[MARMAM] New Publication

Chris Marshall marshalc at tamug.edu
Mon Jan 27 12:25:06 PST 2014

Dear Colleagues,

I¹d like to bring your attention to a new publication in PLOS ONE:

Marshall, C.D., Marsh A., Wieskotten, S., Kot, B., Hanke W., Hanke, F.,
Dehndardt, G. 2014. Feeding kinematics, suction, and hydraulic jetting
capabilities in harbor seals (Phoca vitulina). PloS ONE, Published January
24, 2014, DOI: 10.1371/journal.pone.0086710.

A PDF of the article can be found at:


The feeding kinematics, suction and hydraulic jetting capabilities of
captive harbor seals (Phoca vitulina) were characterized during controlled
feeding trials. Feeding trials were conducted using a feeding apparatus
that allowed a choice between biting and suction, but also presented food
that could be ingested only by suction. Subambient pressure exerted during
suction feeding behaviors was directly measured using pressure
transducers. The mean feeding cycle duration for suction-feeding events
was significantly shorter (0.15±0.09 s; P<0.01) than biting feeding events
(0.18±0.08 s). Subjects feeding in-water used both a suction and a biting
feeding mode. Suction was the favored feeding mode (84% of all feeding
events) compared to biting, but biting comprised 16% of feeding events. In
addition, seals occasionally alternated suction with hydraulic jetting, or
used hydraulic jetting independently, to remove fish from the apparatus.
Suction and biting feeding modes were kinematically distinct regardless of
feeding location (in-water vs. on-land). Suction was characterized by a
significantly smaller gape (1.3±0.23 cm; P<0.001) and gape angle
(12.9±2.02°), pursing of the rostral lips to form a circular aperture, and
pursing of the lateral lips to occlude lateral gape. Biting was
characterized by a large gape (3.63±0.21 cm) and gape angle (28.8±1.80°;
P<0.001) and lip curling to expose teeth. The maximum subambient pressure
recorded was 48.8 kPa. In addition, harbor seals were able to jet water at
food items using suprambient pressure, also known as hydraulic jetting.
The maximum hydraulic jetting force recorded was 53.9 kPa. Suction and
hydraulic jetting where employed 90.5% and 9.5%, respectively, during
underwater feeding events. Harbor seals displayed a wide repertoire of
behaviorally flexible feeding strategies to ingest fish from the feeding
apparatus. Such flexibility of feeding strategies and biomechanics likely
forms the basis of their opportunistic, generalized feeding ecology and
concomitant breadth of diet.

Thank you,
Christopher Marshall


Christopher D. Marshall, Ph.D.Associate Professor
Department of Marine Biology, and Wildlife and Fisheries Sciences
200 Seawolf Parkway
Building 3029, Room 253
Texas A&M University
Galveston, Texas 77553
Phone: (409) 740-4884
Fax: (409) 740-5001
Email: marshalc at tamug.edu
(please note the difference in the spelling of my last name)

Great things are not done by impulse, but by a series of small things
brought together.
- Vincent van Gogh

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