Whistle use and whistle sharing by allied male bottlenose dolphins, Tursiops truncatus
Watwood, Stephanie Lynn
MetadataShow full item record
LocationSarasota Bay, FL
KeywordBottlenose dolphin; Sound production by animals; Social behavior in animals; Echolocation; Vocalization
Male dolphins form stable, long-term alliances comparable to long-term relationships formed by terrestrial species. The goal of this thesis was to determine the effect of the formation of these alliances on vocal development. Comparing whistles produced in isolation revealed that alliance partners have similar whistles, while non-partners do not. Whistle similarity seen in alliance partners mirrors group-specific vocal convergence in stable groups of birds and bats. Males produce more variable whistles than females, and females have more stable whistle repertoires. Unlike males, females do not maintain the strong, stable relationships seen in male alliances. Increased vocal plasticity in males may be related to modifying whistle production while forming alliances. Females produced whistles that were less similar to other females than to males. Females may rely on whistle distinctiveness for mother-offspring recognition, while males may rely on whistle convergence to maintain specific social bonds. The whistles produced by an isolated individual may not represent its complete repertoire. A hydrophone array was used to record whistles of free-swimming, socializing individuals to compare to the whistles produced by those animals in isolation. There was no significant difference in the whistle repertoires of restrained vs. free-swimming dolphins for over 60% of the animals, and most produced at least one whistle type in both contexts. Therefore, animals use similar whistles in isolated and free-swimming conditions. Recordings of different social groups were examined to test if signature whistles function as contact calls. An allied male produced signature whistles most often when separated from his partner and least often when with his partner. Signature whistles were also highly individually distinctive, and therefore well suited as contact calls, while variant whistles were not. Separations and reunions between alliance partners were examined to determine if whistles are used to maintain contact between preferred associates. Most whistles recorded from separated males were signature whistles. The timing of whistle production was correlated with the timing of the maximum partner separation and the initiation of a reunion. Few whistles were produced as the partners separated. Therefore, whistles may initiate reunions between partners. This thesis demonstrates that free-ranging male dolphins use signature whistles in the same way as females and captive dolphins.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2003
Showing items related by title, author, creator and subject.
Development and functions of signature whistles of free-ranging bottlenose dolphins, Tursiops truncatus Sayigh, Laela S. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1992-09)This thesis presents data on the development and functions of individually distinctive signature whistles of free-ranging bottlenose dolphins, Tursiops tnmcatus. Research was conducted at a study site near Sarasota, ...
Identifying signature whistles from recordings of groups of unrestrained bottlenose dolphins (Tursiops truncatus) Janik, Vincent M.; King, Stephanie L.; Sayigh, Laela S.; Wells, Randall S. (2011-09-29)Bottlenose dolphins (Tursiops truncatus) have individually-distinctive signature whistles. Each individual dolphin develops its own unique frequency modulation pattern and uses it to broadcast its identity. However, ...
King, Stephanie L.; Sayigh, Laela S.; Wells, Randall S.; Fellner, Wendi; Janik, Vincent M. (The Royal Society, 2013-02-20)Vocal learning is relatively common in birds but less so in mammals. Sexual selection and individual or group recognition have been identified as major forces in its evolution. While important in the development of vocal ...