Acoustic Patterns and Foraging Efficiency: Identifying Success-Linked Vocalizations in Humpback Whale Bubble Net Feeding
Faculty Mentor Name
Dr. Stacie Hooper
Research or Creativity Area
Natural Sciences
Abstract
Known for their migratory patterns and intricate vocalizations, humpback whales (Megaptera novaeangliae) also exhibit complex social cooperation. This is best seen in ‘bubble-net feeding, a highly coordinated group behavior used to efficiently corral and consume prey. During this behavior, one whale emits bubbles, while others use loud frequency-modulated vocalizations called food calls to force the fish closer together and towards the surface (Sharpe, 2001). If successful, all the whales in the group open their mouths at once to consume the fish (Hanser, 2009). The whales may also be using food calls to help coordinate the group’s behavior. The structure of food calls was defined fairly specifically by early observers (Cerchio & Dahlheim, 2001) but they acknowledged that there may be other types of food calls being used. During our analysis of vocal recordings of humpback whales performing bubble-net feeding in the Gulf of Alaska, we noticed the presence of certain call types during feeding events. We had previously thought these calls were social in function as they did not strictly match the food call descriptions from the literature. These call types, described by our group as, ‘sea lion’ (similar to a sea lion bark), high cries (high frequency harmonically-structured calls), and trills (long, highly modulated calls), appear to occur at varying points in a food call sequence. We hypothesized that these three call types are used by the whales in conjunction with other food calls to increase foraging efficiency, either by increasing coordination or improving manipulation of the fish. Either way, we expect feeding events which utilize these additional call types will be more successful than feeding events that occur without them.
Acoustic Patterns and Foraging Efficiency: Identifying Success-Linked Vocalizations in Humpback Whale Bubble Net Feeding
Known for their migratory patterns and intricate vocalizations, humpback whales (Megaptera novaeangliae) also exhibit complex social cooperation. This is best seen in ‘bubble-net feeding, a highly coordinated group behavior used to efficiently corral and consume prey. During this behavior, one whale emits bubbles, while others use loud frequency-modulated vocalizations called food calls to force the fish closer together and towards the surface (Sharpe, 2001). If successful, all the whales in the group open their mouths at once to consume the fish (Hanser, 2009). The whales may also be using food calls to help coordinate the group’s behavior. The structure of food calls was defined fairly specifically by early observers (Cerchio & Dahlheim, 2001) but they acknowledged that there may be other types of food calls being used. During our analysis of vocal recordings of humpback whales performing bubble-net feeding in the Gulf of Alaska, we noticed the presence of certain call types during feeding events. We had previously thought these calls were social in function as they did not strictly match the food call descriptions from the literature. These call types, described by our group as, ‘sea lion’ (similar to a sea lion bark), high cries (high frequency harmonically-structured calls), and trills (long, highly modulated calls), appear to occur at varying points in a food call sequence. We hypothesized that these three call types are used by the whales in conjunction with other food calls to increase foraging efficiency, either by increasing coordination or improving manipulation of the fish. Either way, we expect feeding events which utilize these additional call types will be more successful than feeding events that occur without them.
