Behavioral Performance and Evolution of Feeding Modes in Odontocetes

Vertebrate evolution has resulted in a diversity of feeding mechanisms. Cetaceans are secondarily derived tetrapods that have returned to a marine habitat. As a result, they display feeding modes that have converged with more basal aquatic vertebrates, but display a diversity of new solutions and ad...

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Bibliographic Details
Main Author: Kane, Emily A.
Other Authors: Marshall, Christopher D.
Format: Others
Language:English
Published: 2010
Subjects:
Ram
RSI
Online Access:http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-463
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spelling ndltd-tamu.edu-oai-repository.tamu.edu-1969.1-ETD-TAMU-2009-05-4632013-01-08T10:41:02ZBehavioral Performance and Evolution of Feeding Modes in OdontocetesKane, Emily A.SuctionRamBelugaPacific white-sided dolphinPilot whalekinematic analysisRSIaperture shapelateral occlusionpursingpressure measurementperformancegap codingancestral state reconstructionVertebrate evolution has resulted in a diversity of feeding mechanisms. Cetaceans are secondarily derived tetrapods that have returned to a marine habitat. As a result, they display feeding modes that have converged with more basal aquatic vertebrates, but display a diversity of new solutions and adaptations. To begin to explore the diversity of feeding adaptations among odontocetes, kinematics of feeding modes and feeding adaptations for belugas (Delphinapterus leucas), Pacific white-sided dolphins (Lagenorhynchus obliquidens), and long-finned pilot whales (Globicephala melas) were characterized. In addition, direct measurements of intraoral pressure were collected to determine maximum suction performance. Characters from these analyses were combined with data for other odontocetes, and were mapped onto a phylogeny of Odontoceti to begin to explore where changes in feeding modes took place. Feeding modes were diverse in belugas, Pacific white-sided dolphins, and pilot whales and included suction, ram, and a combination of both. In general, four phases were observed: (I) preparatory, (II) jaw opening, (III) gular depression, and (IV) jaw closing. Suction was a large component of the prey capture method in belugas and subambient pressures in excess of 100 kPa were generated. Belugas were also capable of lateral lip gape occlusion and anterior lip pursing to form a small anterior aperture. Pacific whitesided dolphins relied on ram to capture prey. However, some degree of pursing and resultant subambient pressure was observed that was likely used to compensate for high ram speeds or for prey manipulation and transport to the esophagus. Pilot whales were more similar to belugas in kinematics, but maintained high approach velocities and did not generate significant suction pressures; suction and ram were used in combination. Belugas and pilot whales appeared to employ hyolingual depression as a primary suction generation mechanism, whereas Pacific white-sided dolphins relied on fast jaw opening. Ancestral state reconstructions indicated that suction feeding capability evolved independently at least six times within Odontoceti. These results indicate the diversity of feeding behaviors in odontocetes and provide directives for future studies on the diversity of feeding in secondarily aquatic mammals.Marshall, Christopher D.2010-07-15T00:12:05Z2010-07-23T21:43:37Z2010-07-15T00:12:05Z2010-07-23T21:43:37Z2009-052010-07-14May 2009BookThesisElectronic Thesistextapplication/pdfhttp://hdl.handle.net/1969.1/ETD-TAMU-2009-05-463eng
collection NDLTD
language English
format Others
sources NDLTD
topic Suction
Ram
Beluga
Pacific white-sided dolphin
Pilot whale
kinematic analysis
RSI
aperture shape
lateral occlusion
pursing
pressure measurement
performance
gap coding
ancestral state reconstruction
spellingShingle Suction
Ram
Beluga
Pacific white-sided dolphin
Pilot whale
kinematic analysis
RSI
aperture shape
lateral occlusion
pursing
pressure measurement
performance
gap coding
ancestral state reconstruction
Kane, Emily A.
Behavioral Performance and Evolution of Feeding Modes in Odontocetes
description Vertebrate evolution has resulted in a diversity of feeding mechanisms. Cetaceans are secondarily derived tetrapods that have returned to a marine habitat. As a result, they display feeding modes that have converged with more basal aquatic vertebrates, but display a diversity of new solutions and adaptations. To begin to explore the diversity of feeding adaptations among odontocetes, kinematics of feeding modes and feeding adaptations for belugas (Delphinapterus leucas), Pacific white-sided dolphins (Lagenorhynchus obliquidens), and long-finned pilot whales (Globicephala melas) were characterized. In addition, direct measurements of intraoral pressure were collected to determine maximum suction performance. Characters from these analyses were combined with data for other odontocetes, and were mapped onto a phylogeny of Odontoceti to begin to explore where changes in feeding modes took place. Feeding modes were diverse in belugas, Pacific white-sided dolphins, and pilot whales and included suction, ram, and a combination of both. In general, four phases were observed: (I) preparatory, (II) jaw opening, (III) gular depression, and (IV) jaw closing. Suction was a large component of the prey capture method in belugas and subambient pressures in excess of 100 kPa were generated. Belugas were also capable of lateral lip gape occlusion and anterior lip pursing to form a small anterior aperture. Pacific whitesided dolphins relied on ram to capture prey. However, some degree of pursing and resultant subambient pressure was observed that was likely used to compensate for high ram speeds or for prey manipulation and transport to the esophagus. Pilot whales were more similar to belugas in kinematics, but maintained high approach velocities and did not generate significant suction pressures; suction and ram were used in combination. Belugas and pilot whales appeared to employ hyolingual depression as a primary suction generation mechanism, whereas Pacific white-sided dolphins relied on fast jaw opening. Ancestral state reconstructions indicated that suction feeding capability evolved independently at least six times within Odontoceti. These results indicate the diversity of feeding behaviors in odontocetes and provide directives for future studies on the diversity of feeding in secondarily aquatic mammals.
author2 Marshall, Christopher D.
author_facet Marshall, Christopher D.
Kane, Emily A.
author Kane, Emily A.
author_sort Kane, Emily A.
title Behavioral Performance and Evolution of Feeding Modes in Odontocetes
title_short Behavioral Performance and Evolution of Feeding Modes in Odontocetes
title_full Behavioral Performance and Evolution of Feeding Modes in Odontocetes
title_fullStr Behavioral Performance and Evolution of Feeding Modes in Odontocetes
title_full_unstemmed Behavioral Performance and Evolution of Feeding Modes in Odontocetes
title_sort behavioral performance and evolution of feeding modes in odontocetes
publishDate 2010
url http://hdl.handle.net/1969.1/ETD-TAMU-2009-05-463
work_keys_str_mv AT kaneemilya behavioralperformanceandevolutionoffeedingmodesinodontocetes
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