A new paper published in the journal Biology Letters describes how tail walking was learned by a single bottlenose dolphin and then copied by other dolphins in the same community, and, much like a pop fad, then faded out.
Tail-walking involves a dolphin rising vertically out of the water and then moving forward or backwards across it. Image credit: University of St Andrews.
An adult female dolphin called Billie was rescued from a polluted creek in January 1988, spending several weeks in a dolphinarium, until released back in to the wild.
It seems she learned tail walking by observing the performing dolphins and, when released, began performing this unique behavior with regularity in the wild.
Billie’s tail walking would be nothing more than an interesting example of individual social learning if she alone had performed it, after having observed it during her short time in captivity. Soon other dolphins in the local community began performing the behavior.
By 2011 nine dolphins had been observed tail walking in the wild. After 2011 the number of dolphins tail walking in the wild declined with the most prolific tail-walker dying in 2014, leaving only two remaining tail-walkers, both of whom performed the behavior only sporadically.
Tail walking now seems destined to disappear from the community and thus can be considered a dying fad.
The behavior was tracked using thousands of hours of observation effort by citizen scientists, and its spread suggests a social function for copying in dolphin communities.
“It was only because he had been studying the Adelaide dolphins for over 30 years that the significance of tail walking was recognized,” said lead author Dr. Mike Bossley, from Whale and Dolphin Conservation.
“I knew Billie’s history and was able to track her behavior and that of the other dolphins in the community over an extended period. This enabled me to observe tail walking spread through the community and then its eventual fade away.”
“Once again we see the power of being able to study cetaceans over extended periods that mean something given their lifespans,” said co-author Dr. Luke Rendell, from the University of St Andrews.
“Understanding more about the social transmission of behavior will help us predict how different species may respond to changes in their environment,” said co-author Dr. Philippa Brakes, from Whale and Dolphin Conservation.
“The rapid spread of socially learnt behaviors can operate much faster than the intergenerational process of natural selection, which can be an advantage or a disadvantage, depending on the type of behavior transmitted.”
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Mike Bossley et al. 2018. Tail walking in a bottlenose dolphin community: The rise and fall of an arbitrary cultural ‘fad.’ Biology Letters, in press; doi: 10.1098/rsbl.2018.0314
