or age-specific selection pressures. To address hypotheses about sex, age, and seasonality influence on space-use ecology, we collected GPS location data from 263 radio-collared mountain goats (males, n = 140; females, n = 123) in coastal Alaska during 2005-2016. Location data were analyzed to derive seasonal and sex-specific fixed-kernel home range estimates and to quantify the degree of seasonal range and utilization distribution overlap. Overall, we determined that home range size was smallest during winter, expanded coincident with the onset of green-up and parturition, and was largest during summer. Home range size of males and females did not differ significantly during winter, but females had larger home ranges than males during summer, a relationship that was switched during the mating season. Pairwise comparisons involving individual females across subsequent years indicated home ranges were significantly smaller during years when they gave birth to offspring. Mountain goats exhibited a strong degree of range fidelity, and 99% (n = 138) of individual animals returned to their previous year's seasonal range with an average annual Bhattacharyya's affinity utilization distribution overlap index of 68%. Similarity of seasonal home range utilization distributions varied in relation to sex and season in some respects. Home range overlap was highest during the summer vegetation growing season, particularly among females. These findings advance our understanding about how environmental variation and sex- and age-related reproductive constraints influence space use and range fidelity among alpine ungulates. Documentation of the high degree of range fidelity among mountain goats has important conservation implications in landscapes increasingly altered by anthropogenic activities.
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Affiliation(s)
- Yasaman N. Shakeri
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaskaUSA
- Wyoming Cooperative Fish and Wildlife Research UnitDepartment of Zoology and PhysiologyUniversity of WyomingLaramieWyomingUSA
| | - Kevin S. White
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaskaUSA
| | - Jason N. Waite
- Division of Wildlife ConservationAlaska Department of Fish and GameJuneauAlaskaUSA
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19
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Rosenbaum S, Eckardt W, Stoinski TS, Umuhoza R, Kuzawa CW, Santymire RM. Group structure, but not dominance rank, predicts fecal androgen metabolite concentrations of wild male mountain gorillas (Gorilla beringei beringei). Am J Primatol 2021; 83:e23295. [PMID: 34223661 DOI: 10.1002/ajp.23295] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/24/2021] [Accepted: 06/06/2021] [Indexed: 11/11/2022]
Abstract
Androgens are important mediators of male-male competition in many primate species. Male gorillas' morphology is consistent with a reproductive strategy that relies heavily on androgen-dependent traits (e.g., extreme size and muscle mass). Despite possessing characteristics typical of species with an exclusively single-male group structure, multimale groups with strong dominance hierarchies are common in mountain gorillas. Theory predicts that androgens should mediate their dominance hierarchies, and potentially vary with the type of group males live in. We validated the use of a testosterone enzyme immunoassay (T-EIA R156/7, CJ Munro, UC-Davis) for use with mountain gorilla fecal material by (1) examining individual-level androgen responses to competitive events, and (2) isolating assay-specific hormone metabolites via high-performance liquid chromatography. Males had large (2.6- and 6.5-fold), temporary increases in fecal androgen metabolite (FAM) after competitive events, and most captured metabolites were testosterone or 5α-dihydrotestosterone-like androgens. We then examined the relationship between males' dominance ranks, group type, and FAM concentrations. Males in single-male groups had higher FAM concentrations than males in multimale groups, and a small pool of samples from solitary males suggested they may have lower FAM than group-living peers. However, data from two different time periods (n = 1610 samples) indicated there was no clear relationship between rank and FAM concentrations, confirming results from the larger of two prior studies that measured urinary androgens. These findings highlight the need for additional research to clarify the surprising lack of a dominance hierarchy/androgen relationship in mountain gorillas.
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Affiliation(s)
- Stacy Rosenbaum
- Department of Anthropology, University of Michigan, Ann Arbor, Michigan, USA.,Davee Center for Epidemiology and Endocrinology, Lincoln Park Zoo, Chicago, Illinois, USA
| | - Winnie Eckardt
- Karisoke Research Center, Musanze, Rwanda.,The Dian Fossey Gorilla Fund, Atlanta, Georgia, USA
| | | | | | - Christopher W Kuzawa
- Department of Anthropology, Northwestern University, Evanston, Illinois, USA.,Institute for Policy Research, Northwestern University, Evanston, Illinois, USA
| | - Rachel M Santymire
- Davee Center for Epidemiology and Endocrinology, Lincoln Park Zoo, Chicago, Illinois, USA
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20
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Petrželková KJ, Uwamahoro C, Pafčo B, Červená B, Samaš P, Mudakikwa A, Muvunyi R, Uwingeli P, Gilardi K, Nziza J, Noheri JB, Eckardt W, Ndagijimana F, Ssebide B, Okwirokello R, Nizeyimana F, Syaluha EK, Nzayisenga G, Flores Girón L, Bahizi M, Ntwari AE, Lukusa JP, Tumushime JC, Mangura D, Mapilanga J, Kalonji A, Aruho R, Stryková A, Tehlarová Z, Cameira R, Lowenstine L, Šlapeta J, Romportl D, Ferrari N, Cranfield M, Modrý D. Heterogeneity in patterns of helminth infections across populations of mountain gorillas (Gorilla beringei beringei). Sci Rep 2021; 11:10869. [PMID: 34035316 PMCID: PMC8149636 DOI: 10.1038/s41598-021-89283-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 04/20/2021] [Indexed: 02/04/2023] Open
Abstract
Conservation efforts have led to the recovery of the endangered mountain gorilla populations. Due to their limited potential for spatial expansion, population densities increased, which may alter the epidemiology of infectious diseases. Recently, clinical gastrointestinal illnesses linked to helminth infections have been recorded in both gorilla populations. To understand drivers and patterns of helminth infections we quantified strongylid and tapeworm infections across both Virunga Massif and Bwindi populations using fecal egg counts. We assessed the impact of age, sex, group size, season and spatial differences used as a proxy, which reflects observed variation in the occurrence of gastrointestinal problems, vegetation types, gorilla subpopulation growth and associated social structure on helminth infections. We revealed striking geographic differences in strongylid infections with higher egg counts mostly in areas with high occurrences of gastrointestinal disease. Increased helminth egg counts were also associated with decreasing group size in some areas. Observed spatial differences may reflect mutual effects of variations in subpopulation growth rates, gorilla social structure, and vegetation associated with altitude across mountain gorilla habitat. Helminth infection intensities in Virunga gorillas were lowest in the youngest and the oldest animals. Elucidating parasite infection patterns of endangered species with low genetic diversity is crucial for their conservation management.
