Amazing stuff! Fascinating! I just blogged here about other recent whale song research!
"“They’re all kind of using the same language, but phrasing things slightly differently,” said Mauricio Cantor, assistant professor in OSU’s Marine Mammal Institute and a co-author on the study. Cantor is referring to something called “identity codas” — unique sequences of Morse code-like clicks that serve as symbolic social markers. ...
The researchers l... analyzed over 23,400 sperm whale codas recorded in 23 specific regions in the Pacific spanning from the Galapagos to Tonga, Japan, and Chile. The recordings came were gathered over a course of almost 40 years. ...
The codas are a tell-tale sign of culture, passed down from generation to generation through social learning. When they’re young, calves don’t know any specific codas but they learn them by mimicking the adults and then keep the codas consistent. ...
Whales use these codas differently in different situations. When they know they’re the only clan in a particular geographical area, they use the codas sparingly. But in a crowded area with multiple clans, where the whales don’t exactly know if the nearby whales are part of their clan, they use it more often to distinguish themselves. ..."
The researchers l... analyzed over 23,400 sperm whale codas recorded in 23 specific regions in the Pacific spanning from the Galapagos to Tonga, Japan, and Chile. The recordings came were gathered over a course of almost 40 years. ...
The codas are a tell-tale sign of culture, passed down from generation to generation through social learning. When they’re young, calves don’t know any specific codas but they learn them by mimicking the adults and then keep the codas consistent. ...
Whales use these codas differently in different situations. When they know they’re the only clan in a particular geographical area, they use the codas sparingly. But in a crowded area with multiple clans, where the whales don’t exactly know if the nearby whales are part of their clan, they use it more often to distinguish themselves. ..."
From the abstract:
"... Using acoustic data collected from 23 Pacific Ocean locations, we provide quantitative evidence that certain sperm whale acoustic signals exhibit spatial patterns consistent with a symbolic marker function. Culture segments sperm whale populations into behaviorally distinct clans, which are defined based on dialects of stereotyped click patterns (codas). We classified 23,429 codas into types using contaminated mixture models and hierarchically clustered coda repertoires into seven clans based on similarities in coda usage; then we evaluated whether coda usage varied with geographic distance within clans or with spatial overlap between clans. Similarities in within-clan usage of both “identity codas” (coda types diagnostic of clan identity) and “nonidentity codas” (coda types used by multiple clans) decrease as space between repertoire recording locations increases. However, between-clan similarity in identity, but not nonidentity, coda usage decreases as clan spatial overlap increases. This matches expectations if sympatry is related to a measurable pressure to diversify to make cultural divisions sharper, thereby providing evidence that identity codas function as symbolic markers of clan identity. Our study provides quantitative evidence of arbitrary traits, resembling human ethnic markers, conveying cultural identity outside of humans, and highlights remarkable similarities in the distributions of human ethnolinguistic groups and sperm whale clans."
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