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First published online September 16, 2005
Journal of Experimental Biology 208, 3721-3730 (2005)
Published by The Company of Biologists 2005
doi: 10.1242/jeb.01807

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Feeding kinematics of Kogia and Tursiops (Odontoceti: Cetacea): characterization of suction and ram feeding

Brian Bloodworth and Christopher D. Marshall^*

Texas A&M University at Galveston, 5007 Avenue U, Galveston, TX 77551, USA

View larger version (12K): [in a new window]   Fig. 1. Experimental setup. (A) Kogia at MML and (B) Tursiops at SeaWorld of Texas. All videotaping was conducted from the lateral perspective. Note the 1 m squares for Kogia videotaping to maintain a relatively constant distance to subject.

View larger version (14K): [in a new window]   Fig. 2. Kinematic landmarks. (A) Tursiops digitized points identified from footage; (B) Tursiops spatial model within the motion analysis software; (C) Kogia digitized points from video footage and (D) Kogia spatial model. Points include (1) maxilla tip, (2) corner of mouth, (3) mandibular tip, (4) food, (5) center of eye, (6) rostral border of externally apparent hyoid and (7) cranial pectoral fin insertion.

View larger version (21K): [in a new window]   Fig. 3. Kogia and Tursiops feeding near the beginning of the observed feeding cycle and at maximum gape. (A) Kogia preparatory phase with minimal gape; (B) phase II ending with maximum gape. (C) Tursiops closed gape approach; feeding begins with slight gape, tucked pectoral fin and forward motion and (D) overtakes prey at maximum gape. (E) Tursiops open gape approach enters the frame at or near maximum gape, continues forward motion with open gape and (F) closes jaws as prey is overtaken.

View larger version (28K): [in a new window]   Fig. 4. Profiles of key kinematic variables in Kogia and Tursiops as a percentage of total feeding cycle duration: gape, gular depression, gular retraction and prey distance. Gular retraction is scaled along the right y-axis and all other variables on the left y-axis. (A) Kinematic profile of Kogia. (B) Kinematic profile of Tursiops closed gape approach. (C) Kinematic profile of Tursiops open gape approach (gular retraction is not depicted). Feeding phases I-IV (preparatory, jaw opening, gular depression and jaw closing) are denoted below each graph. Kogia and Tursiops closed gape approach display similar patterns in gular depression and retraction, gape and prey distance relative to the onset of each feeding phase; however, Kogia kinematics occurred at a much faster rate. Tursiops open gape approach included a notably delayed gular depression phase onset as a result of slow gape increase. Note gular return to baseline following completion of the feeding cycle.