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Affiliation(s)
- Klara J. Petrželková
- grid.418095.10000 0001 1015 3316Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic ,grid.418338.50000 0001 2255 8513Institute of Parasitology, Biology Centre, The Czech Academy of Sciences, Ceske Budejovice, Czech Republic ,Liberec Zoo, Liberec, Czech Republic
| | | | - Barbora Pafčo
- grid.418095.10000 0001 1015 3316Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic
| | - Barbora Červená
- grid.418095.10000 0001 1015 3316Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic ,Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic
| | - Peter Samaš
- grid.418095.10000 0001 1015 3316Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic
| | - Antoine Mudakikwa
- grid.508147.f0000 0000 9490 3868Rwanda Development Board, Kigali, Rwanda
| | - Richard Muvunyi
- grid.508147.f0000 0000 9490 3868Rwanda Development Board, Kigali, Rwanda
| | - Prosper Uwingeli
- grid.508147.f0000 0000 9490 3868Rwanda Development Board, Kigali, Rwanda
| | | | - Julius Nziza
- grid.508041.8Gorilla Doctors (MGVP, Inc.), Davis, CA USA
| | | | | | | | - Benard Ssebide
- grid.508041.8Gorilla Doctors (MGVP, Inc.), Davis, CA USA
| | | | | | | | | | - Luis Flores Girón
- Centre de Recherche en Sciences Naturelles de Lwiro, Lwiro, Democratic Republic of Congo ,Lwiro Primate Rehabilitation Center, Democratic Republic of Congo and Ivan Carter Wildlife Conservation Alliance, Orlando, FL USA
| | - Méthode Bahizi
- grid.508041.8Gorilla Doctors (MGVP, Inc.), Davis, CA USA
| | | | | | | | - Damien Mangura
- grid.508041.8Gorilla Doctors (MGVP, Inc.), Davis, CA USA
| | - Jeff Mapilanga
- Institut Congolais pour la Conservation de la Nature, Kinshasa, Democratic Republic of Congo
| | - Arthur Kalonji
- Institut Congolais pour la Conservation de la Nature, Parc National de Kahuzi Biega, Bukavu, Democratic Republic of Congo
| | - Robert Aruho
- grid.463699.7Uganda Wildlife Authority, Kampala, Uganda
| | - Anna Stryková
- Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic
| | - Zuzana Tehlarová
- grid.418095.10000 0001 1015 3316Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic
| | - Rita Cameira
- grid.418095.10000 0001 1015 3316Institute of Vertebrate Biology, The Czech Academy of Sciences, Brno, Czech Republic ,Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic
| | - Linda Lowenstine
- grid.27860.3b0000 0004 1936 9684School of Veterinary Medicine, University of California Davis, Davis, CA USA
| | - Jan Šlapeta
- grid.1013.30000 0004 1936 834XSydney School of Veterinary Science, Faculty of Science, University of Sydney, Sydney, Australia
| | - Dušan Romportl
- grid.4491.80000 0004 1937 116XDepartment of Physical Geography and Geoecology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Nicola Ferrari
- grid.4708.b0000 0004 1757 2822Department of Veterinary Medicine, Università degli Studi di Milano, Milan, Italy ,grid.4708.b0000 0004 1757 2822Research Center Epidemiology and Molecular Surveillance of Infections ‘‘EpiSoMI’’, Università degli Studi di Milano, Milan, Italy
| | | | - David Modrý
- grid.418338.50000 0001 2255 8513Institute of Parasitology, Biology Centre, The Czech Academy of Sciences, Ceske Budejovice, Czech Republic ,Department of Pathology and Parasitology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic ,grid.10267.320000 0001 2194 0956Department of Botany and Zoology, Faculty of Science, Masaryk University, Brno, Czech Republic
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21
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Colchero F, Eckardt W, Stoinski T. Evidence of demographic buffering in an endangered great ape: Social buffering on immature survival and the role of refined sex-age classes on population growth rate. J Anim Ecol 2021; 90:1701-1713. [PMID: 33759185 DOI: 10.1111/1365-2656.13486] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 03/16/2021] [Indexed: 11/29/2022]
Abstract
Theoretical and empirical research has shown that increased variability in demographic rates often results in a decline in the population growth rate. In order to reduce the adverse effects of increased variability, life-history theory predicts that demographic rates that contribute disproportionately to population growth should be buffered against environmental variation. To date, evidence of demographic buffering is still equivocal and limited to analyses on a reduced number of age classes (e.g. juveniles and adults), and on single sex models. Here we used Bayesian inference models for age-specific survival and fecundity on a long-term dataset of wild mountain gorillas. We used these estimates to parameterize two-sex, age-specific stochastic population projection models that accounted for the yearly covariation between demographic rates. We estimated the sensitivity of the long-run stochastic population growth rate to reductions in survival and fecundity on ages belonging to nine sex-age classes for survival and three age classes for female fecundity. We found a statistically significant negative linear relationship between the sensitivities and variances of demographic rates, with strong demographic buffering on young adult female survival and low buffering on older female and silverback survival and female fecundity. We found moderate buffering on all immature stages and on prime-age females. Previous research on long-lived slow species has found high buffering of prime-age female survival and low buffering on immature survival and fecundity. Our results suggest that the moderate buffering of the immature stages can be partially due to the mountain gorilla social system and the relative stability of their environment. Our results provide clear support for the demographic buffering hypothesis and its predicted effects on species at the slow end of the slow-fast life-history continuum, but with the surprising outcome of moderate social buffering on the survival of immature stages. We also demonstrate how increasing the number of sex-age classes can greatly improve the detection of demographic buffering in wild populations.
