The size and complexity of dolphin brains—a paradox?
Dolphin brain size with respect to body size ranks between that of apes and humans. The hypertrophic auditory structures, the large cerebrum with extended gyrification and the highly cognitive capabilities of toothed whales seem to be in paradoxical contrast to their thin neocortex with a plesiomorp...
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crcambridgeupr:10.1017/s0025315408000738 2024-09-15T18:39:13+00:00 The size and complexity of dolphin brains—a paradox? Huggenberger, Stefan 2008 http://dx.doi.org/10.1017/s0025315408000738 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315408000738 en eng Cambridge University Press (CUP) https://www.cambridge.org/core/terms Journal of the Marine Biological Association of the United Kingdom volume 88, issue 6, page 1103-1108 ISSN 0025-3154 1469-7769 journal-article 2008 crcambridgeupr https://doi.org/10.1017/s0025315408000738 2024-07-31T04:04:38Z Dolphin brain size with respect to body size ranks between that of apes and humans. The hypertrophic auditory structures, the large cerebrum with extended gyrification and the highly cognitive capabilities of toothed whales seem to be in paradoxical contrast to their thin neocortex with a plesiomorphic or paedomorphic cytoarchitecture. The total number of neurons in the delphinid neocortex is comparable to that of the chimpanzee (Primates), but, in relation to body weight, in the magnitude of the hedgehog (Insectivora) neocortex since cetaceans may be able to obtain larger body sizes than terrestrial mammals due to reduced gravitational effects in water. During evolution, dolphins may have increased the computational performance of their cytoarchitectonically ‘simple’ neocortex by a multiplication of relevant structures (resulting in a hypertrophic surface area) instead of increasing its complexity. Based on this hypothesis, I suggest that the evolution of the large dolphin brain was possible due to a combination of different prerequisites based on adaptations to the aquatic environment including the sonar system. The latter facilitated a successful feeding strategy to support an increased metabolic turnover of the brain and led to a hypertrophic auditory system. Moreover, the rudimentary pelvic girdle did not limit brain size at birth. These adaptations favoured the evolutionary size increase of the cerebral cortex in dolphins facilitating highly cognitive capabilities as well as precise and rapid sound processing using a ‘simple’ kind of neocortical cytoarchitecture. Article in Journal/Newspaper toothed whales Cambridge University Press Journal of the Marine Biological Association of the United Kingdom 88 6 1103 1108 |
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Cambridge University Press |
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language |
English |
description |
Dolphin brain size with respect to body size ranks between that of apes and humans. The hypertrophic auditory structures, the large cerebrum with extended gyrification and the highly cognitive capabilities of toothed whales seem to be in paradoxical contrast to their thin neocortex with a plesiomorphic or paedomorphic cytoarchitecture. The total number of neurons in the delphinid neocortex is comparable to that of the chimpanzee (Primates), but, in relation to body weight, in the magnitude of the hedgehog (Insectivora) neocortex since cetaceans may be able to obtain larger body sizes than terrestrial mammals due to reduced gravitational effects in water. During evolution, dolphins may have increased the computational performance of their cytoarchitectonically ‘simple’ neocortex by a multiplication of relevant structures (resulting in a hypertrophic surface area) instead of increasing its complexity. Based on this hypothesis, I suggest that the evolution of the large dolphin brain was possible due to a combination of different prerequisites based on adaptations to the aquatic environment including the sonar system. The latter facilitated a successful feeding strategy to support an increased metabolic turnover of the brain and led to a hypertrophic auditory system. Moreover, the rudimentary pelvic girdle did not limit brain size at birth. These adaptations favoured the evolutionary size increase of the cerebral cortex in dolphins facilitating highly cognitive capabilities as well as precise and rapid sound processing using a ‘simple’ kind of neocortical cytoarchitecture. |
format |
Article in Journal/Newspaper |
author |
Huggenberger, Stefan |
spellingShingle |
Huggenberger, Stefan The size and complexity of dolphin brains—a paradox? |
author_facet |
Huggenberger, Stefan |
author_sort |
Huggenberger, Stefan |
title |
The size and complexity of dolphin brains—a paradox? |
title_short |
The size and complexity of dolphin brains—a paradox? |
title_full |
The size and complexity of dolphin brains—a paradox? |
title_fullStr |
The size and complexity of dolphin brains—a paradox? |
title_full_unstemmed |
The size and complexity of dolphin brains—a paradox? |
title_sort |
size and complexity of dolphin brains—a paradox? |
publisher |
Cambridge University Press (CUP) |
publishDate |
2008 |
url |
http://dx.doi.org/10.1017/s0025315408000738 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0025315408000738 |
genre |
toothed whales |
genre_facet |
toothed whales |
op_source |
Journal of the Marine Biological Association of the United Kingdom volume 88, issue 6, page 1103-1108 ISSN 0025-3154 1469-7769 |
op_rights |
https://www.cambridge.org/core/terms |
op_doi |
https://doi.org/10.1017/s0025315408000738 |
container_title |
Journal of the Marine Biological Association of the United Kingdom |
container_volume |
88 |
container_issue |
6 |
container_start_page |
1103 |
op_container_end_page |
1108 |
_version_ |
1810483611281915904 |