Tusk anomalies in narwhals (Monodon monoceros) from Greenland
The elongated, spiraled tusk of male narwhals (Monodon monoceros) grows continuously throughout the life of the whale and is most likely a secondary sexual trait used in male–male hierarchical competition and possibly in female mate choice. Sex determination in narwhals is typically based on the pre...
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Norwegian Polar Institute
2022
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ftdoajarticles:oai:doaj.org/article:de880de937034699b7f365ad7fa29695 2023-05-15T15:10:41+02:00 Tusk anomalies in narwhals (Monodon monoceros) from Greenland Eva Garde Mads Peter Heide-Jørgensen 2022-06-01T00:00:00Z https://doi.org/10.33265/polar.v41.8343 https://doaj.org/article/de880de937034699b7f365ad7fa29695 EN eng Norwegian Polar Institute https://polarresearch.net/index.php/polar/article/view/8343/14642 https://doaj.org/toc/0800-0395 https://doaj.org/toc/1751-8369 0800-0395 1751-8369 doi:10.33265/polar.v41.8343 https://doaj.org/article/de880de937034699b7f365ad7fa29695 Polar Research, Vol 41, Pp 1-8 (2022) arctic cetacean marine mammal teeth dentition inuit narwhal hunt Environmental sciences GE1-350 Oceanography GC1-1581 article 2022 ftdoajarticles https://doi.org/10.33265/polar.v41.8343 2022-12-30T21:49:43Z The elongated, spiraled tusk of male narwhals (Monodon monoceros) grows continuously throughout the life of the whale and is most likely a secondary sexual trait used in male–male hierarchical competition and possibly in female mate choice. Sex determination in narwhals is typically based on the presence (male) or absence (female) of an erupted tusk, but anomalies such as females with tusks, tuskless males or double-tusked whales occur, although infrequently. In this study, we collected reproductive data and recorded the presence or absence of a tusk in narwhals from the Inuit hunt in Greenland (1993 and 2010–19) with the purpose of estimating the frequency of tusk anomalies. We found that of the 173 whales, 2.9% displayed tusk anomalies. Tusked females constituted 1.5% of sampled females, tuskless males 2.8% of sampled males and double-tusked males 0.9% of sampled males. Biological information on a tusked female, a tuskless male and a double-tusked male was collected and is presented here. The tusked female was sexually mature, and 18 ovarian scars (indicating pregnancies) documented a long reproductive lifespan. The complete female tusk was estimated to be between 146 and 151 cm in length. The tuskless male was sexually maturing, as indicated by body dimensions, and the double-tusked male was sexually immature, with the two tusks measuring <90 cm in length. Although narwhals exhibit extremely low levels of genetic diversity, tusk anomalies persist in the populations, perhaps facilitated by the reproductive ability of whales with tusk anomalies. Article in Journal/Newspaper Arctic Greenland inuit Monodon monoceros narwhal* Polar Research Directory of Open Access Journals: DOAJ Articles Arctic Greenland Polar Research 41 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
arctic cetacean marine mammal teeth dentition inuit narwhal hunt Environmental sciences GE1-350 Oceanography GC1-1581 |
spellingShingle |
arctic cetacean marine mammal teeth dentition inuit narwhal hunt Environmental sciences GE1-350 Oceanography GC1-1581 Eva Garde Mads Peter Heide-Jørgensen Tusk anomalies in narwhals (Monodon monoceros) from Greenland |
topic_facet |
arctic cetacean marine mammal teeth dentition inuit narwhal hunt Environmental sciences GE1-350 Oceanography GC1-1581 |
description |
The elongated, spiraled tusk of male narwhals (Monodon monoceros) grows continuously throughout the life of the whale and is most likely a secondary sexual trait used in male–male hierarchical competition and possibly in female mate choice. Sex determination in narwhals is typically based on the presence (male) or absence (female) of an erupted tusk, but anomalies such as females with tusks, tuskless males or double-tusked whales occur, although infrequently. In this study, we collected reproductive data and recorded the presence or absence of a tusk in narwhals from the Inuit hunt in Greenland (1993 and 2010–19) with the purpose of estimating the frequency of tusk anomalies. We found that of the 173 whales, 2.9% displayed tusk anomalies. Tusked females constituted 1.5% of sampled females, tuskless males 2.8% of sampled males and double-tusked males 0.9% of sampled males. Biological information on a tusked female, a tuskless male and a double-tusked male was collected and is presented here. The tusked female was sexually mature, and 18 ovarian scars (indicating pregnancies) documented a long reproductive lifespan. The complete female tusk was estimated to be between 146 and 151 cm in length. The tuskless male was sexually maturing, as indicated by body dimensions, and the double-tusked male was sexually immature, with the two tusks measuring <90 cm in length. Although narwhals exhibit extremely low levels of genetic diversity, tusk anomalies persist in the populations, perhaps facilitated by the reproductive ability of whales with tusk anomalies. |
format |
Article in Journal/Newspaper |
author |
Eva Garde Mads Peter Heide-Jørgensen |
author_facet |
Eva Garde Mads Peter Heide-Jørgensen |
author_sort |
Eva Garde |
title |
Tusk anomalies in narwhals (Monodon monoceros) from Greenland |
title_short |
Tusk anomalies in narwhals (Monodon monoceros) from Greenland |
title_full |
Tusk anomalies in narwhals (Monodon monoceros) from Greenland |
title_fullStr |
Tusk anomalies in narwhals (Monodon monoceros) from Greenland |
title_full_unstemmed |
Tusk anomalies in narwhals (Monodon monoceros) from Greenland |
title_sort |
tusk anomalies in narwhals (monodon monoceros) from greenland |
publisher |
Norwegian Polar Institute |
publishDate |
2022 |
url |
https://doi.org/10.33265/polar.v41.8343 https://doaj.org/article/de880de937034699b7f365ad7fa29695 |
geographic |
Arctic Greenland |
geographic_facet |
Arctic Greenland |
genre |
Arctic Greenland inuit Monodon monoceros narwhal* Polar Research |
genre_facet |
Arctic Greenland inuit Monodon monoceros narwhal* Polar Research |
op_source |
Polar Research, Vol 41, Pp 1-8 (2022) |
op_relation |
https://polarresearch.net/index.php/polar/article/view/8343/14642 https://doaj.org/toc/0800-0395 https://doaj.org/toc/1751-8369 0800-0395 1751-8369 doi:10.33265/polar.v41.8343 https://doaj.org/article/de880de937034699b7f365ad7fa29695 |
op_doi |
https://doi.org/10.33265/polar.v41.8343 |
container_title |
Polar Research |
container_volume |
41 |
_version_ |
1766341661744431104 |