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Affiliation(s)
- Fernando Colchero
- Department of Mathematics and Computer Science, University of Southern Denmark, Odense, Denmark.,Interdisciplinary Center on Population Dynamics, University of Southern Denmark, Odense, Denmark
| | - Winnie Eckardt
- The Dian Fossey Gorilla Fund International, Atlanta, GA, USA
| | - Tara Stoinski
- The Dian Fossey Gorilla Fund International, Atlanta, GA, USA
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22
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van der Hoek Y, Binyinyi E, Ngobobo U, Stoinski TS, Caillaud D. Daily Travel Distances of Unhabituated Grauer's Gorillas (Gorilla beringei graueri) in a Low Elevation Forest. Folia Primatol (Basel) 2021; 92:112-125. [PMID: 33756464 DOI: 10.1159/000514626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 01/20/2021] [Indexed: 01/05/2023]
Abstract
To accurately determine the space use of animals, we need to follow animal movements over prolonged periods, which is especially challenging for the critically endangered Grauer's gorillas (Gorilla beringei graueri) in eastern Democratic Republic of the Congo (DRC). As a consequence, we know little about Grauer's gorillas, particularly from the lower elevational parts of their range. Between 2016 and 2018, we tracked unhabituated Grauer's gorillas in lowland forests (500-1,000 m a.s.l.), at the community-managed Nkuba Conservation Area in Nord Kivu (DRC) to provide estimates of daily travel distances (DTD), daily displacement distances (DDD), and the linearity of recorded paths expressed as the Linearity Index (LI): DDD/DTD. We found an average DTD of ∼1.3 km (range 0.05-5.0 km), with temporal variation among monthly averages; specifically, an increase in travel distance over the June-August dry season resulting in peak travel distances at the beginning of the September-December wet season. Daily displacements showed similar temporal variation, which resulted in a lack of obvious temporal patterns in LI. We conclude that the movement patterns of Grauer's gorillas in lowland forests, which are characterized by larger DTD than those of Grauer's gorillas that inhabit highland habitats, show similarity to travel distances of other predominantly frugivorous gorillas. Moreover, the observed temporal patterns in space use may be tentatively linked to temporal changes in fruit availability or consumption. These observations have consequences for our understanding of the ecological role that Grauer's gorillas play and provide baseline data to estimate current and future distributions, abundances, and carrying capacities of this highly threatened animal.
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Affiliation(s)
| | | | - Urbain Ngobobo
- The Dian Fossey Gorilla Fund International, Musanze, Rwanda
| | | | - Damien Caillaud
- Department of Anthropology, University of California, Davis, California, USA
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Sinayitutse E, Modry D, Slapeta J, Nyiramana A, Mudakikwa A, Muvunyi R, Eckardt W. Daily defecation outputs of mountain gorillas (Gorilla beringei beringei) in the Volcanoes National Park, Rwanda. Primates 2020; 62:311-320. [PMID: 33221967 DOI: 10.1007/s10329-020-00874-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 11/02/2020] [Indexed: 02/04/2023]
Abstract
Increasing population density can increase infectious disease risk and thus reduce population growth and size. Host-parasite interactions of threatened animals that remain in small protected forest fragments therefore need to be monitored carefully. Due to extreme conservation efforts, the mountain gorilla (Gorilla beringei beringei) population in the 450-km2 Virunga Massif has more than doubled since 1973, reaching 604 individuals in 2016. To better understand changes in the transmission risks of soil-borne and other enteric pathogens for mountain gorillas, we determined defecation outputs of different age-sex classes and the diurnal variation in feces deposition. We weighed 399 wet fecal samples deposited at nest sites and on trails between nest sites by gorillas of varying age and sex, determined by lobe diameter, from five social groups (n = 58 gorillas) that range in the Volcanoes National Park, Rwanda. We found increasing daily average defecation outputs with increasing age-sex class (infants, 435 g; juveniles, 1346 g; medium-sized gorillas, 2446 g; silverbacks, 3609 g). Gorillas deposited two- to threefold the amount of feces at nest sites compared to on trails, suggesting that nest sites may function as hotspots for enteric pathogen infections through direct contact or when gorillas ingest foods contaminated with infectious larvae during site revisits in intervals matching the maturation period of environmentally transmitted gastrointestinal parasites. In combination with ranging and demographic data, these findings will enable the modeling of spatiotemporal variation in soil contamination and infectious disease risk for Virunga gorillas as their population density continues to increase.
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Affiliation(s)
- Elie Sinayitutse
- The Dian Fossey Gorilla Fund International, 800 Cherokee Ave SE, Atlanta, GA, 30315, USA.
- The University of Rwanda, Butare, Huye, Rwanda.
| | - David Modry
- Department of Pathology and Parasitology, University of Veterinary and Pharmaceutical Sciences, Palackéhotřida 1946/1, 612 42, Brno, Czech Republic
- University of Veterinary and Pharmaceutical Sciences Brno, Palackéhotřida 1946/1, 612 42, Brno, Czech Republic
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, Branišovská 1160/31, 370, České Budějovice, Czech Republic
| | - Jan Slapeta
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Sydney, NSW, 2006, Australia
| | | | - Antoine Mudakikwa
- Department of Tourism and Conservation, Rwanda Development Board, Kigali, Rwanda
| | - Richard Muvunyi
- Department of Tourism and Conservation, Rwanda Development Board, Kigali, Rwanda
| | - Winnie Eckardt
- The Dian Fossey Gorilla Fund International, 800 Cherokee Ave SE, Atlanta, GA, 30315, USA
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Caillaud D, Eckardt W, Vecellio V, Ndagijimana F, Mucyo JP, Hirwa JP, Stoinski T. Violent encounters between social units hinder the growth of a high-density mountain gorilla population. SCIENCE ADVANCES 2020; 6:6/45/eaba0724. [PMID: 33148636 PMCID: PMC7673674 DOI: 10.1126/sciadv.aba0724] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 08/29/2020] [Indexed: 05/29/2023]
Abstract
Density-dependent processes such as competition for resources, migration, predation, and disease outbreaks limit the growth of natural populations. The analysis of 50 years of mountain gorilla data reveals that social behavior changes observed at high group density may also affect population growth in social species. A sudden increase in social group density observed in 2007 caused a threefold increase in the rate of violent encounters between social units (groups and solitary males). A fivefold increase in the rate of infanticide and seven cases of lethal fights among mature males were subsequently recorded, and the annual subpopulation growth rate declined by half between 2000 and 2017. The increase in infanticide alone explains 57% of this decline. These findings highlight the complex relationship between population density and growth in social species and hold important implications for the management of island populations.
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Affiliation(s)
- Damien Caillaud
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA.
