Analysis of Humpback Whale Food Calls and Hunting Success Rates
Poster Number
15A
Format
Poster Presentation
Faculty Mentor Name
Stacie Hooper
Faculty Mentor Department
Department of Biological Sciences
Abstract/Artist Statement
When foraging on herring in the Gulf of Alaska, some humpback whales (Megaptera novaeangliae) perform a complex behavior known as bubble net feeding. While some whales work together to blow nets of bubbles which corral the herring, and others produce intense low-frequency vocalizations known as food calls. These vocalizations appear to be aimed at the fish to confuse them, other vocalizations produced may serve to coordinate the group so all whales lunge upward at the same time. Food calls are produced in a series of sequences, with the number of food calls varying between sequences; other types of calls are also produced, often at the end of a sequence. Very low frequency rhythmic vocalizations are produced between sequences. Because not all feeding events are successful, we wanted to try to identify the characteristics that differentiate a successful feeding event from an unsuccessful one. Using Audacity sound analysis software, we analyzed recordings from multiple bubble net feeding events. We hypothesized that more calls would be produced in successful feeding events and that the low, rhythmic vocalizations are used to coordinate the behavior, so these should be present in successful events more often. We hypothesized that a specific call type will be used at the beginning of a feeding event, which serves as an initiation sequence; these call types should be present at the start of the series only. Lastly, as the feeding event nears completion, we hypothesized that food calls would be produced more rapidly, which may increase the effectiveness of the vocalizations on the fish, so the inter-signal interval should decrease as the number of food calls in a sequence increases. The results of this study should help us better understand how humpback whales coordinate and complete this behavior and increase our understanding of their complex communication system.
Location
Information Commons, William Knox Holt Memorial Library and Learning Center
Start Date
29-4-2023 10:00 AM
End Date
29-4-2023 1:00 PM
Analysis of Humpback Whale Food Calls and Hunting Success Rates
Information Commons, William Knox Holt Memorial Library and Learning Center
When foraging on herring in the Gulf of Alaska, some humpback whales (Megaptera novaeangliae) perform a complex behavior known as bubble net feeding. While some whales work together to blow nets of bubbles which corral the herring, and others produce intense low-frequency vocalizations known as food calls. These vocalizations appear to be aimed at the fish to confuse them, other vocalizations produced may serve to coordinate the group so all whales lunge upward at the same time. Food calls are produced in a series of sequences, with the number of food calls varying between sequences; other types of calls are also produced, often at the end of a sequence. Very low frequency rhythmic vocalizations are produced between sequences. Because not all feeding events are successful, we wanted to try to identify the characteristics that differentiate a successful feeding event from an unsuccessful one. Using Audacity sound analysis software, we analyzed recordings from multiple bubble net feeding events. We hypothesized that more calls would be produced in successful feeding events and that the low, rhythmic vocalizations are used to coordinate the behavior, so these should be present in successful events more often. We hypothesized that a specific call type will be used at the beginning of a feeding event, which serves as an initiation sequence; these call types should be present at the start of the series only. Lastly, as the feeding event nears completion, we hypothesized that food calls would be produced more rapidly, which may increase the effectiveness of the vocalizations on the fish, so the inter-signal interval should decrease as the number of food calls in a sequence increases. The results of this study should help us better understand how humpback whales coordinate and complete this behavior and increase our understanding of their complex communication system.