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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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Robbins MM, Akantorana M, Arinaitwe J, Breuer T, Manguette M, McFarlin S, Meder A, Parnell R, Richardson JL, Stephan C, Stokes EJ, Stoinski TS, Vecellio V, Robbins AM. Comparative life history patterns of female gorillas. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023; 181:564-574. [PMID: 37345324 DOI: 10.1002/ajpa.24792] [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: 10/20/2022] [Revised: 03/16/2023] [Accepted: 05/24/2023] [Indexed: 06/23/2023]
Abstract
OBJECTIVES Several theories have been proposed to explain the impact of ecological conditions on differences in life history variables within and between species. Here we compare female life history parameters of one western lowland gorilla population (Gorilla gorilla gorilla) and two mountain gorilla populations (Gorilla beringei beringei). MATERIALS AND METHODS We compared the age of natal dispersal, age of first birth, interbirth interval, and birth rates using long-term demographic datasets from Mbeli Bai (western gorillas), Bwindi Impenetrable National Park and the Virunga Massif (mountain gorillas). RESULTS The Mbeli western gorillas had the latest age at first birth, longest interbirth interval, and slowest surviving birth rate compared to the Virunga mountain gorillas. Bwindi mountain gorillas were intermediate in their life history patterns. DISCUSSION These patterns are consistent with differences in feeding ecology across sites. However, it is not possible to determine the evolutionary mechanisms responsible for these differences, whether a consequence of genetic adaptation to fluctuating food supplies ("ecological risk aversion hypothesis") or phenotypic plasticity in response to the abundance of food ("energy balance hypothesis"). Our results do not seem consistent with the extrinsic mortality risks at each site, but current conditions for mountain gorillas are unlikely to match their evolutionary history. Not all traits fell along the expected fast-slow continuum, which illustrates that they can vary independently from each other ("modularity model"). Thus, the life history traits of each gorilla population may reflect a complex interplay of multiple ecological influences that are operating through both genetic adaptations and phenotypic plasticity.
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Affiliation(s)
- Martha M Robbins
- Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Moses Akantorana
- Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | | | - Thomas Breuer
- Mbeli Bai Study, Wildlife Conservation Society Congo Program, Brazzaville, Democratic Republic of the Congo
- World Wide Fund for Nature, Berlin, Germany
| | - Marie Manguette
- Mbeli Bai Study, Wildlife Conservation Society Congo Program, Brazzaville, Democratic Republic of the Congo
| | - Shannon McFarlin
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, USA
| | - Angela Meder
- Berggorilla Regenwald Direkthilfe, Hoevelhof, Germany
| | - Richard Parnell
- Mbeli Bai Study, Wildlife Conservation Society Congo Program, Brazzaville, Democratic Republic of the Congo
| | - Jack L Richardson
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, USA
| | - Claudia Stephan
- Mbeli Bai Study, Wildlife Conservation Society Congo Program, Brazzaville, Democratic Republic of the Congo
- Nouabalé-Ndoki Foundation, Brazzaville, Democratic Republic of the Congo
| | - Emma J Stokes
- Mbeli Bai Study, Wildlife Conservation Society Congo Program, Brazzaville, Democratic Republic of the Congo
| | - Tara S Stoinski
- Dian Fossey Gorilla Fund International, Atlanta, Georgia, USA
| | | | - Andrew M Robbins
- Department of Primate Behavior and Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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Sarringhaus L, Lewton KL, Iqbal S, Carlson KJ. Ape femoral-humeral rigidities and arboreal locomotion. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 179:624-639. [PMID: 36790629 PMCID: PMC9828227 DOI: 10.1002/ajpa.24632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 06/29/2022] [Accepted: 09/13/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVES This study investigates patterns of bone functional adaptations in extant apes through comparing hindlimb to forelimb bone rigidity ratios in groups with varying levels of arboreality. MATERIALS AND METHODS Using CT scans, bone rigidity (J) was calculated at three regions of interest (ROI) along femoral and humeral diaphyses in Homo, Pongo, Pan, and Gorilla with further comparisons made between species and subspecies divisions within Pan and Gorilla. RESULTS Consistent with previous work on extant hominoids, species exhibited differences in midshaft femoral to humeral (F/H) rigidity ratios. Results of the present study confirm that these midshaft differences extend to 35% and 65% diaphyseal ROIs. Modern humans, exhibiting larger ratios, and orangutans, exhibiting smaller ratios, bracketed the intermediate African apes in comparisons. Within some African apes, limb rigidity ratios varied significantly between taxonomic groups. Eastern gorillas exhibited the highest mean ratios and chimpanzees the lowest at all three ROIs. In posthoc comparisons, chimpanzees and bonobos did not differ in relative limb rigidity ratios at any of the three ROIs. However, western gorillas were more similar to bonobos than eastern gorillas at 50% and 35% ROIs, but not at the 65% ROI. CONCLUSION Species, and to a lesser extent subspecies, can be distinguished by F/H limb rigidity ratios according to broad positional behavior patterns at multiple regions of interest along the diaphyses. Similarity of bonobos and western gorillas is in line with behavioral data of bonobos being the most terrestrial of Pan species, and western gorillas the most arboreal of the Gorilla groups.