- Department of Anthropology, University of California, Davis, One Shields Ave., Davis, CA 95616, USA
| | - Winnie Eckardt
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Veronica Vecellio
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Felix Ndagijimana
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Jean-Pierre Mucyo
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Jean-Paul Hirwa
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA
| | - Tara Stoinski
- The Dian Fossey Gorilla Fund, 800 Cherokee Ave. SE, Atlanta, GA 30315, USA.
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Morrison RE, Hirwa JP, Mucyo JPS, Stoinski TS, Vecellio V, Eckardt W. Inter‐group relationships influence territorial defence in mountain gorillas. J Anim Ecol 2020; 89:2852-2862. [DOI: 10.1111/1365-2656.13355] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/06/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Robin E. Morrison
- The Dian Fossey Gorilla Fund Musanze Rwanda
- Centre for Research in Animal Behaviour University of Exeter Exeter UK
| | | | | | - Tara S. Stoinski
- The Dian Fossey Gorilla Fund Musanze Rwanda
- The Dian Fossey Gorilla Fund Atlanta GA USA
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Harper CM, Ruff CB, Sylvester AD. Gorilla calcaneal morphological variation and ecological divergence. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 174:49-65. [PMID: 32871028 DOI: 10.1002/ajpa.24135] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 06/11/2020] [Accepted: 08/02/2020] [Indexed: 01/19/2023]
Abstract
OBJECTIVES The primate foot has been extensively investigated because of its role in weight-bearing; however, the calcaneus has been relatively understudied. Here we examine entire gorilla calcaneal external shape to understand its relationship with locomotor behavior. MATERIALS AND METHODS Calcanei of Gorilla gorilla gorilla (n = 43), Gorilla beringei graueri (n = 20), and Gorilla beringei beringei (n = 15) were surface or micro-CT scanned. External shape was analyzed through a three-dimensional geometric morphometric sliding semilandmark analysis. Semilandmarks were slid relative to an updated Procrustes average in order to minimize the bending energy of the thin plate spline interpolation function. Shape variation was summarized using principal components analysis of shape coordinates. Procrustes distances between taxa averages were calculated and resampling statistics run to test pairwise differences. Linear measures were collected and regressed against estimated body mass. RESULTS All three taxa exhibit statistically different morphologies (p < .001 for pairwise comparisons). G. g. gorilla demonstrates an anteroposteriorly elongated calcaneus with a deeper cuboid pivot region and mediolaterally flatter posterior talar facet. G. b. beringei possesses the flattest cuboid and most medially-angled posterior talar facets. G. b. graueri demonstrates intermediate articular facet morphology, a medially-angled tuberosity, and an elongated peroneal trochlea. DISCUSSION Articular facet differences separate gorillas along a locomotor gradient. G. g. gorilla is adapted for arboreality with greater joint mobility, while G. b. beringei is adapted for more stereotypical loads associated with terrestriality. G. b. graueri's unique posterolateral morphology may be due to a secondary transition to greater arboreality from a more terrestrial ancestor.
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Affiliation(s)
- Christine M Harper
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christopher B Ruff
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Adam D Sylvester
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Seiler N, Robbins MM. Using long-term ranging patterns to assess within-group and between-group competition in wild mountain gorillas. BMC Ecol 2020; 20:40. [PMID: 32677937 PMCID: PMC7367404 DOI: 10.1186/s12898-020-00306-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 06/30/2020] [Indexed: 11/28/2022] Open
Abstract
Background Competition within and between social groups determines access to resources and can be inferred from space use parameters that reflect depletion of food resources and competitive abilities of groups. Using location data from 1998 to 2017, we investigated within- and between-group competition in 12 groups of wild mountain gorillas (Gorilla beringei beringei). As within-group feeding competition is expected to increase with group size, an increase in group size is predicted to lead to an increase in the size of annual home ranges and core areas, but to a decrease in fidelity (reuse of an area). Due to asymmetries in competitive abilities, larger groups are expected to have higher exclusivity (degree of non-shared space) of annual home ranges and core areas than smaller groups. Results We found evidence of within-group feeding competition based on a positive relationship between group size and both annual home range and core area size as well as a negative relationship between group size and core area fidelity. Additionally, fidelity of core areas was lower than of home ranges. Between-group competition was inferred from a trend for groups with more members and more males to have more exclusive home ranges and core areas. Lastly, annual core areas were largely mutually exclusive. Conclusions Our study suggests that non-territorial, group-living animals can have highly dynamic, long-term avoidance-based spacing patterns, both temporally and spatially, to maintain annual core area exclusivity among groups while concurrently shifting these areas annually within overlapping home ranges to avoid resource depletion. Despite ranging in larger home ranges and core areas, larger groups were able to maintain more exclusive ranges than smaller groups, suggesting a competitive advantage for larger groups in between-group competition in a non-territorial species. Together, these findings contribute to understanding how social animals make behavioral adjustments to mitigate the effects of intraspecific competition.
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Affiliation(s)
- Nicole Seiler
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany.
| | - Martha M Robbins
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103, Leipzig, Germany
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Seiler N, Robbins MM. Ecological correlates of space use patterns in wild western lowland gorillas. Am J Primatol 2020; 82:e23168. [DOI: 10.1002/ajp.23168] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 06/16/2020] [Accepted: 06/20/2020] [Indexed: 12/31/2022]
Affiliation(s)
- Nicole Seiler
- Department of Primatology Max Planck Institute for Evolutionary Anthropology Leipzig Germany
| | - Martha M. Robbins
- Department of Primatology Max Planck Institute for Evolutionary Anthropology Leipzig Germany
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Cooksey K, Sanz C, Ebombi TF, Massamba JM, Teberd P, Magema E, Abea G, Peralejo JSO, Kienast I, Stephens C, Morgan D. Socioecological Factors Influencing Intergroup Encounters in Western Lowland Gorillas (Gorilla gorilla gorilla). INT J PRIMATOL 2020. [DOI: 10.1007/s10764-020-00147-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
The evolutionary origins of how modern humans share and use space are often modelled on the territorial-based violence of chimpanzees, with limited comparison to other apes. Gorillas are widely assumed to be non-territorial due to their large home ranges, extensive range overlap, and limited inter-group aggression. Using large-scale camera trapping, we monitored western gorillas in Republic of Congo across 60 km2. Avoidance patterns between groups were consistent with an understanding of the “ownership” of specific regions, with greater avoidance of their neighbours the closer they were to their neighbours’ home range centres. Groups also avoided larger groups’ home ranges to a greater extent, consistent with stronger defensive responses from more dominant groups. Our results suggest that groups may show territoriality, defending core regions of their home ranges against neighbours, and mirror patterns common across human evolution, with core areas of resident dominance and larger zones of mutual tolerance. This implies western gorillas may be a key system for understanding how humans have evolved the capacity for extreme territorial-based violence and warfare, whilst also engaging in the strong affiliative inter-group relationships necessary for large-scale cooperation.
