Graduation Year

2008

Document Type

Dissertation

Degree

Ph.D.

Degree Granting Department

Psychology

Major Professor

Toru Shimizu, Ph.D.

Co-Major Professor

David Mann, Ph.D.

Keywords

Vision, Sensory-integration, Prey, Cephalofoil, Elasmobranch

Abstract

The goal of this dissertation was to further examine the visual system and its importance to the bonnethead shark (Sphyrna tiburo). This species of hammerhead shark possesses the least amount of lateral cephalofoil expansion. Better understanding of their visual system and potential visually-mediated behaviors may increase understanding regarding adaptive benefits of their unique head shape. The dissertation revealed four factors regarding this species’ visual system: 1) the extent of their optical visual fields span between 68-72 degrees laterally and cover their visual horizon, 2) they possess a fairly large (approximately 112 degree) blind spot directly in front of their cephalofoil, 3) they possess an average of 35 degrees of lateral head movement during sinusoidal swimming which likely increase the lateral extents of their optical visual fields, and 4) they can detect and show interest in small visual stimuli resembling their preferred prey species, the blue crab.

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