It’s not just humans who have regional accents – dolphins seem to possess their own unique variations too.
The Kiwi accent, renowned for its singularity, has become a hallmark of New Zealand’s national carrier’s marketing strategy, highlighting the challenge of comprehending it. Similarly, dolphins might encounter difficulties in communication when interacting with those residing in other parts of their aquatic domain, as evidence suggests they may exhibit diverse dialects.
Dr. Jessica Patiño-Pérez, hailing from Massey University (New Zealand), meticulously documented the whistles emitted by Tursiops dolphins dwelling near the Great Barrier Island (GBI) along the northern coastline of New Zealand. Meanwhile, recordings from a distinct dolphin population dwelling near Doubtful Sound (DS), situated close to the southern tip of the South Island, were graciously provided by Dr. Marta Guerra from the University of Otago (New Zealand).
Collaborating with her peers, Patiño-Pérez embarked on a comprehensive analysis of these recordings, juxtaposing them with each other and with acoustic data sourced from other dolphin communities across the globe.
Diverse Dolphin Diction
Dolphins, recognized for their highly developed communication skills, utilize an array of sounds to locate sustenance and maintain social cohesion. Whistles, spanning a frequency spectrum from 3,000 to 36,000 Hz and persisting for up to 4 seconds, constitute just one of the triad of vocalizations employed by dolphins in their communication repertoire, as elucidated by IFL Science.
Local environmental conditions can significantly influence whistle patterns: dolphins inhabiting deeper waters tend to produce lower-frequency whistles, contrasting with their counterparts dwelling closer to the coastline, who may emit higher-pitched tones that do not propagate as far. Among dolphins, “signature whistles” serve as distinctive vocal markers believed to function akin to individual names, facilitating identification within social groupings. For the purpose of this study, the team disregarded these signature whistles and focused instead on the communal whistling patterns shared by many or all members of the dolphin pods.
It’s already established that dolphins employ whistles to coordinate group behaviors, recognize conspecifics, and foster social harmony, all of which hinge upon the capacity to decipher the semantic content encoded within specific whistling sequences. Given sufficient temporal isolation, it stands to reason that disparate dolphin populations may evolve distinct vocal dialects, paralleling the diversification observed in human languages.
Can Dolphins from Different Regions Comprehend Each Other?
The temporal duration required for the emergence of mutually unintelligible dialects among distinct dolphin populations remains a subject of conjecture. Genetically, the GBI and DS dolphin populations exhibit considerable divergence, suggesting limited intermingling between them.
This genetic divergence appears to be mirrored in their vocalizations: differences in whistle contour, duration, and terminal frequency were found to be markedly divergent between the two populations. The acoustic characteristics of the whistles recorded by the research team were distinct to such an extent that computational algorithms achieved an accuracy rate of 90% in attributing whistle sets to their respective populations. “Key discrepancies were observed in whistle contour, duration, and terminal frequency,” the researchers noted.
“Whistles from DS displayed prolonged durations and greater inflection points compared to those from GBI. Strikingly, acoustic parameters of New Zealand dolphin populations clustered more closely with those found in the northern hemisphere, rather than their southern hemisphere counterparts,” the authors remarked. This phenomenon could potentially be attributed to historical migration patterns, with dolphins from northern territories contributing to the acoustic landscape of Aotearoa.
Environmental Adaptations and Vocal Variability
Interestingly, despite residing in shallower waters, GBI dolphins were observed to produce lower-frequency whistles, despite considerable overlap in the vocal repertoires of both populations. The researchers speculate that DS dolphins may modulate their vocal pitch in response to fluctuations in the presence of tourist vessels in their habitat.
The extent to which Tursiops dolphins from disparate populations would be able to comprehend each other’s vocalizations, should they come into contact, remains uncertain. Nevertheless, mutual incomprehension could exacerbate geographical segregation among dolphin populations: attempting to establish rapport with a dolphin from an unfamiliar dialect group would prove futile if linguistic barriers obstruct meaningful communication.
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