2026-05-13 ワシントン大学（UW）
Cook Inlet belugas swimming in northern Cook Inlet, near Anchorage, Alaska. Photo: Arial Brewer
＜関連情報＞
- https://www.washington.edu/news/2026/05/13/uw-researchers-decipher-beluga-calls-to-bolster-conservation-efforts/
- https://link.springer.com/article/10.1007/s00265-026-03740-6
- https://pubs.aip.org/asa/jasa/article-abstract/154/5/3487/2925354/Communication-in-Cook-Inlet-beluga-whales
クック湾のシロイルカの鳴き声は、群れの特性、行動、潮汐の状態によって変化する Cook Inlet beluga whale calling varies by group characteristics, behavior, and tidal state
Arial M. Brewer,Amy M. Van Cise,Christopher Garner,Andrea Gilstad,Manuel Castellote,Sarah J. Converse,Kimberly T. Goetz &Andrew M. Berdahl
Behavioral Ecology and Sociobiology Published:07 May 2026
DOI:https://doi.org/10.1007/s00265-026-03740-6
Abstract
Communication allows social species to exchange information among group members. In aquatic environments, acoustic signals are among the most effective forms of communication and are important for many species, including cetaceans. Beluga whales (Delphinapterus leucas) are highly social and vocal, yet little is known about the functionality of their social calls. To examine context-dependent vocal behavior in belugas, we collected passive acoustic data and fine-scale behavioral observations for the endangered Cook Inlet beluga population. The resulting dataset includes 1,720 annotated vocalizations collected over 21 behaviorally encoded encounters. We fit generalized linear mixed models to these data to investigate the effect of behavioral state, group size, calf presence, and tidal state on (1) calling rate (number of calls/minute) and (2) call category (whistles, pulsed calls, combined calls). Belugas were more likely to call when traveling and had higher calling rates during flood tides. Group-level calling rate increased sublinearly with group size, suggesting that individuals called less in larger groups, possibly reflecting increased listening, vocal coordination, or a strategy to avoid acoustic masking. Group calling rate increased before transitions between traveling and milling, suggesting a possible link between communication and behavioral transitions. Whistles were more prevalent when traveling, while pulsed calls were more prevalent when milling. Combined calls occurred only when calves were present, indicating the importance of these calls in communication with calves. Identifying these communication patterns and the contexts in which they occur can enhance our understanding of beluga whale ecology and aid in conservation efforts via passive acoustic monitoring.
Significance statement
We provide the first description of the behavioral, social, and environmental factors associated with vocal communication in an Alaskan beluga whale population. Cook Inlet beluga whales (CIB) exhibit context-dependent shifts in vocal activity as a function of behavior, tidal state, and group size. CIB use whistles while traveling, pulsed calls while milling, and only produce combined calls when calves are present. Additionally, calling rate appeared to increase prior to behavioral transitions in a small number of observed encounters. These patterns may be related to the types of information being transmitted in these specific contexts, as well as aid in the coordination of group dynamics. Understanding these factors not only advances knowledge of beluga communication, and animal communication more generally, but also contributes to the development of passive acoustic methods to monitor habitat use, behavior, and group characteristics.
クック湾のシロイルカのコミュニケーション：鳴き声のレパートリーと商船の騒音による鳴き声のマスキングについて Communication in Cook Inlet beluga whales: Describing the vocal repertoire and masking of calls by commercial ship noise
Arial M. Brewer;Manuel Castellote;Amy M. Van Cise;Tom Gage;Andrew M. Berdahl
The Journal of the Acoustical Society of America Published:November 30 2023
DOI:https://doi.org/10.1121/10.0022516
Many species rely on acoustic communication to coordinate activities and communicate to conspecifics. Cataloging vocal behavior is a first step towards understanding how individuals communicate information and how communication may be degraded by anthropogenic noise. The Cook Inlet beluga population is endangered with an estimated 331 individuals. Anthropogenic noise is considered a threat for this population and can negatively impact communication. To characterize this population’s vocal behavior, vocalizations were measured and classified into three categories: whistles (n = 1264, 77%), pulsed calls (n = 354, 22%), and combined calls (n = 15, 1%), resulting in 41 call types. Two quantitative analyses were conducted to compare with the manual classification. A classification and regression tree and Random Forest had a 95% and 85% agreement with the manual classification, respectively. The most common call types per category were then used to investigate masking by commercial ship noise. Results indicate that these call types were partially masked by distant ship noise and completely masked by close ship noise in the frequency range of 0–12 kHz. Understanding vocal behavior and the effects of masking in Cook Inlet belugas provides important information supporting the management of this endangered population.