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Affiliation(s)
- Lauren Sarringhaus
- Department of Evolutionary AnthropologyDuke UniversityDurhamNorth CarolinaUSA,Department of AnthropologyUniversity of MichiganAnn ArborMichiganUSA,Department of BiologyJames Madison UniversityHarrisonburgVirginiaUSA
| | - Kristi L. Lewton
- Department of Integrative Anatomical Sciences, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Safiyyah Iqbal
- School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
| | - Kristian J. Carlson
- Department of Integrative Anatomical Sciences, Keck School of MedicineUniversity of Southern CaliforniaLos AngelesCaliforniaUSA,Evolutionary Studies InstituteUniversity of the WitwatersrandJohannesburgSouth Africa
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Geographic, climatic, and phylogenetic drivers of variation in colobine activity budgets. Primates 2022; 63:647-658. [PMID: 36083406 DOI: 10.1007/s10329-022-01015-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/26/2022] [Indexed: 10/14/2022]
Abstract
Folivorous primates are typically considered time minimizers because the constraints of their unique digestive systems require them to spend a large portion of their activity budgets resting. However, inter- and intraspecific behavioral variation in their activity budgets may be influenced by local geographic and climatic conditions and evolutionary history. We compiled 48 studies representing ten genera, 31 species, and 50 populations to assess geographic (elevation, latitude), climatic (precipitation, temperature), and phylogenetic correlates of colobine activity budgets. Time spent resting negatively correlated with time spent feeding, moving, and socializing. Except for time spent socializing, activity budgets were independent of phylogeny, with more time spent feeding and less time resting in higher-elevation habitats and at lower temperatures. Among the four most common genera in our sample, only in Rhinopithecus did time spent feeding increase with higher elevations (range, 950-3950 m above mean sea level) and lower temperatures (range, 0.9-25 ℃). Only in Trachypithecus did time spent resting decrease with lower temperatures (range, 19-25 ℃). Our findings suggest that there are no apparent effects of geographic or climatic gradients on colobine activity budgets except for Rhinopithecus and Trachypithecus, whose activities are biased in favor of energy maximization rather than time minimization. Compared with other colobines, the ability of Rhinopithecus to adapt their activity budget at high elevations may make them less vulnerable to climate change, while the greater sensitivity of Trachypithecus to heat may make them more vulnerable to climate change.
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Robbins MM, Ortmann S, Seiler N. Dietary variability of western gorillas (Gorilla gorilla gorilla). PLoS One 2022; 17:e0271576. [PMID: 36001558 PMCID: PMC9401121 DOI: 10.1371/journal.pone.0271576] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 07/04/2022] [Indexed: 11/19/2022] Open
Abstract
Spatial and temporal variability in the availability of food resources will lead to variation in a species’ diet, which can then influence patterns of space use, sociality, and life history characteristics. Despite such potential impacts, little information is available about dietary variability for some species with large geographical ranges. Here we quantify the diet and nutritional content of plants consumed by western lowland gorillas (Gorilla gorilla gorilla) in Loango National Park, Gabon over a 2.6 year period and make comparisons with two study sites located 800 km away. The major foods consumed by the Loango gorillas differed greatly from the other two study sites, but gorillas at all three locations spent a similar proportion of feeding time consuming herbaceous vegetation and tree leaves (~ 50%) and fruit (35%). The Loango gorillas spent approximately 10% of feeding time eating nuts, which were not consumed at the other two study sites. Gorillas at those sites spent about 5% of feeding time eating insects, which were not consumed by Loango gorillas. Even though the species composition of the diet differed among the three sites, the nutritional composition of the major food items differed very little, suggesting that western gorillas consume foods of similar nutritional values to meet their dietary needs. This study shows the flexibility of diet of a species with a wide geographic distribution, which has implications for understanding variation in life history characteristics and can be useful for conservation management plans.