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Furuichi T. Variation in Intergroup Relationships Among Species and Among and Within Local Populations of African Apes. INT J PRIMATOL 2020. [DOI: 10.1007/s10764-020-00134-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Salmi R, Presotto A, Scarry CJ, Hawman P, Doran-Sheehy DM. Spatial cognition in western gorillas (Gorilla gorilla): an analysis of distance, linearity, and speed of travel routes. Anim Cogn 2020; 23:545-557. [PMID: 32060749 DOI: 10.1007/s10071-020-01358-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/27/2020] [Accepted: 01/31/2020] [Indexed: 01/04/2023]
Abstract
Spatial memory allows animals to retain information regarding the location, distribution, and quality of feeding sites to optimize foraging decisions. Western gorillas inhabit a complex environment with spatiotemporal fluctuations of resource availability, prefer fruits when available, and travel long distances to reach them. Here, we examined movement patterns-such as linearity, distance, and speed of traveling-to assess whether gorillas optimize travel when reaching out-of-sight valued resources. Our results show that gorillas travel patterns are affected by the activity they perform next, the type of food they feed on, and their preference level to specific fruits, suggesting they are able to optimize foraging based on spatial knowledge of their resources. Additionally, gorillas left in the direction of the next resource as soon as they started traveling and decelerated before approaching food resources, as evidence that they have a representation of their exact locations. Moreover, home range familiarity did not influence gorillas' movement patterns, as travel linearity in the core and periphery did not differ, suggesting that they may not depend wholly on a network of paths to navigate their habitat. These results show some overlap with chimpanzees' spatial abilities. Differences between the two ape species exist, however, potentially reflecting more their differences in diet (degree of frugivory) rather than their cognitive abilities. Further studies should focus on determining whether gorillas are able to use shortcuts and/or approach the same goal from multiple directions to better identify the spatial abilities used by this species.
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Affiliation(s)
- Roberta Salmi
- Department of Anthropology, University of Georgia, Athens, GA, 30602, USA. .,Department of Geography, Center for Geospatial Research, University of Georgia, Athens, GA, USA.
| | - Andrea Presotto
- Department of Geography and Geosciences, Salisbury University, Salisbury, MD, USA
| | - Clara J Scarry
- Department of Anthropology, California State University, Sacramento, Sacramento, CA, USA
| | - Peter Hawman
- Department of Geography, Center for Geospatial Research, University of Georgia, Athens, GA, USA
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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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34
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Fatica LM, Almécija S, McFarlin SC, Hammond AS. Pelvic shape variation among gorilla subspecies: Phylogenetic and ecological signals. J Hum Evol 2019; 137:102684. [DOI: 10.1016/j.jhevol.2019.102684] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 01/28/2023]
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Lodwick JL, Salmi R. Nutritional composition of the diet of the western gorilla (Gorilla gorilla): Interspecific variation in diet quality. Am J Primatol 2019; 81:e23044. [PMID: 31463957 DOI: 10.1002/ajp.23044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 08/02/2019] [Accepted: 08/13/2019] [Indexed: 12/15/2022]
Abstract
To meet nutritional needs, primates adjust their diets in response to local habitat differences, though whether these dietary modifications translate to changes in dietary nutrient intake is unknown. A previous study of two populations of the mountain gorilla (MG: Gorilla beringei) found no evidence for intraspecific variation in the nutrient composition of their diets, despite ecological and dietary differences between sites. One potential explanation is that nutritional variability in primate diets requires greater ecological divergence than what was captured between MG sites, underpinning environmental differences in the nutrient quality of plant foods. To test whether Gorilla exhibits interspecific variation in dietary composition and nutrient intake, we studied the composition and macronutrients of the western gorilla (WG: Gorilla gorilla) staple diets and compared them with published data from the two MG populations. We recorded feeding time and food intake of four adult female WGs from one habituated group over a period of 11 months (December 2004-October 2005) at the Mondika Research Center, Republic of Congo, allowing for assessment of seasonal patterns of nutrient intake. Staple diets of WGs and MGs diverged in their dietary and macronutrient composition. Compared to MGs, the staple diet of WGs (by intake) contained higher proportions of fruit (43%) and leaf (12%) and a lower proportion of herb (39%), resulting in a higher intake of total nonstructural carbohydrate and fiber and a lower intake of crude protein. Staple gorilla fruits and herbs differed in nutrient quality between sites. Gorillas exhibit nutritional flexibility that reflects ecological variation in the nutrient quality of plant foods. Since dietary quality typically affects rates of growth and reproduction in primates, our results suggest that interspecific differences in nutrient intake and food quality may shape differences in gorilla nutrient balancing and female life history strategies.
