Architecture of the sperm whale forehead facilitates ramming combat
Herman Melville's novel Moby Dick was inspired by historical instances in which large sperm whales (Physeter macrocephalus L.) sank 19th century whaling ships by ramming them with their foreheads. The immense forehead of sperm whales is possibly the largest, and one of the strangest, anatomical...
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ftunivqespace:oai:espace.library.uq.edu.au:UQ:384151 2023-05-15T17:59:29+02:00 Architecture of the sperm whale forehead facilitates ramming combat Panagiotopoulou,Olga Spyridis, Panagiotis Mehari Abraha, Hyab Carrier, David R. Pataky, Todd C. 2016-04-05 https://espace.library.uq.edu.au/view/UQ:384151 eng eng PeerJ doi:10.7717/peerj.1895 issn:2167-8359 orcid:0000-0002-6457-448X Connective tissue partitions Finite element analysis Probabilistic simulation Ramming impact Sperm whale Spermaceti junk 1100 Agricultural and Biological Sciences 1300 Biochemistry Genetics and Molecular Biology 2700 Medicine 2800 Neuroscience Journal Article 2016 ftunivqespace https://doi.org/10.7717/peerj.1895 2020-12-22T11:52:57Z Herman Melville's novel Moby Dick was inspired by historical instances in which large sperm whales (Physeter macrocephalus L.) sank 19th century whaling ships by ramming them with their foreheads. The immense forehead of sperm whales is possibly the largest, and one of the strangest, anatomical structures in the animal kingdom. It contains two large oil-filled compartments, known as the ``spermaceti organ'' and ``junk,'' that constitute up to one-quarter of body mass and extend one-third of the total length of the whale. Recognized as playing an important role in echolocation, previous studies have also attributed the complex structural configuration of the spermaceti organ and junk to acoustic sexual selection, acoustic prey debilitation, buoyancy control, and aggressive ramming. Of these additional suggested functions, ramming remains the most controversial, and the potential mechanical roles of the structural components of the spermaceti organ and junk in ramming remain untested. Here we explore the aggressive ramming hypothesis using a novel combination of structural engineering principles and probabilistic simulation to determine if the unique structure of the junk significantly reduces stress in the skull during quasi-static impact. Our analyses indicate that the connective tissue partitions in the junk reduce von Mises stresses across the skull and that the load-redistribution functionality of the former is insensitive to moderate variation in tissue material parameters, the thickness of the partitions, and variations in the location and angle of the applied load. Absence of the connective tissue partitions increases skull stresses, particularly in the rostral aspect of the upper jaw, further hinting of the important role the architecture of the junk may play in ramming events. Our study also found that impact loads on the spermaceti organ generate lower skull stresses than an impact on the junk. Nevertheless, whilst an impact on the spermaceti organ would reduce skull stresses, it would also cause high compressive stresses on the anterior aspect of the organ and the connective tissue case, possibly making these structures more prone to failure. This outcome, coupled with the facts that the spermaceti organ houses sensitive and essential sonar producing structures and the rostral portion of junk, rather than the spermaceti organ, is frequently a site of significant scarring in mature males suggest that whales avoid impact with the spermaceti organ. Although the unique structure of the junk certainly serves multiple functions, our results are consistent with the hypothesis that the structure also evolved to function as a massive battering ram during male-male competition. Article in Journal/Newspaper Physeter macrocephalus Sperm whale The University of Queensland: UQ eSpace PeerJ 4 e1895 |
institution |
Open Polar |
collection |
The University of Queensland: UQ eSpace |
op_collection_id |
ftunivqespace |
language |
English |
topic |
Connective tissue partitions Finite element analysis Probabilistic simulation Ramming impact Sperm whale Spermaceti junk 1100 Agricultural and Biological Sciences 1300 Biochemistry Genetics and Molecular Biology 2700 Medicine 2800 Neuroscience |
spellingShingle |
