Thanks to their skilled "tail walking", South Australia's Port River dolphins have made quite a name for themselves. The behaviour involves furiously paddling the flukes to push the body across the water, and while it's become a staple of many captive-dolphin shows, it's rarely seen in the wild.
The footage was filmed recently by dolphin conservationist Jenni Wyrsta during a trip off the coast of Adelaide. What makes her video so interesting is that the Port River dolphins haven't performed their signature trick (at least in front of people) since 2009, when a renowned tail-walking dolphin known as "Billie" died.
"It was a truly spectacular day," Wyrsta says. "Some of them [did] doubles! I have never, ever seen that." Over the course of the trip, at least four dolphins took to their tails, with some hitting dozens of walks in front of human onlookers.
Dr Mike Bossley, who has studied the Port River dolphins for more than 30 years, was also surprised to see this in action once again.
"One of these tail walkers is the young adult female Oriana, and Oriana's mother is Bianca, who is also a tail walker,” he told Adelaide Now. In fact, every individual seen resurrecting the move had parents who'd also mastered it. This suggests we're looking at an example of animals "culturally transmitting" a playful behaviour.
The Port River pod's origin story is a bit hazy, but local scientists trace their tail walking back to Billie, who did a one-month rehabilitation stint at a marine park in the 1980s. During that time, Billie was housed with several captive dolphins who had been trained to walk on their tails.
After being released, Billie may have brought the trick back with her, and other pod members simply followed her lead. It's possible that this could spawn generations of new tail walkers over time – all of them learning the behaviour by mimicking their mothers.
Many youngsters learn to forage and protect themselves in the same way, but it's rare for a species to "teach" behaviours that have nothing to do with such crucial skills.
We don't know what sparked this latest "walk off", but Wystra notes that the pod has been especially social recently. She speculates this could have something to do with an abundance of food in the area. Just like with many other species, dolphins tend to exhibit more play behaviour when the going is easy.
That's just a hunch, but since we have yet to discover any practical use or benefit to tail walking, our best guess is that this pod is simply having fun.
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Top header image: Richard Herbert/Flickr
Whales and Dolphins
Whales and Dolphins
Animal Behaviour
