Animalia: Why Wild Dolphins Walked on Their Tails, Then Stopped

Most people think of dolphins as entertaining, some know them to be intelligent, but sometimes it's neat to look at a more scientific explanation of behavior that we humans anthropomorphize in animals, that is, view their behavior through our own human cultural eyes. An email from the Washington Post touched on some insights of recently developed dolphin behavior and how that behavior might not be just as "fun" behavior but might also include mourning:

By Karin Brulliard 

Tullula, a wild dolphin, tail-walking in Adelaide, Australia. (Whale and Dolphin Conservation) 

Anyone who's visited an aquarium — or seen photos from SeaWorld — knows dolphins at such facilities are good at learning tricks. But so are wild dolphins, and they can learn from each other. 

Researchers working in Adelaide, Australia, have known this for decades, thanks to the bottlenose dolphins that swim the busy, urban waters of the Port River. Starting in the late 80's, they watched as the marine mammals delighted boaters with the aquarium-standard skill of tail-walking. That's when a dolphin rises vertically out of the water and uses its tail to scoot along the surface, forward or backward. 

There was a reason these dolphins were doing this: They had a good teacher. It started with a female dolphin nicknamed Billie, who in early 1998 was rescued from a polluted creek off the river and spent a few weeks rehabilitating in a local dolphinarium. When she was released into the river, she started occasionally tail-walking — just like she'd seen the captive dolphins that were briefly her roommates do. Within a few years, she'd caught the attention of a conservationist named Mike Bossley, who told the Atlantic this week that the sight was "spectacular."

Read "A Once-Captive Dolphin Has Introduced Her Friends to a Silly Trend" (5 Sept 2018)

But more stunning, according to a recent news release from Bossley's organization, the Whale and Dolphin Conservation Center, was that other dolphins picked it up from Billie. By 2011, nine had been observed performing the behavior, WDC said it had become an example not just of a learned cultural behavior, but of a cultural fad. 

What made it a fad, Bossley and other researchers who documented the tail-walking wrote this week in Biology Letters, was that it eventually started to fade. Since the 2014 death of a dolphin dubbed Wave, whom Adelaide Now referred to as "the most prolific tail-walker Port Adelaide has ever seen," just two have been spotted doing this watery moonwalk. (Adelaide Now, however, also reported that Wave's son, Tullula, is the "new star" of this show.) 

The mystery is why the wild dolphins adopted tail-walking. It doesn't help them eat or mate, so what's the point? Fun, maybe — but then again, Wave was seen doing it next to the corpse of one of her offspring, the researchers reported. 

“My wife, Claire, thinks they did it simply because it felt good,” Bossley told the Atlantic. “It might have been a form of artistic or aesthetic performance, like someone dancing — a behavior that has its own intrinsic value to the dolphin, rather than any functional significance.”