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Affiliation(s)
- Jessica L Lodwick
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, New York.,Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut
| | - Roberta Salmi
- Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, New York.,Department of Anthropology, University of Georgia, Athens, Georgia
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36
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Pisor AC, Surbeck M. The evolution of intergroup tolerance in nonhuman primates and humans. Evol Anthropol 2019; 28:210-223. [DOI: 10.1002/evan.21793] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 04/05/2019] [Accepted: 07/05/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Anne C. Pisor
- Department of AnthropologyWashington State University Pullman Washington
- Department of Human Behavior, Ecology, and CultureMax Planck Institute for Evolutionary Anthropology Leipzig Germany
| | - Martin Surbeck
- Department of Human Evolutionary BiologyHarvard University Cambridge Massachusetts
- Department of PrimatologyMax Planck Institute for Evolutionary Anthropology Leipzig Germany
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Eckardt W, Stoinski TS, Rosenbaum S, Santymire R. Social and ecological factors alter stress physiology of Virunga mountain gorillas ( Gorilla beringei beringei). Ecol Evol 2019; 9:5248-5259. [PMID: 31110676 PMCID: PMC6509442 DOI: 10.1002/ece3.5115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 02/05/2019] [Accepted: 03/01/2019] [Indexed: 11/12/2022] Open
Abstract
Living in a rapidly changing environment can alter stress physiology at the population level, with negative impacts on health, reproductive rates, and mortality that may ultimately result in species decline. Small, isolated animal populations where genetic diversity is low are at particular risks, such as endangered Virunga mountain gorillas (Gorilla beringei beringei). Along with climate change-associated environmental shifts that are affecting the entire population, subpopulations of the Virunga gorillas have recently experienced extreme changes in their social environment. As the growing population moves closer to the forest's carrying capacity, the gorillas are coping with rising population density, increased frequencies of interactions between social units, and changing habitat use (e.g., more overlapping home ranges and routine ranging at higher elevations). Using noninvasive monitoring of fecal glucocorticoid metabolites (FGM) on 115 habituated Virunga gorillas, we investigated how social and ecological variation are related to baseline FGM levels, to better understand the adaptive capacity of mountain gorillas and monitor potential physiological indicators of population decline risks. Generalized linear mixed models revealed elevated mean monthly baseline FGM levels in months with higher rainfall and higher mean maximum and minimum temperature, suggesting that Virunga gorillas might be sensitive to predicted warming and rainfall trends involving longer, warmer dry seasons and more concentrated and extreme rainfall occurrences. Exclusive use of smaller home range areas was linked to elevated baseline FGM levels, which may reflect reduced feeding efficiency and increased travel efforts to actively avoid neighboring groups. The potential for additive effects of stress-inducing factors could have short- and long-term impacts on the reproduction, health, and ultimately survival of the Virunga gorilla population. The ongoing effects of environmental changes and population dynamics must be closely monitored and used to develop effective long-term conservation strategies that can help address these risk factors.
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Affiliation(s)
| | | | - Stacy Rosenbaum
- Departmet of AnthropologyNorthwestern UniversityEvanstonIllinois
- Davee Center for Epidemiology and EndocrinologyLincoln Park ZooChicagoIllinois
| | - Rachel Santymire
- Davee Center for Epidemiology and EndocrinologyLincoln Park ZooChicagoIllinois
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39
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Porter A, Eckardt W, Vecellio V, Guschanski K, Niehoff PP, Ngobobo-As-Ibungu U, Nishuli Pekeyake R, Stoinski T, Caillaud D. Behavioral responses around conspecific corpses in adult eastern gorillas ( Gorilla beringei spp.). PeerJ 2019; 7:e6655. [PMID: 30972250 PMCID: PMC6450378 DOI: 10.7717/peerj.6655] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 02/20/2019] [Indexed: 11/20/2022] Open
Abstract
Humans were once considered unique in having a concept of death but a growing number of observations of animal responses to dying and dead conspecifics suggests otherwise. Complex arrays of behaviors have been described ranging from corpse removal and burial among social insects to quiet attendance and caregiving among elephants and primates. Less frequently described, however, are behavioral responses of individuals from different age/sex classes or social position toward the death of conspecifics. We describe behavioral responses of mountain gorillas (Gorilla beringei beringei) to the deaths of a dominant silverback and a dominant adult female from the same social group in Volcanoes National Park in Rwanda and the responses of Grauer’s gorillas (Gorilla b. graueri) to the corpse of an extra-group silverback in Kahuzi-Biega National Park, Democratic Republic of Congo. In gorillas, interactions between groups or with a lone silverback often result in avoidance or aggression. We predicted that: (i) more individuals should interact with the corpses of same-group members than with the corpse of the extra-group silverback; (ii) adult females with infants should avoid the corpse of the extra-group silverback; and (iii) in the mountain gorilla cases, individuals that shared close social relationships with the dead individual should spend more time with the corpse than other individuals in the group. We used a combination of detailed qualitative reports, photos, and videos to describe all occurrences of affiliative/investigative and agonistic behaviors observed at the corpses. We observed similar responses toward the corpses of group and extra-group individuals. Animals in all three cases showed a variety of affiliative/investigative and agonistic behaviors directed to the corpses. Animals of all age/sex classes interacted with the corpses in affiliative/investigative ways but there was a notable absence of all adult females at the corpse of the extra-group silverback. In all three cases, we observed only silverbacks and blackbacks being agonistic around and/or toward the corpses. In the mountain gorilla cases, the individuals who spent the most time with the corpses were animals who shared close social relationships with the deceased. We emphasize the similarity in the behavioral responses around the corpses of group and extra-group individuals, and suggest that the behavioral responses were influenced in part by close social relationships between the deceased and certain group members and by a general curiosity about death. We further discuss the implications close interactions with corpses have for disease transmission within and between gorilla social groups.
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Affiliation(s)
- Amy Porter
- The Dian Fossey Gorilla Fund International, Atlanta, GA, United States of America
| | - Winnie Eckardt
- The Dian Fossey Gorilla Fund International, Atlanta, GA, United States of America
| | - Veronica Vecellio
- The Dian Fossey Gorilla Fund International, Atlanta, GA, United States of America
| | - Katerina Guschanski
- Animal Ecology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala Universitet, Uppsala, Sweden
| | - Peter Philip Niehoff
- Animal Ecology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala Universitet, Uppsala, Sweden
| | | | - Radar Nishuli Pekeyake
- Institut Congolais pour la Conservation de la Nature, Kinshasa, Democratic Republic of Congo
| | - Tara Stoinski
- The Dian Fossey Gorilla Fund International, Atlanta, GA, United States of America
| | - Damien Caillaud
- The Dian Fossey Gorilla Fund International, Atlanta, GA, United States of America.,Department of Anthropology, University of California, Davis, Davis, CA, United States of America
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Fan PL, Li YM, Stanford CB, Li F, Liu ZT, Yang KH, Liu XC. Home range variation of two different-sized groups of golden snub-nosed monkeys ( Rhinopithecus roxellana) in Shennongjia, China: implications for feeding competition. Zool Res 2019; 40:121-128. [PMID: 29955030 PMCID: PMC6378561 DOI: 10.24272/j.issn.2095-8137.2018.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Knowledge on the home range size of a species or population is important for understanding its behavioral and social ecology and improving the effectiveness of conservation strategies. We studied the home range size of two different-sized groups of golden snub-nosed monkeys (Rhinopithecus roxellana) in Shennongjia, China. The larger group (236 individuals) had a home range of 22.5 km2 from September 2007 to July 2008, whereas the smaller group (62 individuals) occupied a home range of 12.4 km2 from November 2008 to July 2009. Both groups exhibited considerable seasonal variation in their home range size, which was likely due to seasonal changes in food availability and distribution. The home range in any given season (winter, spring, summer, or winter+spring+summer) of the larger group was larger than that of the smaller group. As the two groups were studied in the same area, with the confounding effects of food availability thus minimized, the positive relationship between home range size and group size suggested that scramble feeding competition increased within the larger group.
