Southern California resident Steve O'Toole has been volunteering on whale-watching trips for about nine years, but he had never seen anything like this.
As the whale-watching boat he was on began driving away from a pod of offshore bottlenose dolphins last Sunday, O'Toole saw that the dolphins were playing and leaping in and out of the boat's wake -- as usual. But one in particular caught his eye.
"As it leapt out of the water, it started to twist its body along its longitudinal axis, like a ballerina," he said in a phone interview with The Huffington Post.
A naturalist and an amateur photographer, O'Toole trained his camera on the twirling dolphin and kept snapping. At 8 frames per second, his Canon 7D captured the animal as water spun off its body, creating a hula-hoop-like effect.
"The first thought that came to my mind was [it looked like] a tutu," said O'Toole. "But through popular demand and social media, it became the 'hula hoop' dolphin."
O'Toole posted the picture on his personal Facebook account later that day. On Tuesday it was picked up by Dana Wharf Whale Watch, the company he was volunteering with when he took the photo. The company posted the picture on its Facebook page and called the image the "Dolphin Hula Hoop."
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Photo by Steve O'Toole
Leaping and spinning are normal behaviors for bottlenose dolphins, according to Alexis Rudd, a PhD candidate at the Hawai'i Institute of Marine Biology.
"Sometimes spinning and leaping behaviors can be associated with trying to knock off animals like remoras that are catching a free ride on the dolphin, but sometimes not," Rudd wrote in an email to HuffPost. "The most likely scenario is that this photographer just got incredibly lucky with the combination of leaping behavior, wave action and photo timing."
O'Toole, who lives in Aliso Viejo, Calif., is a member of the American Cetacean Society, a whale conservation group dedicated to teaching the public about whales and dolphins. He's also on the board of the Orange County chapter of the organization.
He isn't a marine biologist by training, but a lifelong fascination with the sea and his passion for learning have resulted in past jobs at the Pacific Whale Foundation in Hawaii, where he was one of a handful of people without a degree working as a naturalist on the organization's vessels.
By day, he works as a marketer teaching retail associates about his clients' products. But on the weekends, O'Toole is most likely found on one of several whale-watching boats off Dana Point, volunteering his free time to teach tourists and residents everything he knows about the marine life they see.
"I briefly looked at my camera when I was there, and I knew I had something special in it," said O'Toole. "It just shows that that Mother Nature constantly surprises us with awe and wonder."