Determining sex of adult Pacific walruses from mandible measurements
Pacific walruses (Odobenus rosmarus divergens) play a vital role in Arctic marine ecosystems and the subsistence lifestyle of Alaska Native communities. Museum collections contain numerous archaeological and historic walrus specimens that have proven useful in a variety of studies; however, for many...
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ftpubmed:oai:pubmedcentral.nih.gov:7528639 2023-05-15T15:07:48+02:00 Determining sex of adult Pacific walruses from mandible measurements Taylor, Nathan Clark, Casey T Misarti, Nicole Horstmann, Lara 2020-06-20 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528639/ https://doi.org/10.1093/jmammal/gyaa051 en eng Oxford University Press http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528639/ http://dx.doi.org/10.1093/jmammal/gyaa051 © The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Mammalogists. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com CC-BY-NC J Mammal Feature Articles Text 2020 ftpubmed https://doi.org/10.1093/jmammal/gyaa051 2020-10-11T00:25:44Z Pacific walruses (Odobenus rosmarus divergens) play a vital role in Arctic marine ecosystems and the subsistence lifestyle of Alaska Native communities. Museum collections contain numerous archaeological and historic walrus specimens that have proven useful in a variety of studies; however, for many cases, the sex of these specimens is unknown. Sexes of adult (> 5 years determined by tooth aging) Atlantic walruses (Odobenus rosmarus rosmarus) have been accurately determined in previous studies using mandible measurements. We tested the validity of this approach for Pacific walruses, and used full fusion of the mandibular symphysis to define adults. Using high precision digital calipers (± 0.01 mm), four measurements were taken either on the left or right side of 91 walrus mandibles: 80 modern mandibles (70 known-sex specimens; 10 unknown-sex specimens) and 11 archaeological mandibles of unknown sex. We used linear discriminant function analysis (LDFA) to determine what measurements best distinguished Pacific walrus males from females. Minimum mandible thickness had the most predictive power, whereas mandible length, height, and depth, were less predictive. Posterior probabilities indicated that LDFA classified the known-sex Pacific walruses with 100% accuracy, and unknown sex with ≥ 90% probability. The ability to define the sex of unknown individuals accurately could greatly increase the sample size of future projects dealing with skeletal remains, and will improve future research efforts. Text Arctic Odobenus rosmarus Alaska walrus* PubMed Central (PMC) Arctic Pacific Journal of Mammalogy 101 4 941 950 |
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Feature Articles |
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Feature Articles Taylor, Nathan Clark, Casey T Misarti, Nicole Horstmann, Lara Determining sex of adult Pacific walruses from mandible measurements |
topic_facet |
Feature Articles |
description |
Pacific walruses (Odobenus rosmarus divergens) play a vital role in Arctic marine ecosystems and the subsistence lifestyle of Alaska Native communities. Museum collections contain numerous archaeological and historic walrus specimens that have proven useful in a variety of studies; however, for many cases, the sex of these specimens is unknown. Sexes of adult (> 5 years determined by tooth aging) Atlantic walruses (Odobenus rosmarus rosmarus) have been accurately determined in previous studies using mandible measurements. We tested the validity of this approach for Pacific walruses, and used full fusion of the mandibular symphysis to define adults. Using high precision digital calipers (± 0.01 mm), four measurements were taken either on the left or right side of 91 walrus mandibles: 80 modern mandibles (70 known-sex specimens; 10 unknown-sex specimens) and 11 archaeological mandibles of unknown sex. We used linear discriminant function analysis (LDFA) to determine what measurements best distinguished Pacific walrus males from females. Minimum mandible thickness had the most predictive power, whereas mandible length, height, and depth, were less predictive. Posterior probabilities indicated that LDFA classified the known-sex Pacific walruses with 100% accuracy, and unknown sex with ≥ 90% probability. The ability to define the sex of unknown individuals accurately could greatly increase the sample size of future projects dealing with skeletal remains, and will improve future research efforts. |
format |
Text |
author |
Taylor, Nathan Clark, Casey T Misarti, Nicole Horstmann, Lara |
author_facet |
Taylor, Nathan Clark, Casey T Misarti, Nicole Horstmann, Lara |
author_sort |
Taylor, Nathan |
title |
Determining sex of adult Pacific walruses from mandible measurements |
title_short |
Determining sex of adult Pacific walruses from mandible measurements |
title_full |
Determining sex of adult Pacific walruses from mandible measurements |
title_fullStr |
Determining sex of adult Pacific walruses from mandible measurements |
title_full_unstemmed |
Determining sex of adult Pacific walruses from mandible measurements |
title_sort |
determining sex of adult pacific walruses from mandible measurements |
publisher |
Oxford University Press |
publishDate |
2020 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528639/ https://doi.org/10.1093/jmammal/gyaa051 |
geographic |
Arctic Pacific |
geographic_facet |
Arctic Pacific |
genre |
Arctic Odobenus rosmarus Alaska walrus* |
genre_facet |
Arctic Odobenus rosmarus Alaska walrus* |
op_source |
J Mammal |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528639/ http://dx.doi.org/10.1093/jmammal/gyaa051 |
op_rights |
© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Mammalogists. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com |
op_rightsnorm |
CC-BY-NC |
op_doi |
https://doi.org/10.1093/jmammal/gyaa051 |
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Journal of Mammalogy |
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101 |
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4 |
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941 |
op_container_end_page |
950 |
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1766339228841541632 |