Interactive Bioacoustic Playback As a Tool for Decoding Humpback Whale Language

Humpback Whale Acoustics Research
Southeast Alaska, Alaska
August 1st - 15th, 2023

Research Team

  • Jodi Frediani
  • Josephine Hubbard, Ph.D.
  • Debbie Kolyer
  • Lisa Walker

Project Overview

The WhaleSETI team’s mission is the study of animal communication and intelligence, a mandate which fits within SETI’s mission to lead humanity's quest to understand the origins and prevalence of life and intelligence in the universe and share that knowledge with the world. Among the most diverse and complex of animal communication systems are the songs and social sounds of humpback whales. By studying these loquacious creatures and applying information theory to their acoustic signals and conducting adaptive dynamic acoustic playbacks, we aim to uncover the degree to which whale communication exhibits the type of complexity that underlies the power of human communication including that of language and music. Identifying this communicative complexity in humpback whales is just the first step in characterizing the unique cognitive prowess of these animals. Using humpback whales as a proxy, our goal is to develop rigorous methodology that serves as an intelligence filter for all forms and modalities of communication that exist on the Earth and beyond. Humpbacks are great proxies for these goals due in part to their ecology, a result of a complete immersion in watery worlds that may have similar ecological homologs to the media in which interstellar signals travel. These animals have also evolved to communicate over long distances, implicating their astute ability to efficiently package complex information to distant conspecifics. Furthermore, humpback whales show unique behaviors that indicate an interest in interacting with and/or communicating with humans (e.g., mugging). Our findings will help to define intelligence from a non-anthropocentric perspective and thus inform our search for intelligent life in the universe.

Duration of Project

Two years

Expedition Summary

Humpbacks' vocal repertoire includes lengthy, rhythmic, and ever-evolving songs, and a panoply of less studied social sounds, including at least 40 unique social calls. A subclass of these calls shows stability across generations and ocean basins, a prerequisite for the evolution of complex communication. This large and diverse repertoire represents a unique opportunity to characterize and interact with a remarkable nonhuman intelligence, underscored by their gregarious nature and complex, collective behavior. In the study area, humpbacks assemble into teams characterized by division of labor, role fidelity, tool use and enduring bonds between non-kin. The humpback’s loquacious and gregarious nature, as well as spending 90% of its time out of sight underwater, has made it difficult to isolate the vocal stream of individuals and categorize their sounds for syntactical analysis.

The International SeaKeepers Society facilitated a multi-discipline research expedition centered around humpback whale acoustics and vocalizations. The expedition took place over 14 days in August, in Southeast Alaska aboard DISCOVERY Yacht, Blue Pearl, a 65' Fleming owned and operated by Don and Denise Bermant. The trip made its way through Frederick Sound and Chatham Strait, where we successfully photographed and identified 94 individual humpback whales. During the voyage, we lowered a hydrophone (underwater microphone) into the water and listened, observed, and recorded all the vocalizations and sounds emitted by the whales under a variety of contexts. Our set-up included two computers, three software packages, and a hydrophone and underwater speaker system. Signal processing capabilities included the ability to record and manipulate vocalizations in near real time allowing us to experiment with different dynamic playback techniques including time and pitch stretching
of signals. By deploying on the back deck of the Blue Pearl, we were able to closely observe the whales' behaviors and adapt our playback stimulus accordingly. We conducted playbacks on multiple occasions, capturing vocalizations during a wide range of behaviors, including krill feeding and herring bubble netting. Additionally, we documented in-air vocalizations such as trumpets, thrums and wheezy blows, collected fluke IDs and measured the sonic footprint of our vessel at particular distances and trajectories to better understand its acoustic impact on the animals.

Application

The tools and techniques we developed with respect to real time signal capture and manipulation can be applied to dynamic playback systems for other species. The underwater and in-air vocalizations give us deeper insight into humpbacks’ social sounds and how they communicate underwater and perhaps through the air. With a comprehensive analysis, the data we collected will contribute to our goal of bridging the gap between our species’ systems of communication and those of others to advance our understanding of nonhuman communication and intelligence both on Earth and beyond.

Location

Southeast Alaska (Frederick Sound and Chatham Strait)

Photo Gallery & Video

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