Salutations,
I'm pleased to announce a new paper, which presents evidence supporting an
alternative theoretical framework for understanding the vocal behavior of
humpback whales.
Mercado, Eduardo, III (2021) Spectral interleaving by singing humpback whales:
Signs of sonar
Journal of the Acoustical Society of America, 149, 800-806.
Abstract
The duplex sonar model of humpback whale song proposes that broadband units
within songs function differently from narrowband units. Specifically, this
model suggests that singing humpback whales interleave constant frequency (CF)
units, which can generate prolonged reverberation focused at specific
frequencies, with less reverberant broadband units that minimally overlap with
the focal frequencies of preceding and following CF units (referred to as
spectral interleaving) to increase the efficacy of song as a sonar source.
Here, it is shown that singers recorded off the coast of Hawaii in 2015 devoted
most of their time singing to spectrally interleaving broadband elements of
units around quasi-CF components that consistently generated persistent
reverberant tails. Singers maintained reverberant CF streams in specific
frequency bands when units contained broadband elements and when singers
switched from producing pairs of alternating reverberant units to producing a
single reverberant unit. Additionally, singers showed the ability to flexibly
control where acoustic energy was concentrated within broadband components in
ways that minimized spectral overlap with the focal frequencies of reverberant
tails. The consistency and precision with which singing humpback whales
interleaved broadband and reverberant CF elements of units confirm two novel
predictions of the duplex sonar model.
Cheers,
Eduardo Mercado III
Professor
Department of Psychology; Ecology, Evolution, & Behavior Program
University at Buffalo, SUNY
Buffalo, NY
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