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Affiliation(s)
- Martha M. Robbins
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- * E-mail:
| | - Sylvia Ortmann
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Nicole Seiler
- Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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6
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Fiorenza L, Harty T, Janocha MM, Kullmer O, Nguyen HN, Bortolini E, Benazzi S. Understanding dietary ecology in great apes from dental macrowear analysis. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022. [PMCID: PMC9544277 DOI: 10.1002/ajpa.24533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Objectives Dietary diversity in primates is reflected in their dental morphology, with differences in size and shape of teeth. The objective of this study is to investigate the relationship between molar morphology and macrowear patterns in Pongo, Gorilla, and Pan to obtain dietary information. Methods We have examined 68 second lower molars using the Occlusal Fingerprint Analysis method including 18 chimpanzees, 28 gorillas, and 22 orangutans. We selected only molars from wildshot specimens characterized by a moderate degree of wear. High‐resolution digital models of teeth were created using a white scanning light system with a resolution of 45 μm. Results The macrowear patterns of Pan were significantly different from those of Gorilla and of Pongo, differences that are mostly due to shearing wear. Gorilla and Pongo macrowear patterns are dominated by phase II areas, followed by lingual phase I facets, while in Pan we observe a significant increase in buccal phase I facets. The latter group also displays the highest macrowear variation across the sample examined in this study. Conclusions The molar macrowear patterns of the great apes analyzed in this study did not confirm our initial hypothesis of finding larger crushing and grinding areas in Pongo and more shearing wear in Gorilla. Pan shows the most variable macrowear, which is probably associated with their more flexible diet. The similarity between Pongo and Gorilla macrowear patterns may be due to a larger intake of mechanically challenging foods that could obfuscate dietary wear signals generated by softer foods.
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Affiliation(s)
- Luca Fiorenza
- Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology Monash University Melbourne Victoria Australia
| | - Teagan Harty
- Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology Monash University Melbourne Victoria Australia
| | - Marcel M. Janocha
- Division of Palaeoanthropology Senckenberg Research Institute and Natural History Museum Frankfurt Frankfurt am Main Germany
- Department of Palaeobiology and Environment, Institute of Ecology Evolution, and Diversity, Goethe University Frankfurt Germany
| | - Ottmar Kullmer
- Division of Palaeoanthropology Senckenberg Research Institute and Natural History Museum Frankfurt Frankfurt am Main Germany
- Department of Palaeobiology and Environment, Institute of Ecology Evolution, and Diversity, Goethe University Frankfurt Germany
| | - Huynh N. Nguyen
- School of Mechanical Engineering Hanoi University of Science and Technology Hanoi Vietnam
| | - Eugenio Bortolini
- Department of Archaeology and Anthropology, Institución Milá y Fontanals de investigación en Humanidades Consejo Superior de Investigaciones Científicas (IMF – CSIC) Barcelona Spain
- Culture and Socio‐Ecological Dynamics, Department of Humanities Universitat Pompeu Fabra Barcelona Spain
| | - Stefano Benazzi
- Department of Cultural Heritage University of Bologna Ravenna Italy
- Department of Human Evolution Max Planck Institute for Evolutionary Anthropology Leipzig Germany
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7
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Harty T, Berthaume MA, Bortolini E, Evans AR, Galbany J, Guy F, Kullmer O, Lazzari V, Romero A, Fiorenza L. Dental macrowear reveals ecological diversity of Gorilla spp. Sci Rep 2022; 12:9203. [PMID: 35655071 PMCID: PMC9163330 DOI: 10.1038/s41598-022-12488-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/10/2022] [Indexed: 11/11/2022] Open
Abstract
Size and shape variation of molar crowns in primates plays an important role in understanding how species adapted to their environment. Gorillas are commonly considered to be folivorous primates because they possess sharp cusped molars which are adapted to process fibrous leafy foods. However, the proportion of fruit in their diet can vary significantly depending on their habitats. While tooth morphology can tell us what a tooth is capable of processing, tooth wear can help us to understand how teeth have been used during mastication. The objective of this study is to explore if differences in diet at the subspecies level can be detected by the analysis of molar macrowear. We analysed a large sample of second lower molars of Grauer’s, mountain and western lowland gorilla by combining the Occlusal Fingerprint Analysis method with other dental measurements. We found that Grauer’s and western lowland gorillas are characterised by a macrowear pattern indicating a larger intake of fruit in their diet, while mountain gorilla’s macrowear is associated with the consumption of more folivorous foods. We also found that the consumption of herbaceous foods is generally associated with an increase in dentine and enamel wear, confirming the results of previous studies.
