Determining sex of adult Pacific walruses from mandible measurements
Abstract 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,...
Published in: | Journal of Mammalogy |
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2020
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Online Access: | http://dx.doi.org/10.1093/jmammal/gyaa051 http://academic.oup.com/jmammal/article-pdf/101/4/941/33727478/gyaa051.pdf |
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croxfordunivpr:10.1093/jmammal/gyaa051 2023-05-15T15:09:07+02:00 Determining sex of adult Pacific walruses from mandible measurements Taylor, Nathan Clark, Casey T Misarti, Nicole Horstmann, Lara Hohn, Aleta National Science Foundation Bureau of Ocean Energy Management 2020 http://dx.doi.org/10.1093/jmammal/gyaa051 http://academic.oup.com/jmammal/article-pdf/101/4/941/33727478/gyaa051.pdf en eng Oxford University Press (OUP) http://creativecommons.org/licenses/by-nc/4.0/ CC-BY-NC Journal of Mammalogy volume 101, issue 4, page 941-950 ISSN 0022-2372 1545-1542 Nature and Landscape Conservation Genetics Animal Science and Zoology Ecology Ecology, Evolution, Behavior and Systematics journal-article 2020 croxfordunivpr https://doi.org/10.1093/jmammal/gyaa051 2022-09-23T11:04:20Z Abstract 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. Article in Journal/Newspaper Arctic Odobenus rosmarus Alaska walrus* Oxford University Press (via Crossref) Arctic Pacific Journal of Mammalogy 101 4 941 950 |
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Open Polar |
collection |
Oxford University Press (via Crossref) |
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croxfordunivpr |
language |
English |
topic |
Nature and Landscape Conservation Genetics Animal Science and Zoology Ecology Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Nature and Landscape Conservation Genetics Animal Science and Zoology Ecology Ecology, Evolution, Behavior and Systematics Taylor, Nathan Clark, Casey T Misarti, Nicole Horstmann, Lara Determining sex of adult Pacific walruses from mandible measurements |
topic_facet |
Nature and Landscape Conservation Genetics Animal Science and Zoology Ecology Ecology, Evolution, Behavior and Systematics |
description |
Abstract 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. |
author2 |
Hohn, Aleta National Science Foundation Bureau of Ocean Energy Management |
format |
Article in Journal/Newspaper |
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 (OUP) |
publishDate |
2020 |
url |
http://dx.doi.org/10.1093/jmammal/gyaa051 http://academic.oup.com/jmammal/article-pdf/101/4/941/33727478/gyaa051.pdf |
geographic |
Arctic Pacific |
geographic_facet |
Arctic Pacific |
genre |
Arctic Odobenus rosmarus Alaska walrus* |
genre_facet |
Arctic Odobenus rosmarus Alaska walrus* |
op_source |
Journal of Mammalogy volume 101, issue 4, page 941-950 ISSN 0022-2372 1545-1542 |
op_rights |
http://creativecommons.org/licenses/by-nc/4.0/ |
op_rightsnorm |
CC-BY-NC |
op_doi |
https://doi.org/10.1093/jmammal/gyaa051 |
container_title |
Journal of Mammalogy |
container_volume |
101 |
container_issue |
4 |
container_start_page |
941 |
op_container_end_page |
950 |
_version_ |
1766340352701104128 |