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Affiliation(s)
- Peng-Lai Fan
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.,Institute of Ecology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Yi-Ming Li
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Craig B Stanford
- Departments of Biological Sciences and Anthropology, Jane Goodall Research Center, University of Southern California, Los Angeles, California 90089, USA
| | - Fang Li
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ze-Tian Liu
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Kai-Hua Yang
- Shennongjia National Park, Shennongjia Hubei 442421, China
| | - Xue-Cong Liu
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; E-mail:
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Grueter CC, Robbins AM, Abavandimwe D, Vecellio V, Ndagijimana F, Stoinski TS, Robbins MM. Quadratic relationships between group size and foraging efficiency in a herbivorous primate. Sci Rep 2018; 8:16718. [PMID: 30425319 PMCID: PMC6233200 DOI: 10.1038/s41598-018-35255-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/18/2018] [Indexed: 11/23/2022] Open
Abstract
The effect of feeding competition on foraging efficiency is an important link between ecological factors and the social organization of gregarious species. We examined the effects of group size on daily travel distances, activity budgets, and energy intake of mountain gorillas in Rwanda. We measured daily travel distances of five groups, activity budgets of 79 gorillas in nine groups, and energy intake data for 23 adult females in three groups over a 16-month period. Travel distances and the proportion of time spent traveling increased with size for most groups, which would be expected if their foraging efficiency is limited by intragroup feeding competition. However, travel distances and times decreased for the largest group, which also had higher energy intake rates than intermediate sized groups. The improved foraging efficiency of the largest group may be explained by advantages in intergroup contest competition. The largest group had much lower home range overlap than the other study groups which may be due to groups avoiding one another as a result of male mating competition. Collectively, our results indicate that intermediate sized groups had the lowest foraging efficiency and provide a new twist on the growing evidence of non-linear relationships between group size and foraging efficiency in primates.
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Affiliation(s)
- Cyril C Grueter
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
- The Dian Fossey Gorilla Fund International, Atlanta, USA.
- School of Human Sciences, The University of Western Australia, Perth, Australia.
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Perth, Australia.
| | - Andrew M Robbins
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | | | | | | | - Tara S Stoinski
- The Dian Fossey Gorilla Fund International, Atlanta, USA
- Zoo Atlanta, Atlanta, USA
| | - Martha M Robbins
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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42
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Mirville MO, Ridley AR, Samedi JPM, Vecellio V, Ndagijimana F, Stoinski TS, Grueter CC. Low familiarity and similar ‘group strength’ between opponents increase the intensity of intergroup interactions in mountain gorillas (Gorilla beringei beringei). Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2592-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Robbins MM, Robbins AM. Variation in the social organization of gorillas: Life history and socioecological perspectives. Evol Anthropol 2018; 27:218-233. [PMID: 30325554 DOI: 10.1002/evan.21721] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 07/18/2018] [Accepted: 08/06/2018] [Indexed: 01/29/2023]
Abstract
A focus of socioecological research is to understand how ecological, social, and life history factors influence the variability of social organization within and between species. The genus Gorilla exhibits variability in social organization with western gorilla groups being almost exclusively one-male, yet approximately 40% of mountain gorilla groups are multimale. We review five ultimate causes for the variability in social organization within and among gorilla populations: human disturbance, ecological constraints on group size, risk of infanticide, life history patterns, and population density. We find the most evidence for the ecological constraints and life history hypotheses, but an over-riding explanation remains elusive. The variability may hinge on variation in female dispersal patterns, as females seek a group of optimal size and with a good protector male. Our review illustrates the challenges of understanding why the social organization of closely related species may deviate from predictions based on socioecological and life history theory.
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Affiliation(s)
- Martha M Robbins
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Andrew M Robbins
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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44
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Mirville MO, Ridley AR, Samedi J, Vecellio V, Ndagijimana F, Stoinski TS, Grueter CC. Factors influencing individual participation during intergroup interactions in mountain gorillas. Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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45
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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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46
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Grueter CC, Wright E, Abavandimwe D, Ortmann S, Mudakikwa A, Musana A, Uwingeli P, Ndagijimana F, Vecellio V, Stoinski TS, Robbins MM. Going to extremes for sodium acquisition: use of community land and high-altitude areas by mountain gorillas Gorilla beringei
in Rwanda. Biotropica 2018. [DOI: 10.1111/btp.12598] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Cyril C. Grueter
- School of Human Sciences; The University of Western Australia; Perth WA 6009 Australia
- Centre for Evolutionary Biology; School of Biological Sciences; The University of Western Australia; Perth WA 6009 Australia
- Max Planck Institute for Evolutionary Anthropology; Deutscher Platz 6 04103 Leipzig Germany
- The Dian Fossey Gorilla Fund International; 800 Cherokee Avenue SE Atlanta GA 30315 USA
| | - Edward Wright
- Max Planck Institute for Evolutionary Anthropology; Deutscher Platz 6 04103 Leipzig Germany
| | - Didier Abavandimwe
- The Dian Fossey Gorilla Fund International; 800 Cherokee Avenue SE Atlanta GA 30315 USA
| | - Sylvia Ortmann
- Department of Evolutionary Ecology; Leibniz Institute for Zoo and Wildlife Research; Alfred-Kowalke-Straße 17 10315 Berlin Germany
| | - Antoine Mudakikwa
- Tourism and Conservation; Rwanda Development Board (RDB); P.O. Box 6239 Kigali Rwanda
| | - Abel Musana
- Tourism and Conservation; Rwanda Development Board (RDB); P.O. Box 6239 Kigali Rwanda
| | - Propser Uwingeli
- Tourism and Conservation; Rwanda Development Board (RDB); P.O. Box 6239 Kigali Rwanda
| | - Felix Ndagijimana
- The Dian Fossey Gorilla Fund International; 800 Cherokee Avenue SE Atlanta GA 30315 USA
| | - Veronica Vecellio
