Persistent Effects of Begging on Common Bottlenose Dolphin (Tursiops truncatus) Behavior in an Estuarine Population

Abstract: Human interactions can have negative effects on individuals and populations of dolphins. Quantifying these effects is essential for conservation. Common bottlenose dolphins (Tursiops truncatus) near Savannah, Georgia, have demonstrated some of the highest rates of human interactions worldwide; thus, our aim was to determine if begging by dolphins has become a persistent foraging strategy which subsequently has altered behavioral patterns of the bottlenose dolphins in waters around Savannah. Dolphins were classified as either beggars or non-beggars based on whether they had displayed human-interactive behaviors, such as patrolling, begging, or human-interaction foraging, during their sighting history. Instantaneous and continuous observation sampling during 90-min focal follows were used to collect behavioral data on 17 individual beggars and 16 individual non-beggars. A Pearson’s chi-squared and Kruskal Wallis ANOVA were used to analyze behavioral data. In the time they were observed, beggars spent a significantly smaller percentage of time foraging (26%) compared to non-beggars (45%; p < 0.0001). In contrast, beggars spent significantly more time observed traveling (53%) compared to non-beggars (40%; p < 0.0001). The amount of time they were observed at play, rest, and engaged in social behaviors were similar when comparing beggars and non-beggars (approximately 1% of all behaviors). Boat presence was not a major factor influencing behavioral differences as on average less than one boat, including the research vessel, was within either 10 or 50 m during each focal follow. Thus, the behavioral differences observed are likely indicative of a persistent behavioral shift taking place. Increased interactions with humans not only perpetuate potential further behavioral changes but raise the potential for injuries in dolphins resulting from these human interactions. Health implications for dolphins and their offspring are also a concern as the quality of food received by begging dolphins has not been quantified to determine if a provisioned diet is calorically dense enough for their long-term health.
Key Words: behavioral pattern, human interactions, begging, transitory vs persistent, bottlenose dolphin, Tursiops truncatus
Document Type: Research Article
Page Numbers: 531-541

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