Prenatal investment in the subantarctic fur seal, Arctocephalus tropicalis
We investigated prenatal investment in a large sexually dimorphic mammal, the subantarctic fur seal, Arctocephalus tropicalis, on Amsterdam Island in the Indian Ocean. Pups' sex ratio and body mass, body length, and body condition at birth were studied in relation to timing of birth and materna...
Published in: | Canadian Journal of Zoology |
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Canadian Science Publishing
2001
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Online Access: | http://dx.doi.org/10.1139/z01-022 http://www.nrcresearchpress.com/doi/pdf/10.1139/z01-022 |
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crcansciencepubl:10.1139/z01-022 2024-09-15T17:38:49+00:00 Prenatal investment in the subantarctic fur seal, Arctocephalus tropicalis Georges, Jean-Yves Guinet, Christophe 2001 http://dx.doi.org/10.1139/z01-022 http://www.nrcresearchpress.com/doi/pdf/10.1139/z01-022 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 79, issue 4, page 601-609 ISSN 0008-4301 1480-3283 journal-article 2001 crcansciencepubl https://doi.org/10.1139/z01-022 2024-08-22T04:08:44Z We investigated prenatal investment in a large sexually dimorphic mammal, the subantarctic fur seal, Arctocephalus tropicalis, on Amsterdam Island in the Indian Ocean. Pups' sex ratio and body mass, body length, and body condition at birth were studied in relation to timing of birth and maternal characteristics (body length and body condition) during three consecutive breeding seasons. Pups' sex ratio did not differ from unity throughout the pupping period. The sex of the pup was related to neither maternal body length (i.e., maternal age) nor maternal body condition when mating occurred or at parturition (1 year later), which suggests that the sex ratio was not biased toward one sex during gestation. Newborn male pups were heavier and longer than female pups in all years. Longer mothers tended to arrive later in the season regardless of their body condition, and gave birth to heavier pups whatever the sex of the pup. Mothers in good condition gave birth to heavier male pups than mothers in poor condition, but no significant differences were found for female pups, suggesting that the costs of carrying male foetuses is higher than that of carrying female foetuses. Differences in allocation of maternal resources between male and female pups may be due to sex-related differences in body composition, since male pups were heavier than female pups for a given body length at birth. Thus, male and female foetuses may use maternal resources differently, with males growing in length whereas females appear to grow in body mass. The mothers we monitored over 2 consecutive years gave birth to pups that were similar in quality (in terms of birth mass) over years regardless of the sex of the previous pup and the mother's body length, suggesting that individual reproductive value is independent of maternal age. Furthermore, maternal body condition was not affected by the sex of the foetus, suggesting that there is no differential reproductive cost in carrying a male or a female foetus. Interannual differences in pup body size ... Article in Journal/Newspaper Amsterdam Island Canadian Science Publishing Canadian Journal of Zoology 79 4 601 609 |
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Open Polar |
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Canadian Science Publishing |
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crcansciencepubl |
language |
English |
description |
We investigated prenatal investment in a large sexually dimorphic mammal, the subantarctic fur seal, Arctocephalus tropicalis, on Amsterdam Island in the Indian Ocean. Pups' sex ratio and body mass, body length, and body condition at birth were studied in relation to timing of birth and maternal characteristics (body length and body condition) during three consecutive breeding seasons. Pups' sex ratio did not differ from unity throughout the pupping period. The sex of the pup was related to neither maternal body length (i.e., maternal age) nor maternal body condition when mating occurred or at parturition (1 year later), which suggests that the sex ratio was not biased toward one sex during gestation. Newborn male pups were heavier and longer than female pups in all years. Longer mothers tended to arrive later in the season regardless of their body condition, and gave birth to heavier pups whatever the sex of the pup. Mothers in good condition gave birth to heavier male pups than mothers in poor condition, but no significant differences were found for female pups, suggesting that the costs of carrying male foetuses is higher than that of carrying female foetuses. Differences in allocation of maternal resources between male and female pups may be due to sex-related differences in body composition, since male pups were heavier than female pups for a given body length at birth. Thus, male and female foetuses may use maternal resources differently, with males growing in length whereas females appear to grow in body mass. The mothers we monitored over 2 consecutive years gave birth to pups that were similar in quality (in terms of birth mass) over years regardless of the sex of the previous pup and the mother's body length, suggesting that individual reproductive value is independent of maternal age. Furthermore, maternal body condition was not affected by the sex of the foetus, suggesting that there is no differential reproductive cost in carrying a male or a female foetus. Interannual differences in pup body size ... |
format |
Article in Journal/Newspaper |
author |
Georges, Jean-Yves Guinet, Christophe |
spellingShingle |
Georges, Jean-Yves Guinet, Christophe Prenatal investment in the subantarctic fur seal, Arctocephalus tropicalis |
author_facet |
Georges, Jean-Yves Guinet, Christophe |
author_sort |
Georges, Jean-Yves |
title |
Prenatal investment in the subantarctic fur seal, Arctocephalus tropicalis |
title_short |
Prenatal investment in the subantarctic fur seal, Arctocephalus tropicalis |
title_full |
Prenatal investment in the subantarctic fur seal, Arctocephalus tropicalis |
title_fullStr |
Prenatal investment in the subantarctic fur seal, Arctocephalus tropicalis |
title_full_unstemmed |
Prenatal investment in the subantarctic fur seal, Arctocephalus tropicalis |
title_sort |
prenatal investment in the subantarctic fur seal, arctocephalus tropicalis |
publisher |
Canadian Science Publishing |
publishDate |
2001 |
url |
http://dx.doi.org/10.1139/z01-022 http://www.nrcresearchpress.com/doi/pdf/10.1139/z01-022 |
genre |
Amsterdam Island |
genre_facet |
Amsterdam Island |
op_source |
Canadian Journal of Zoology volume 79, issue 4, page 601-609 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z01-022 |
container_title |
Canadian Journal of Zoology |
container_volume |
79 |
container_issue |
4 |
container_start_page |
601 |
op_container_end_page |
609 |
_version_ |
1810475496393146368 |