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Affiliation(s)
- Teagan Harty
- Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia
| | - Michael A Berthaume
- Division Mechanical Engineering and Design, London South Bank University, London, UK
| | - Eugenio Bortolini
- Department of Archaeology and Anthropology, Institución Milá y Fontanals de Investigación en Humanidades, Barcelona, Spain.,Culture and Socio-Ecological Dynamics, Department of Humanities, Universitat Pompeu Fabra Ramon Trias Fargas, Barcelona, Spain
| | - Alistair R Evans
- School of Biological Sciences, Monash University, Melbourne, VIC, Australia.,Geosciences, Museums Victoria, Melbourne, VIC, Australia
| | - Jordi Galbany
- Department of Anthropology, Center for the Advanced Study of Human Paleobiology, The George Washington University, Washington, DC, USA.,Department of Clinical Psychology and Psychobiology, University of Barcelona, Barcelona, Spain
| | - Franck Guy
- Laboratory PALEVOPRIM, UMR CNRS 7262, University of Poitiers, Poitiers, France
| | - Ottmar Kullmer
- Department of Paleoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt, Germany.,Department of Paleobiology and Environment, Institute of Ecology, Evolution, and Diversity, Goethe University, Frankfurt, Germany
| | - Vincent Lazzari
- Laboratory PALEVOPRIM, UMR CNRS 7262, University of Poitiers, Poitiers, France
| | - Alejandro Romero
- Departamento de Biotecnología, Universidad de Alicante, 03690, Alicante, Spain.,Instituto Universitario de Investigación en Arqueología y Patrimonio Histórico (INAPH), Universidad de Alicante, 03690, Alicante, Spain
| | - Luca Fiorenza
- Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, Australia.
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McGrath K, Eriksen AB, García-Martínez D, Galbany J, Gómez-Robles A, Massey JS, Fatica LM, Glowacka H, Arbenz-Smith K, Muvunyi R, Stoinski TS, Cranfield MR, Gilardi K, Shalukoma C, de Merode E, Gilissen E, Tocheri MW, McFarlin SC, Heuzé Y. Facial asymmetry tracks genetic diversity among Gorilla subspecies. Proc Biol Sci 2022; 289:20212564. [PMID: 35193404 PMCID: PMC8864355 DOI: 10.1098/rspb.2021.2564] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Mountain gorillas are particularly inbred compared to other gorillas and even the most inbred human populations. As mountain gorilla skeletal material accumulated during the 1970s, researchers noted their pronounced facial asymmetry and hypothesized that it reflects a population-wide chewing side preference. However, asymmetry has also been linked to environmental and genetic stress in experimental models. Here, we examine facial asymmetry in 114 crania from three Gorilla subspecies using 3D geometric morphometrics. We measure fluctuating asymmetry (FA), defined as random deviations from perfect symmetry, and population-specific patterns of directional asymmetry (DA). Mountain gorillas, with a current population size of about 1000 individuals, have the highest degree of facial FA (explaining 17% of total facial shape variation), followed by Grauer gorillas (9%) and western lowland gorillas (6%), despite the latter experiencing the greatest ecological and dietary variability. DA, while significant in all three taxa, explains relatively less shape variation than FA does. Facial asymmetry correlates neither with tooth wear asymmetry nor increases with age in a mountain gorilla subsample, undermining the hypothesis that facial asymmetry is driven by chewing side preference. An examination of temporal trends shows that stress-induced developmental instability has increased over the last 100 years in these endangered apes.
