An Unparalleled Sexual Dimorphism of Sperm Whale Encephalization
The sperm whale Physeter macrocephalus (Linnaeus, 1758) is the largest toothed whales and possesses the highest absolute values for brain weight on the planet (together with the killer whale Orcinus orca). Former calculations of the encephalization quotient (EQ), which is used to compare brain size...
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ftunivpadovairis:oai:www.research.unipd.it:11577/3219003 2024-02-11T10:05:30+01:00 An Unparalleled Sexual Dimorphism of Sperm Whale Encephalization COZZI, BRUNO MAZZARIOL, SANDRO Podestà, Michela ZOTTI, ALESSANDRO Huggenberger, Stefan Cozzi, Bruno Mazzariol, Sandro Podestà, Michela Zotti, Alessandro Huggenberger, Stefan 2016 ELETTRONICO http://hdl.handle.net/11577/3219003 https://doi.org/10.46867/IJCP.2016.29.00.01 http://escholarship.org/uc/item/4jv59569 eng eng University of California USA volume:29 numberofpages:9 journal:INTERNATIONAL JOURNAL OF COMPARATIVE PSYCHOLOGY http://hdl.handle.net/11577/3219003 doi:10.46867/IJCP.2016.29.00.01 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85090272411 http://escholarship.org/uc/item/4jv59569 info:eu-repo/semantics/openAccess Encephalization Quotient sperm whale brain size sexual dimorphism in the brain social evolution info:eu-repo/semantics/article 2016 ftunivpadovairis https://doi.org/10.46867/IJCP.2016.29.00.01 2024-01-24T17:44:51Z The sperm whale Physeter macrocephalus (Linnaeus, 1758) is the largest toothed whales and possesses the highest absolute values for brain weight on the planet (together with the killer whale Orcinus orca). Former calculations of the encephalization quotient (EQ), which is used to compare brain size of different mammalian species, showed that the sperm whale brain is smaller than expected for its body mass. However, the data reported in the literature and formerly used to calculate the sperm whale EQ suffered from a potential bias due to the tendency to measure mostly larger males of this extreme sexually dimorphic species. Accordingly, we found that the brains of female sperm whales are close to the absolute weight range of the males, but, given the much lower body mass of females, their EQ results more than double of what reported before for the whole species, and is thus nearly into the primate range (female EQ = 1.28, male EQ = 0.56). This sexual dimorphism is unique among mammals. Female sperm whales live in large families in which social interactions and inter-individual communication are essential, while adult males live solitarily. Thus the particular sex-specific behavior of SWs may have led to a maternally-driven social evolution, and eventually contributed to achieve female EQ values (but not male EQs) among the highest ever calculated for mammals with respect to their large body mass. Article in Journal/Newspaper Killer Whale Orca Orcinus orca Physeter macrocephalus Sperm whale toothed whales Killer whale Padua Research Archive (IRIS - Università degli Studi di Padova) International Journal of Comparative Psychology 29 |
institution |
Open Polar |
collection |
Padua Research Archive (IRIS - Università degli Studi di Padova) |
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ftunivpadovairis |
language |
English |
topic |
Encephalization Quotient sperm whale brain size sexual dimorphism in the brain social evolution |
spellingShingle |
Encephalization Quotient sperm whale brain size sexual dimorphism in the brain social evolution COZZI, BRUNO MAZZARIOL, SANDRO Podestà, Michela ZOTTI, ALESSANDRO Huggenberger, Stefan An Unparalleled Sexual Dimorphism of Sperm Whale Encephalization |
topic_facet |
Encephalization Quotient sperm whale brain size sexual dimorphism in the brain social evolution |
description |
The sperm whale Physeter macrocephalus (Linnaeus, 1758) is the largest toothed whales and possesses the highest absolute values for brain weight on the planet (together with the killer whale Orcinus orca). Former calculations of the encephalization quotient (EQ), which is used to compare brain size of different mammalian species, showed that the sperm whale brain is smaller than expected for its body mass. However, the data reported in the literature and formerly used to calculate the sperm whale EQ suffered from a potential bias due to the tendency to measure mostly larger males of this extreme sexually dimorphic species. Accordingly, we found that the brains of female sperm whales are close to the absolute weight range of the males, but, given the much lower body mass of females, their EQ results more than double of what reported before for the whole species, and is thus nearly into the primate range (female EQ = 1.28, male EQ = 0.56). This sexual dimorphism is unique among mammals. Female sperm whales live in large families in which social interactions and inter-individual communication are essential, while adult males live solitarily. Thus the particular sex-specific behavior of SWs may have led to a maternally-driven social evolution, and eventually contributed to achieve female EQ values (but not male EQs) among the highest ever calculated for mammals with respect to their large body mass. |
author2 |
Cozzi, Bruno Mazzariol, Sandro Podestà, Michela Zotti, Alessandro Huggenberger, Stefan |
format |
Article in Journal/Newspaper |
author |
COZZI, BRUNO MAZZARIOL, SANDRO Podestà, Michela ZOTTI, ALESSANDRO Huggenberger, Stefan |
author_facet |
COZZI, BRUNO MAZZARIOL, SANDRO Podestà, Michela ZOTTI, ALESSANDRO Huggenberger, Stefan |
author_sort |
COZZI, BRUNO |
title |
An Unparalleled Sexual Dimorphism of Sperm Whale Encephalization |
title_short |
An Unparalleled Sexual Dimorphism of Sperm Whale Encephalization |
title_full |
An Unparalleled Sexual Dimorphism of Sperm Whale Encephalization |
title_fullStr |
An Unparalleled Sexual Dimorphism of Sperm Whale Encephalization |
title_full_unstemmed |
An Unparalleled Sexual Dimorphism of Sperm Whale Encephalization |
title_sort |
unparalleled sexual dimorphism of sperm whale encephalization |
publisher |
University of California USA |
publishDate |
2016 |
url |
http://hdl.handle.net/11577/3219003 https://doi.org/10.46867/IJCP.2016.29.00.01 http://escholarship.org/uc/item/4jv59569 |
genre |
Killer Whale Orca Orcinus orca Physeter macrocephalus Sperm whale toothed whales Killer whale |
genre_facet |
Killer Whale Orca Orcinus orca Physeter macrocephalus Sperm whale toothed whales Killer whale |
op_relation |
volume:29 numberofpages:9 journal:INTERNATIONAL JOURNAL OF COMPARATIVE PSYCHOLOGY http://hdl.handle.net/11577/3219003 doi:10.46867/IJCP.2016.29.00.01 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-85090272411 http://escholarship.org/uc/item/4jv59569 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.46867/IJCP.2016.29.00.01 |
container_title |
International Journal of Comparative Psychology |
container_volume |
29 |
_version_ |
1790602565255168000 |