| Summary: | Humpback whales, Megaptera novaeangliae, are known for their complex vocal and social behavior. Some whales engage in a cooperative foraging behavior known as bubble net feeding. During bubble net feeding, humpbacks work together in groups using nets of bubbles and complex vocalizations to capture fish. Food calls are powerful, low frequency vocalizations produced in long sequences, along with other complex calls, to signal other whales, help corral the fish into a specific area, and possibly even stun the fish. We analyzed hours of audio recordings collected from whales performing bubble net feeding in the Gulf of Alaska using Audacity sound analysis software. In our analysis of multiple food call sequences, we noticed that not all feeding events were successful, and that often there was more than one whale producing food calls and/or social calls during foraging events (referred to as duets). We hypothesized that successful feeding events would contain more duets, either because the initial caller becomes fatigued during a sequence and needs another caller to take over, or because duets increase the efficacy of the calls produced through temporal summation of the signal. It is also possible that duets are used to coordinate lunges into the school of fish at the end of a feeding event; these hypotheses are not mutually exclusive. To test our hypotheses, we identified where duets occurred in a series of food call sequences, which call types were produced by multiple callers simultaneously, and whether one caller resumed vocalizing to complete the sequence, all with respect to the success of each feeding event. Our results should help us better understand how whales coordinate this complex behavior, and the role of specific call types, such as food calls, in performing it.
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