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Affiliation(s)
- Kate McGrath
- State University of New York, College at Oneonta, Oneonta, NY 13820, USA,Univ. Bordeaux, CNRS, MC, PACEA, UMR 5199, 33615, Pessac, France,Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington, DC 20052, USA,Department of Anthropology, The Ohio State University, Columbus, OH, USA
| | | | - Daniel García-Martínez
- Physical Anthropology Unit, Department of Biodiversity, Ecology, and Evolution, Faculty of Biological Sciences, Complutense University of Madrid, Madrid, Spain
| | - Jordi Galbany
- Univ. Bordeaux, CNRS, MC, PACEA, UMR 5199, 33615, Pessac, France,Department of Clinical Psychology and Psychobiology, University of Barcelona, Passeig de la Vall d'Hebron 171, 08035 Barcelona, Spain
| | - Aida Gómez-Robles
- Department of Anthropology, University College London, 14 Taviton St, London WC1H 0BW, UK
| | - Jason S. Massey
- Department of Anatomy and Developmental Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Lawrence M. Fatica
- Univ. Bordeaux, CNRS, MC, PACEA, UMR 5199, 33615, Pessac, France,Department of Physiological Sciences, University of Florida College of Veterinary Medicine, Gainesville, FL, USA
| | - Halszka Glowacka
- Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix 85004, USA
| | - Keely Arbenz-Smith
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA
| | - Richard Muvunyi
- Department of Tourism and Conservation, Rwanda Development Board, Kigali, Rwanda
| | - Tara S. Stoinski
- The Dian Fossey Gorilla Fund International, Atlanta, GA 30315, USA
| | - Michael R. Cranfield
- Gorilla Doctors (MGVP, Inc.), Karen C. Drayer Wildlife Health Center, University of California Davis, Davis, CA 95616, USA
| | - Kirsten Gilardi
- Gorilla Doctors (MGVP, Inc.), Karen C. Drayer Wildlife Health Center, University of California Davis, Davis, CA 95616, USA
| | - Chantal Shalukoma
- Institut Congolais pour la Conservation de la Nature, Virunga National Park, Rumangabo, Democratic Republic of Congo
| | - Emmanuel de Merode
- Institut Congolais pour la Conservation de la Nature, Virunga National Park, Rumangabo, Democratic Republic of Congo
| | - Emmanuel Gilissen
- Department of African Zoology, Royal Museum for Central Africa, Tervuren, Belgium,Laboratory of Histology and Neuropathology, Université Libre de Bruxelles, Brussels, Belgium
| | - Matthew W. Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, Ontario, Canada P7B 5E1,Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA,Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Shannon C. McFarlin
- Univ. Bordeaux, CNRS, MC, PACEA, UMR 5199, 33615, Pessac, France,Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA
| | - Yann Heuzé
- State University of New York, College at Oneonta, Oneonta, NY 13820, USA
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9
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Robbins MM, Robbins AM. Variability of weaning age in mountain gorillas (Gorilla beringei beringei). AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 174:776-784. [PMID: 33511629 DOI: 10.1002/ajpa.24237] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/17/2020] [Accepted: 01/08/2021] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Weaning is a key life history milestone for mammals that represents both the end of nutritional investment from the perspective of mothers and the start of complete nutritional independence for the infants. The age at weaning may vary depending on ecological, social, and demographic factors experienced by the mother and infant. Bwindi mountain gorillas live in different environmental conditions and have longer interbirth intervals than their counterparts in the Virunga Volcanoes, yet other life history characteristics of this population remain less well known. We use long-term data from Bwindi Impenetrable National Park, Uganda to examine factors related to weaning age. MATERIALS AND METHODS We analyzed data on infants born in four mountain gorilla groups in Bwindi to quantify their age of weaning (defined as last nipple contact) and to test if the sex of offspring, parity, and dominance rank of mother influences age of weaning. We also compared the age at weaning and time to conception after resumption of mating in Bwindi and Virunga gorillas. RESULTS Bwindi gorillas were weaned at an average age of 57.5 months. No difference was found between age of weaning for primiparous and multiparous mothers, nor did maternal dominance rank influence age of weaning, but sons were weaned at a later age than daughters. The majority of Bwindi mothers were still suckling when they resumed mating and mothers generally conceived before they weaned their previous offspring. The age of weaning was significantly later in Bwindi than in Virunga gorillas. After mothers resumed mating, the time to conceiving the next offspring was not significantly longer for Bwindi females than Virungas females (6 vs. 4 months). DISCUSSION Later weaning age for sons than daughters is similar to findings of other studies of great apes. Bwindi mountain gorillas are weaned at approximately the same age as western gorillas and chimpanzees, which is more than a year later than Virunga mountain gorillas. The results of this study suggest that variation in ecological conditions of populations living in close geographic proximity can result in variation in life history patterns, which has implications for understanding the evolution of the unique life history patterns of humans.
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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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10
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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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