Prey Capture
Behavior
Jeffrey Guertin & Amber McCammon
Study Methods
Anatomical studies
 Biomechanical modeling of feeding
apparatus
 Cineradiography
 Electromoyography
 High-speed photography
 Observation
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Skeletal Anatomy of Fish
www.sju.edu
Ancestral Sharks - Amphistylic
• Palatoquadrate articulates with the postorbital
process of the braincase (as does the
hyomandibula) and the ethmoid part of the
braincase.
www.sju.edu
Modern Galean Sharks - Hyostylic
• Palatoquadrate hangs from
the hyomandibula and the
ethmoid part of the braincase.
• Little or no
ligamentous
attachment to
Skull
• ~ decoupled
visceral arches
www.sju.edu
Batoid - Euhystylic
No cranial-palatoquadrate articulation
 Hyomandibula sole support
 Hyoid arch broken - no connection to ceratohyal
 Cranial muscles control
hyoid and lower jaw
depression
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 “Hydrodynamic tongue”
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www.sju.edu
Advantage of Jaw Protrusion
• Fierce suction develops
 Mouth volume - water
and prey forced into mouth
• Extension of bite, more
efficient bites & manipulation of
prey
• ~ Assist in jaw closure
jpgallposters.com
http://www.amnh.org/learn/pd/fish_2/fish_skull/skull_movie_two.html
Structure and Function of the Teeth
• Seizing/grasping ~ small, multiple rows of lateral cusplets
• Tearing ~ long & pointed w/ narrow cusps
• Cutting ~ bladelike, one fully erect functional row
• Crushing ~ low, cutting edges w/ bluntly rounded apices
• Grinding ~ imbricated flattened teeth that form dental plate
typepad.com
Structure and Function
of the Teeth
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# of tooth rows varies
Homodont teeth are rare
Replacement rate species specific
Different replacement rates - species and seasonality
Sexual heterodonty in many elasmobranchs
Aetobatus narinari - lower jaw teeth move anteriorly
out of the crushing zone and remain attached to the
tooth plate to form a spadelike appendage used to dig
up prey items.
© Cathleen Bester
Senses useful in Prey Capture
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Olfaction: detect 1ppb, ~ important than sight &
sound
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Shark repellents don’t work in combination with food
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Gustation: Taste papillae - epithelial lining of mouth &
pharynx. on roof than on floor
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Sight: light & movement sensitive
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cones ~ see in color
Tapetum lucidum
Pupil can dilate and contract
Clear water ~ 15 m
Royal Cornwall Museum
Senses useful in Prey Capture
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Sound: attracted to low-frequency pulsed
sounds ~25 to 100 Hz, distances as great as
250 m (820 ft.).
Lateral line: senses low-frequency vibrations distance perception directional water flow.
 Ampullae of Lorenzini: sense bioelectrical
fields in final stages of prey capture.
 Sensory pit: ~ sense organ not olfactory
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Prey Capture Methods
Ram Feeding
 Biting
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 Pin
& Pivot
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• Fish
• Marine Mammals
John Harding
Nationalgeographic.com
..
Functional Morphology
Elasmobranchs Specialized for Ram Prey Capture
Large
mouth
Large teeth
Prey Capture Methods
Suction
 Filter Feeding
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QuickTime™ and a
TIFF (U ncompressed) decompressor
are needed to see this picture.
Stephen Frink
• Benthic invertebrates
• Fish
• Plankton
John Harding
Functional Morphology
Elasmobranchs Specialized for
Suction Prey Capture
Small
Stephen Frink
mouth
Small teeth
Mouth enclosed
Rapid buccal
expansion
Feeding
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Prey Capture
Manipulation/processing bites
Hydraulic transport
Charles Maxwell
Swallowing methods not fully understood
Capture Behavior
Speculation
 Ambushing
 Stalking
 Lure
 Scavenge
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The Scourge-VIMAS
Forage Tactics
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Solitary
Aggregations
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Cooperative herding
Feeding Frenzies
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Not necessarily cooperative foraging - attractive site
Nationalgeographic.com
Feeding Location and Prey Capture
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Surface feeding
 Above
or below surface head raise
 Continuous ram
 Pulsatile suction
Go to
http://www.gianttarpon.com/sh
arkbroad.htm
elasmodiver.com
Feeding Location and Prey
Capture
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Mid-water feeding
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Head-on approach
Side roll approach
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QuickTime™ and a
TIFF (U ncompr ess ed) dec ompres sor
ar e needed to s ee this pi ctur e.
Bite and spit
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Filter
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Qu ickTime™ an d a
TIFF (U ncom pre sse d) de com pre ssor
are nee ded to s ee th is p icture.
f.chtah.com
Feeding Location and Prey
Capture
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Bottom feeding
 Attack
and stun
 Benthivorous
 Biting
 Suction
Go to
http://www.youtube.com/wa
tch?v=68TDbKX4-6o
elasmodiver.com
Future Studies of Elasmobranch
Prey Capture Behavior
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Rays & Skates
Olfactory response
Mechanics of cutting
Feeding mechanism - jaw protrusion
New techniques for functional morphologists
and behavioral ecologists
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Electromyography
High-speed photography
 Pressure displacement measurements
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References:
Carrier, J.C., Musick, J.A., Heithaus, M.R., 2004. Biology of sharks
and their relatives. CRC Press, pp. 165-202.
Chapman, D.D., Gruber, S.H., 2002. A further observation of the
prey-handling behavior of the great hammerhead shark, Sphyrna
mokarran: predation upon the spotted eagle ray, Aetobatus narinari.
Bulletin of Mar. Sci. 70(3): 947-952.
Compagno, L.J.V., 1988. Sharks of the order Carcharhiniformes.
Princeton University Press, pp. 64-68.
Dean, M.N., Wilga, C.D., Summers, A. P., 2005. Eating without
hands or tongue: specialization, elaboration and the evolution of prey
processing mechanisms in cartilaginous fishes. Biol. Lett. 1, 357361.
Ferry-Graham, L.A., 1998. Effects of prey size and mobility on preycapture kinematics in leopard sharks Triakis semifasciata. The J. of
Exp. Biol. 201, 2433-2444.
Gilbert, P.W., 1963. Sharks and survival. D.C. heath and Co., pp.
255-282.
Hamlett, W. C., 1999. Sharks, skates, and rays-the biology of
elasmobranch fishes. The Johns Hopkins University Press,
110.pp.107-110.
Humann, P., Deloach, N., 2003. Reef fish behavior, Florida,
Caribbean, Bahamas. New World Publications, Inc., 300-309.
Questions?
ywww.ri.net/schools/East_Greenwich
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naturalhistorymag.com
.johneasleyStephen Frink
Hooklessthejohnharding.comBait.jpg
elasmodiver
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National geo