Date of Award

2009

Document Type

Thesis

Degree Name

Bachelors

Department

Social Sciences

First Advisor

Harley, Heidi

Keywords

Dolphin, Phonation, Vocalization, Synchrony

Area of Concentration

Psychology

Abstract

Bottlenose dolphins (Tursiops truncatus) have a complex system of acoustic communication that includes several broadly constructed categories of phonations: echolocation clicks, whistles, burst pulses, and jaw claps. The structure of this system is still largely mysterious to humans. Social organization among these large brained mammals is also complex. For example, calves' period of dependency on their mothers is protracted, and adults maintain varied-strength associations with many individuals across a wide community. Understanding these multifaceted relationships is of ongoing interest. One measure of social relationships in the dolphin is synchronous behavior. Although never previously studied, an understanding of the way in which phonations are related to synchrony might reveal insights both into dolphin acoustic communication and into social organization. To that end, the current study investigated phonation production rates of 4 male captive dolphins in relation to synchrony. Analysis included 11 five-minute simultaneously recorded audio and video files collected throughout a day. Sound files were coded for phonation type and producer(s), when possible; videos were coded for synchronous swimming. The analyses revealed that synchrony was common (28% sampling time) and individual participation levels varied. For example, 1 of the 4 dolphins participated in 90% of the synchronous bouts, another in fewer than 30%. Burst pulses and jaw claps, commonly correlated with aggression, were never produced by synchronous dolphins. In files that contained some synchrony, whistles and clicks occurred at lower rates during synchrony than during periods of non-synchrony. However, rates were lowest in base rate samples in which no synchrony ever occurred. Further analyses investigated the use of specific whistle frequency contours including the dolphins' signature whistles, contours typically classified at cohesion calls. Whistles were not reliable predictors of synchrony. Overall, phonations did vary in relation to synchrony suggesting that this line of research if worth pursuing in order to learn more about how phonations and social behaviors interact.

Rights

This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.

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