Date of Award

Summer 8-2014

Degree Type

Masters Thesis

Degree Name

Master of Arts (MA)

Department

Psychology

Committee Chair

Stan Kuczaj

Committee Chair Department

Psychology

Committee Member 2

Alen Hajnal

Committee Member 2 Department

Psychology

Committee Member 3

Richard Mohn

Committee Member 3 Department

Educational Studies and Research

Abstract

Dolphin communication is multimodal and incorporates physical behaviors and vocalizations. Dolphins often exchange information with conspecifics using different types of vocalizations, and these vocalizations are sometimes associated with specific behaviors. However, the relationship of vocalization type and mouthing behavior type has not been investigated. This thesis examines simultaneous acoustic and visual recordings of bottlenose dolphins (Tursiops truncatus) to determine the relationship between type of mouthing behavior and type of vocalization (whistle, whistle-squawk, chirp, moan, burst-pulse type A, burst-pulse type B, and click trains). The role of the social context of a mouthing behavior is also evaluated. Data were obtained opportunistically from a captive population of bottlenose dolphins at the Roatan Institute for Marine Science from March 2010 through June 2011. Raven Pro 1.4 is used to visually code vocalization types during all instances of each of three mouthing behaviors (mouthing, open mouth and bite/rake) and associated social contexts. Burst-pulse ‘B’ vocalizations are the most frequent. By behavior type, the highest average rate of vocalizations are of whistles during mouthing. By context, the highest average rate of vocalizations are of whistle squawks during aggression. There is a difference in the rate of three frequency-modulated vocalizations across behavior type. When the social context of mouthing behaviors is examined, both pulsed and tonal vocalizations differ in rate. There is also a difference in the rate of several types of whistle contours across behavior type. This study is the first to document a change in frequency and type of vocalization with respect to mouthing behaviors and demonstrates that bottlenose dolphin information exchange during mouthing behaviors is organized and fluid with respect to the social environment.

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