1
|
Kralick AE, Zemel BS, Nolan C, Lin P, Tocheri MW. Relative leg-to-arm skeletal strength proportions in orangutans by species and sex. J Hum Evol 2024; 188:103496. [PMID: 38412694 DOI: 10.1016/j.jhevol.2024.103496] [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: 04/25/2023] [Revised: 01/02/2024] [Accepted: 01/05/2024] [Indexed: 02/29/2024]
Abstract
Among extant great apes, orangutans climb most frequently. However, Bornean orangutans (Pongo pygmaeus) exhibit higher frequencies of terrestrial locomotion than do Sumatran orangutans (Pongo abelii). Variation in long bone cross-sectional geometry is known to reflect differential loading of the limbs. Thus, Bornean orangutans should show greater relative leg-to-arm strength than their Sumatran counterparts. Using skeletal specimens from museum collections, we measured two cross-sectional geometric measures of bone strength: the polar section modulus (Zpol) and the ratio of maximum to minimum area moments of inertia (Imax/Imin), at the midshaft of long bones in Bornean (n = 19) and Sumatran adult orangutans (n = 12) using medical CT and peripheral quantitative CT scans, and compared results to published data of other great apes. Relative leg-to-arm strength was quantified using ratios of femur and tibia over humerus, radius, and ulna, respectively. Differences between orangutan species and between sexes in median ratios were assessed using Wilcoxon rank sum tests. The tibia of Bornean orangutans was stronger relative to the humerus and the ulna than in Sumatran orangutans (p = 0.008 and 0.025, respectively), consistent with behavioral studies that indicate higher frequencies of terrestrial locomotion in the former. In three Zpol ratios, adult female orangutans showed greater leg-to-arm bone strength compared to flanged males, which may relate to females using their legs more during arboreal locomotion than in adult flanged males. A greater amount of habitat discontinuity on Borneo compared to Sumatra has been posited as a possible explanation for observed interspecific differences in locomotor behaviors, but recent camera trap studies has called this into question. Alternatively, greater frequencies of terrestriality in Pongo pygmaeus may be due to the absence of tigers on Borneo. The results of this study are consistent with the latter explanation given that habitat continuity was greater a century ago when our study sample was collected.
Collapse
Affiliation(s)
- Alexandra E Kralick
- Studies of Women, Gender, and Sexuality, Harvard University, Cambridge, 02138, USA; Department of Anthropology, University of Pennsylvania, Philadelphia, Pennsylvania, 19104, USA.
| | - Babette S Zemel
- Division of Gastroenterology, Hepatology and Nutrition, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Pediatrics, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Clara Nolan
- Fine Arts Department, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Computer and Information Science, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Phillip Lin
- Stockdale High School, Bakersfield, CA, 93311, USA
| | - Matthew W Tocheri
- Department of Anthropology, Lakehead University, Thunder Bay, Ontario, P7B 5E1, Canada; Human Origins Program, National Museum of Natural History, Smithsonian Institution, Washington, D.C., 20013, USA; Australian Research Council Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, New South Wales, NSW, 2522, Australia
| |
Collapse
|
2
|
Sharpe SL, Anderson AP, Cooper I, James TY, Kralick AE, Lindahl H, Lipshutz SE, McLaughlin JF, Subramaniam B, Weigel AR, Lewis AK. Sex and Biology: Broader Impacts Beyond the Binary. Integr Comp Biol 2023; 63:960-967. [PMID: 37591671 PMCID: PMC10563654 DOI: 10.1093/icb/icad113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 06/04/2023] [Accepted: 06/10/2023] [Indexed: 08/19/2023] Open
Abstract
What are the implications of misunderstanding sex as a binary, and why is it essential for scientists to incorporate a more expansive view of biological sex in our teaching and research? This roundtable will include many of our symposium speakers, including biologists and intersex advocates, to discuss these topics and visibilize the link between ongoing reification of dyadic sex within scientific communities and the social, political, and medical oppression faced by queer, transgender, and especially intersex communities. As with the symposium as a whole, this conversation is designed to bring together empirical research and implementation of equity, inclusion, and justice principles, which are often siloed into separate rooms and conversations at academic conferences. Given the local and national attacks on the rights of intersex individuals and access to medical care and bodily autonomy, this interdisciplinary discussion is both timely and urgent.
Collapse
Affiliation(s)
- Sam L Sharpe
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
| | | | - Idelle Cooper
- Department of Biology, James Madison University, Harrisonburg, VA 22807, USA
| | - Timothy Y James
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alexandra E Kralick
- Department of Anthropology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Sara E Lipshutz
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - J F McLaughlin
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA 94720, USA
| | - Banu Subramaniam
- Department of Women, Gender, Sexuality Studies, University of Massachusetts-Amherst, Amherst, MA 01003, USA
| | | | - A Kelsey Lewis
- Department of Global Gender and Sexuality Studies, University at Buffalo-SUNY, Buffalo, New York 14260, USA
| |
Collapse
|
3
|
Taylor LU, Prum RO. SOCIAL CONTEXT AND THE EVOLUTION OF DELAYED REPRODUCTION IN BIRDS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551693. [PMID: 37577720 PMCID: PMC10418290 DOI: 10.1101/2023.08.02.551693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Classic life history theory makes generalized predictions about phenotypic correlations across large clades. Modern comparative tests of these correlations account for the underlying structure of phylogenetic trees. Yet neither life history theory nor phylogenetic comparative methods automatically specify how biological mechanisms generate correlations. This problem is evident in comparative analyses of birds. Birds show a correlation between body size and age at first reproduction, but do not actually grow larger if they delay reproduction. Instead, field studies raise the hypothesis that social contexts-especially cooperative breeding, coloniality, and lekking-generate unique demands for behavioral development, which in turn result in delayed reproduction. Here, we support that hypothesis with a comparative dataset spanning 961 species in 155 avian families. Continuous (Ornstein-Uhlenbeck), discrete (hidden state Markov), and phylogenetic regression models revealed delayed reproduction in colonial birds, a weaker signal in cooperative birds, and the consistent evolution of sexual bimaturism in polygynous, lekking birds. These results show an association between diverse social contexts, sex-specific developmental demands, and life history evolution in birds. Considering this diversity, we discuss how even statistically powerful phylogenetic correlations-whether focused on mass, lifespan, or broad social categories-can ultimately fail to model the history of life history evolution.
Collapse
Affiliation(s)
- Liam U. Taylor
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA
| | - Richard O. Prum
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT 06511, USA
| |
Collapse
|