Connective tissue partitions Finite element analysis Probabilistic simulation Ramming impact Sperm whale Spermaceti junk 1100 Agricultural and Biological Sciences 1300 Biochemistry Genetics and Molecular Biology 2700 Medicine 2800 Neuroscience Panagiotopoulou,Olga Spyridis, Panagiotis Mehari Abraha, Hyab Carrier, David R. Pataky, Todd C. Architecture of the sperm whale forehead facilitates ramming combat |
topic_facet |
Connective tissue partitions Finite element analysis Probabilistic simulation Ramming impact Sperm whale Spermaceti junk 1100 Agricultural and Biological Sciences 1300 Biochemistry Genetics and Molecular Biology 2700 Medicine 2800 Neuroscience |
description |
Herman Melville's novel Moby Dick was inspired by historical instances in which large sperm whales (Physeter macrocephalus L.) sank 19th century whaling ships by ramming them with their foreheads. The immense forehead of sperm whales is possibly the largest, and one of the strangest, anatomical structures in the animal kingdom. It contains two large oil-filled compartments, known as the ``spermaceti organ'' and ``junk,'' that constitute up to one-quarter of body mass and extend one-third of the total length of the whale. Recognized as playing an important role in echolocation, previous studies have also attributed the complex structural configuration of the spermaceti organ and junk to acoustic sexual selection, acoustic prey debilitation, buoyancy control, and aggressive ramming. Of these additional suggested functions, ramming remains the most controversial, and the potential mechanical roles of the structural components of the spermaceti organ and junk in ramming remain untested. Here we explore the aggressive ramming hypothesis using a novel combination of structural engineering principles and probabilistic simulation to determine if the unique structure of the junk significantly reduces stress in the skull during quasi-static impact. Our analyses indicate that the connective tissue partitions in the junk reduce von Mises stresses across the skull and that the load-redistribution functionality of the former is insensitive to moderate variation in tissue material parameters, the thickness of the partitions, and variations in the location and angle of the applied load. Absence of the connective tissue partitions increases skull stresses, particularly in the rostral aspect of the upper jaw, further hinting of the important role the architecture of the junk may play in ramming events. Our study also found that impact loads on the spermaceti organ generate lower skull stresses than an impact on the junk. Nevertheless, whilst an impact on the spermaceti organ would reduce skull stresses, it would also cause high compressive stresses on the anterior aspect of the organ and the connective tissue case, possibly making these structures more prone to failure. This outcome, coupled with the facts that the spermaceti organ houses sensitive and essential sonar producing structures and the rostral portion of junk, rather than the spermaceti organ, is frequently a site of significant scarring in mature males suggest that whales avoid impact with the spermaceti organ. Although the unique structure of the junk certainly serves multiple functions, our results are consistent with the hypothesis that the structure also evolved to function as a massive battering ram during male-male competition. |
format |
Article in Journal/Newspaper |
author |
Panagiotopoulou,Olga Spyridis, Panagiotis Mehari Abraha, Hyab Carrier, David R. Pataky, Todd C. |
author_facet |
Panagiotopoulou,Olga Spyridis, Panagiotis Mehari Abraha, Hyab Carrier, David R. Pataky, Todd C. |
author_sort |
Panagiotopoulou,Olga |
title |
Architecture of the sperm whale forehead facilitates ramming combat |
title_short |
Architecture of the sperm whale forehead facilitates ramming combat |
title_full |
Architecture of the sperm whale forehead facilitates ramming combat |
title_fullStr |
Architecture of the sperm whale forehead facilitates ramming combat |
title_full_unstemmed |
Architecture of the sperm whale forehead facilitates ramming combat |
title_sort |
architecture of the sperm whale forehead facilitates ramming combat |
publisher |
PeerJ |
publishDate |
2016 |
url |
https://espace.library.uq.edu.au/view/UQ:384151 |
genre |
Physeter macrocephalus Sperm whale |
genre_facet |
Physeter macrocephalus Sperm whale |
op_relation |
doi:10.7717/peerj.1895 issn:2167-8359 orcid:0000-0002-6457-448X |
op_doi |
https://doi.org/10.7717/peerj.1895 |
container_title |
PeerJ |
container_volume |
4 |
container_start_page |
e1895 |
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1766168298516381696 |