If you're happy and you know it and you're a beluga whale, blow some underwater bubbles -- specifically, blowhole drips and mouth rings.
Noonan was curious why the mammals would expel air underwater, when there didn't seem to be a practical purpose for doing so.
After 83 hours over eight years spent observing the marine mammals at Marineland of Canada, in Niagara Falls, Noonan and his fellow researchers now believe that the bubble blowing corresponds to belugas' moods.
"It's an enigmatic and delightful behavior but also a very complex behavior," Noonan told Phys.org.
Nearly all underwater bubbles (97.2 percent, to be specific) are one of four types -- blowhole drips, blowhole bursts, blowhole streams and mouth rings.
Two of these -- blowhole drips and mouth rings -- seem to be primarily playful. As you can see, they also look really, really cool:
Blowhole bursts -- which look like blobs of exhaled air -- seem to be associated with a startle response. Blowhole streams, which are streams of bubbles, indicate aggression in some marine mammals, but Noonan and his team observed the belugas make those streams while swimming together in a friendly way.
There were some sex differences. Female whales made more playful bubbles than did males. Adult females also showed more of a startle response, "which suggests that adult females are more reactive by nature than adult males," Noonan said.
Young male belugas, meanwhile, appeared to be "rowdier" than young females, based on how often they made blowhole bursts.
"For me, the most interesting part was the creativity the beluga whales showed with the bubbles that they later manipulated," Noonan said in an email. "In essence, the whales make their own toys/playthings."
The study is under review at Aquatic Mammals, according to a college spokeswoman.
Lori Marino, a neuroscientist, cetacean expert and founder of the Kimmela Center for Animal Advocacy, cautioned against drawing too many new conclusions from interpretive observations of captive animals.
"Purely descriptive studies in animals kept in severely artificial circumstances are suspect," Marino told The Huffington Post.
As for the implications of this work, the research fits in with a growing body of knowledge showing beluga whales have complex emotional lives, Noonan said.
"Of course that should factor into how we treat them," he said.
And if it's fun to imagine that somewhere out there, a pod of these emotionally complex beluga whales are observing humans, trying to make sense of our odd and sometimes counterintuitive behavior.
"Even in the wild, belugas often approach human boats and human swimmers," Noonan said. "And when they do this, they definitely seem to be checking us out."
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