Biology subjects

Crutchfield, J. P.

Publications and source records attributed to Crutchfield, J. P..

4 recordsLinked to original sources

bioRxiv2023

Whales in Space: Experiencing Aquatic Animals in Their Natural Place with the Hydroambiphone

Recording the undersea three-dimensional bioacoustic sound field in real-time promises major benefits to marine behavior studies. We describe a novel hydrophone array--the hydroambiphone (HAP)--that adapts ambisonic spatial-audio theory to sound propagation in ocean waters to realize many of these benefits through spatial localization and acoustic immersion. Deploying it to monitor the humpback whales (Megaptera novaeangliae) of southeast Alaska demonstrates that HAP recording provides a qualitatively-improved experience of their undersea behaviors; revealing, for example, new aspects of social coordination during bubble-net feeding. On the practical side, spatialized hydrophone recording greatly reduces post-field analytical and computational challenges--such as the "cocktail party problem" of distinguishing single sources in a complicated and crowded auditory environment--that are common to field recordings. On the scientific side, comparing the HAPs capabilities to single-hydrophone and nonspatialized recordings yields new insights into the spatial information that allows animals to thrive in complex acoustic environments. Spatialized bioacoustics markedly improves access to the humpbacks undersea acoustic environment and expands our appreciation of their rich vocal lives.

animal behavior and cognition↗

bioRxiv2023

Twainspotting: Identity Revealed During a Simple, but Extended Conversation with a Humpback Whale

Extended acoustic interactions with a humpback whale (Megaptera novaeangliae) were captured via human-initiated playbacks of the purported humpback "throp" social call and hydrophone recordings of the animals vocalized responses during August 2021 in Frederick Sound, Southeast Alaska. Multivariate statistical analyses performed after the event, that adapted the Wasserstein metric to spectrograms, strongly imply that the played back call was from the same animal, which had been recorded the previous day and initially selected for its clarity. This suggests these interactive playback studies may have formed a probe of time-delayed self-recognition. Fluke photographs taken that previous day and during the interactions revealed that the animal had been identified 38 years earlier, now known as the female humpback named Twain 14 years ago. This exciting and to our knowledge unique series of interactive vocalization events, while hopeful, poses more questions than answers. Most basically, did the half-hour long series of acoustic exchanges constitute an interspecies conversation? We argue that analysis tools available to infer the implied causality of interaction--statistical dependency, multivariate information theory, and machine learning--leave the question open. That said, and perhaps more importantly, the extended interaction broaches questions whose answers bear directly on future interspecies communication and, more generally, the human appreciation of nonhuman intelligence. The reported human-humpback interactions will facilitate exploring these issues at new depths.

animal behavior and cognition↗

bioRxiv2022

A Whale With A History: Sighting Twain The Humpback Over Three Decades

Extended acoustic interactions with a humpback whale (Megaptera novaeangliae) were captured via playbacks of the purported "throp" social call and hydrophone recordings of the animals vocalized responses during August 2021 in Frederick Sound, Southeast Alaska. Fluke photographs identified the animal as a female named Twain (HappyWhale.com identity SEAK-0401) first observed some 38 years ago. We document Twains life history via sightings made over almost four decades. The observational history gives illuminating snapshots of the long history of the individual behind the acoustic interactions.

animal behavior and cognition↗

bioRxiv2021

Using Conspecific Playbacks to Investigate Contact Calling in Southeast Alaskan Humpback Whales

Humpback whales (Megaptera novaeangliae) produce calls across age and sex class and throughout their migratory range. Despite growing interest in calling behavior, the function of most calls is unknown. Among identified call types, the whup is ubiquitous, and innate, and may serve as a contact call. We conducted an acoustic playback experiment combined with passive acoustic monitoring and visual observations to test the function of the whup on a Southeast Alaskan foraging ground. Using a before-during-after design, we broadcasted either a control sound or a unique whup call sequence. We investigated the change in whup rates (whups/whale/10 minutes) in response to treatment (whup or control) and period (before, during, or after). In 100% of the conspecific trials, whup rates increased during broadcasts, and whup rates were significantly higher than in before or after periods. There was no significant difference in whup rates between before and after periods during conspecific trials. In control trials, there were no significant differences in whup rates between before, during, or after periods. Neither whups nor control playbacks elicited an approach response. Humpback whale vocal responses to whup playbacks suggest that whups function as a contact call, but not necessarily as an aggregation signal.

animal behavior and cognition↗