Making a Splash: The Role of Percussive Sounds in Bubble-net Feeding
Faculty Mentor Name
Dr. Stacie Hooper
Research or Creativity Area
Natural Sciences
Abstract
Humpback whales, Megaptera novaeangliae, exhibit complex feeding patterns, behaviors, and a communication system whose complexity reflects human language. In the Gulf of Alaska, some whales work together, using loud vocalizations and rings of bubbles, to herd herring into tight schools using a behavior known as bubble-net feeding. This allows foraging whales to lunge up out of the water from underneath the school to swallow as much prey as possible (Hanser, 2009). This lunging behavior requires close coordination and communication to be successful. In addition to different types of vocalizations, humpback whales also produce percussive sounds that are the result of parts of their bodies hitting the water, including tail slaps, flipper slaps, and breaches. Several functions for these sounds in bubble-net feeding have been proposed (Sharpe, 2001). They could serve as social cues indicating the end of a feeding event, as an emotional outlet, or fulfill some other social function; alternatively, they could be used to stun the fish, leading to more successful feeding events. These hypotheses are not mutually exclusive. We decided to test both of these hypothesized functions and analyzed hours of underwater audio recordings of humpback whales performing bubble-net feeding in the Gulf of Alaska in an effort to identify all occurrences of percussive sounds. We proposed that percussive sounds that occurred during, or 60 seconds prior to or after, a food call sequence were being used to stun prey or coordinate feeding, and that percussive sounds occurring outside of this time window or between feeding events were being used for other social communication. Our results will allow us to better understand the role of percussive sounds in bubble-net feeding.
Making a Splash: The Role of Percussive Sounds in Bubble-net Feeding
Humpback whales, Megaptera novaeangliae, exhibit complex feeding patterns, behaviors, and a communication system whose complexity reflects human language. In the Gulf of Alaska, some whales work together, using loud vocalizations and rings of bubbles, to herd herring into tight schools using a behavior known as bubble-net feeding. This allows foraging whales to lunge up out of the water from underneath the school to swallow as much prey as possible (Hanser, 2009). This lunging behavior requires close coordination and communication to be successful. In addition to different types of vocalizations, humpback whales also produce percussive sounds that are the result of parts of their bodies hitting the water, including tail slaps, flipper slaps, and breaches. Several functions for these sounds in bubble-net feeding have been proposed (Sharpe, 2001). They could serve as social cues indicating the end of a feeding event, as an emotional outlet, or fulfill some other social function; alternatively, they could be used to stun the fish, leading to more successful feeding events. These hypotheses are not mutually exclusive. We decided to test both of these hypothesized functions and analyzed hours of underwater audio recordings of humpback whales performing bubble-net feeding in the Gulf of Alaska in an effort to identify all occurrences of percussive sounds. We proposed that percussive sounds that occurred during, or 60 seconds prior to or after, a food call sequence were being used to stun prey or coordinate feeding, and that percussive sounds occurring outside of this time window or between feeding events were being used for other social communication. Our results will allow us to better understand the role of percussive sounds in bubble-net feeding.
Comments
All co-authors contributed equally towards this project.