Sperm whale social units: variation and change
Sperm whale (Physeter macrocephalus) photoidentification data spanning 12 years of study around the Galápagos Islands were examined to investigate the size, variability, and stability of social units. Adult females and immature whales of both sexes have two types of associates: "constant compan...
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1998
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Online Access: | http://dx.doi.org/10.1139/z98-087 http://www.nrcresearchpress.com/doi/pdf/10.1139/z98-087 |
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crcansciencepubl:10.1139/z98-087 2024-04-07T07:55:28+00:00 Sperm whale social units: variation and change Christal, Jenny Whitehead, Hal Lettevall, Erland 1998 http://dx.doi.org/10.1139/z98-087 http://www.nrcresearchpress.com/doi/pdf/10.1139/z98-087 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 76, issue 8, page 1431-1440 ISSN 0008-4301 1480-3283 Animal Science and Zoology Ecology, Evolution, Behavior and Systematics journal-article 1998 crcansciencepubl https://doi.org/10.1139/z98-087 2024-03-08T00:37:50Z Sperm whale (Physeter macrocephalus) photoidentification data spanning 12 years of study around the Galápagos Islands were examined to investigate the size, variability, and stability of social units. Adult females and immature whales of both sexes have two types of associates: "constant companions," which are members of an individual's "stable" social unit, and "casual acquaintances," which are temporarily associating members of different units. We analysed long-term association patterns and calculated that individuals have a mean of 11.3 constant companions. Estimated social unit size ranged from 3 to 24 individuals. Evidence of splitting and merging of units and of transfer of individuals between units is presented. The estimated overall frequency of these unit-membership changes is 6.3% per individual per year. These forms of unit dynamics are rare in species with male dispersal and matrilineally related social groups, and cannot be easily explained in this species. There is considerable variation in unit size (perhaps caused by demographic processes), suggesting that the benefits of remaining in a social unit usually outweigh selection for some optimal unit size. However, the occurrence of merging and transfers suggests that the ecological or social cost/benefit of leaving one's matrilineal unit may sometimes outweigh the cost/benefit of staying. Article in Journal/Newspaper Physeter macrocephalus Sperm whale Canadian Science Publishing Canadian Journal of Zoology 76 8 1431 1440 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
topic |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics Christal, Jenny Whitehead, Hal Lettevall, Erland Sperm whale social units: variation and change |
topic_facet |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
description |
Sperm whale (Physeter macrocephalus) photoidentification data spanning 12 years of study around the Galápagos Islands were examined to investigate the size, variability, and stability of social units. Adult females and immature whales of both sexes have two types of associates: "constant companions," which are members of an individual's "stable" social unit, and "casual acquaintances," which are temporarily associating members of different units. We analysed long-term association patterns and calculated that individuals have a mean of 11.3 constant companions. Estimated social unit size ranged from 3 to 24 individuals. Evidence of splitting and merging of units and of transfer of individuals between units is presented. The estimated overall frequency of these unit-membership changes is 6.3% per individual per year. These forms of unit dynamics are rare in species with male dispersal and matrilineally related social groups, and cannot be easily explained in this species. There is considerable variation in unit size (perhaps caused by demographic processes), suggesting that the benefits of remaining in a social unit usually outweigh selection for some optimal unit size. However, the occurrence of merging and transfers suggests that the ecological or social cost/benefit of leaving one's matrilineal unit may sometimes outweigh the cost/benefit of staying. |
format |
Article in Journal/Newspaper |
author |
Christal, Jenny Whitehead, Hal Lettevall, Erland |
author_facet |
Christal, Jenny Whitehead, Hal Lettevall, Erland |
author_sort |
Christal, Jenny |
title |
Sperm whale social units: variation and change |
title_short |
Sperm whale social units: variation and change |
title_full |
Sperm whale social units: variation and change |
title_fullStr |
Sperm whale social units: variation and change |
title_full_unstemmed |
Sperm whale social units: variation and change |
title_sort |
sperm whale social units: variation and change |
publisher |
Canadian Science Publishing |
publishDate |
1998 |
url |
http://dx.doi.org/10.1139/z98-087 http://www.nrcresearchpress.com/doi/pdf/10.1139/z98-087 |
genre |
Physeter macrocephalus Sperm whale |
genre_facet |
Physeter macrocephalus Sperm whale |
op_source |
Canadian Journal of Zoology volume 76, issue 8, page 1431-1440 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z98-087 |
container_title |
Canadian Journal of Zoology |
container_volume |
76 |
container_issue |
8 |
container_start_page |
1431 |
op_container_end_page |
1440 |
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1795672653587021824 |