- The Dian Fossey Gorilla Fund International; 800 Cherokee Avenue SE Atlanta GA 30315 USA
| | - Tara S. Stoinski
- The Dian Fossey Gorilla Fund International; 800 Cherokee Avenue SE Atlanta GA 30315 USA
| | - Martha M. Robbins
- Max Planck Institute for Evolutionary Anthropology; Deutscher Platz 6 04103 Leipzig Germany
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Seiler N, Boesch C, Stephens C, Ortmann S, Mundry R, Robbins MM. Social and ecological correlates of space use patterns in Bwindi mountain gorillas. Am J Primatol 2018; 80:e22754. [DOI: 10.1002/ajp.22754] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 02/27/2018] [Accepted: 03/08/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Nicole Seiler
- Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
| | | | - Colleen Stephens
- Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
| | - Sylvia Ortmann
- Leibniz Institute for Zoo and Wildlife Research; Berlin Germany
| | - Roger Mundry
- Max Planck Institute for Evolutionary Anthropology; Leipzig Germany
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Ruff CB, Burgess ML, Junno J, Mudakikwa A, Zollikofer CPE, Ponce de León MS, McFarlin SC. Phylogenetic and environmental effects on limb bone structure in gorillas. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:353-372. [DOI: 10.1002/ajpa.23437] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 01/29/2018] [Accepted: 01/30/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Christopher B. Ruff
- Johns Hopkins University School of MedicineCenter for Functional Anatomy and Evolution, 1830 E. Monument StBaltimore Maryland 21205
| | - M. Loring Burgess
- Johns Hopkins University School of MedicineCenter for Functional Anatomy and Evolution, 1830 E. Monument StBaltimore Maryland 21205
| | | | - Antoine Mudakikwa
- Department of Tourism and ConservationRwanda Development BoardKigali Rwanda
| | | | | | - Shannon C. McFarlin
- Department of Anthropology, Center for the Advanced Study of Human PaleobiologyThe George Washington UniversityWashington DC
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Thompson NE, Ostrofsky KR, McFarlin SC, Robbins MM, Stoinski TS, Almécija S. Unexpected terrestrial hand posture diversity in wild mountain gorillas. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:84-94. [PMID: 29344933 DOI: 10.1002/ajpa.23404] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 01/18/2023]
Abstract
OBJECTIVES Gorillas, along with chimpanzees and bonobos, are ubiquitously described as 'knuckle-walkers.' Consequently, knuckle-walking (KW) has been featured pre-eminently in hypotheses of the pre-bipedal locomotor behavior of hominins and in the evolution of locomotor behavior in apes. However, anecdotal and behavioral accounts suggest that mountain gorillas may utilize a more complex repertoire of hand postures, which could alter current interpretations of African ape locomotion and its role in the emergence of human bipedalism. Here we documented hand postures during terrestrial locomotion in wild mountain gorillas to investigate the frequency with which KW and other hand postures are utilized in the wild. MATERIALS AND METHODS Multiple high-speed cameras were used to record bouts of terrestrial locomotion of 77 habituated mountain gorillas at Bwindi Impenetrable National Park (Uganda) and Volcanoes National Park (Rwanda). RESULTS We captured high-speed video of hand contacts in 8% of the world's population of mountain gorillas. Our results reveal that nearly 40% of these gorillas used "non-KW" hand postures, and these hand postures constituted 15% of all hand contacts. Some of these "non-KW" hand postures have never been documented in gorillas, yet match hand postures previously identified in orangutans. DISCUSSION These results highlight a previously unrecognized level of hand postural diversity in gorillas, and perhaps great apes generally. Although present at lower frequencies than KW, we suggest that the possession of multiple, versatile hand postures present in wild mountain gorillas may represent a shared feature of the African ape and human clade (or even great ape clade) rather than KW per se.
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Affiliation(s)
- Nathan E Thompson
- Department of Anatomy, NYIT College of Osteopathic Medicine, Northern Boulevard, Old Westbury, New York
| | - Kelly R Ostrofsky
- Center for the Advanced Study of Human Paleobiology, The George Washington University, 800 22nd St. NW, Suite 6000, Washington, DC
| | - Shannon C McFarlin
- Center for the Advanced Study of Human Paleobiology, The George Washington University, 800 22nd St. NW, Suite 6000, Washington, DC
| | - Martha M Robbins
- Department of Primatology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, Leipzig, 04103, Germany
| | - Tara S Stoinski
- Dian Fossey Gorilla Fund International, 800 Cherokee Avenue SE, Atlanta, Georgia
| | - Sergio Almécija
- Center for the Advanced Study of Human Paleobiology, The George Washington University, 800 22nd St. NW, Suite 6000, Washington, DC.,Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, 08193, Spain
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50
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Seiler N, Boesch C, Mundry R, Stephens C, Robbins MM. Space partitioning in wild, non-territorial mountain gorillas: the impact of food and neighbours. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170720. [PMID: 29291062 PMCID: PMC5717636 DOI: 10.1098/rsos.170720] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/27/2017] [Indexed: 06/01/2023]
Abstract
In territorial species, the distribution of neighbours and food abundance play a crucial role in space use patterns but less is known about how and when neighbours use shared areas in non-territorial species. We investigated space partitioning in 10 groups of wild, non-territorial mountain gorillas (Gorilla beringei beringei). Using location data, we examined factors influencing daily movement decisions and calculated the per cent overlap of annual kernel home ranges and core areas among neighbours. We found that the probability that a group chose an area was positively influenced by both food availability and the previous use of that area by the group. Additionally, groups reduced their overall utilization of areas previously used by neighbouring groups. Lastly, groups used their core areas more exclusively than their home ranges. In sum, our results show that both foraging needs and avoidance of competition with neighbours determined the gorillas' daily movement decisions, which presumably lead to largely mutually exclusive core areas. Our research suggests that non-territorial species actively avoid neighbours to maintain core area exclusivity. Together, these findings contribute to our understanding of the costs and benefits of non-territoriality.
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Affiliation(s)
- Nicole Seiler
- Department of Primatology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Christophe Boesch
- Department of Primatology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Roger Mundry
- Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Colleen Stephens
- Department of Primatology, Deutscher Platz 6, 04103 Leipzig, Germany
| | - Martha M. Robbins
- Department of Primatology, Deutscher Platz 6, 04103 Leipzig, Germany
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