Amateur video captured near Campbell River earlier this week shows northern resident killer whales displaying rare behaviour on the beach that has scientists excited.

Chris Wilton filmed the orcas rubbing their bellies on stones in Dog Bay in the Discovery Islands and called the sighting a “once in a lifetime experience”.

“It was mind-blowing, breath-taking. I was in complete awe,” Wilton told CTV News. “Everything stopped, you know … I feel very, very blessed that I got to see something like that.”

Scientists agree, saying this “rubbing” doesn’t just happen anywhere. Carla Crossman, a research biologist at the Vancouver Aquarium, said this beach is not one where this behaviour is commonly seen. She said the orcas are very selective about the beaches they rub on and usually choose areas with smooth stones about an inch in size.

“We don’t know why they’re doing it, but they’re very picky,” she said, adding, “It’s very specific. This population of northern residents is one of the only populations in the world in which we see this behaviour.”

Wilton hopes the video helps politicians appreciate the value of keeping these waters protected. “I think all politicians - Harper included - should maybe take a look at this video and realize that these waters should be protected. They shouldn’t have tankers running through here.”

The rubbing action is only seen in a few places between Vancouver and Alaska, and scientists aren’t sure of its purpose.

“It’s probably something social,” Crossman said. “Maybe kind of a ritualistic behaviour because they’re very specific in the beaches that they go to. They get really excited coming into these beaches. We see them kind of jumping up a little bit more, squealing, and making a lot of noise underwater.”

Though the rubbing looks like the orcas could be scratching their bodies, Crossman says that is unlikely. “If they were trying to shed off dead skin or maybe exfoliate their skin, we would expect to see it in other populations,” she said.

Crossman said these habits are passed down from generation to generation and while whales used to do this historically, they haven’t in a long time. Such uncommon behaviour makes it difficult for researchers to study.

Anyone who captures similar behaviour is encouraged to pass it along to the B.C. Cetaceans Sightings Network at or 1-866-I-SAW-ONE (1-866-472-9663).

With files from CTV Vancouver’s Peter Grainger