A pod of orcas in Canada created quite the spectacle last month when they ventured into shallow waters at a local pebble beach near British Columbia's Campbell River. The behaviour displayed in the video is known as 'rubbing', and though some experts attribute it to the need for a bit of beach-pebble exfoliation, others suggest there may be more to it.

 "This is the A42 group – a group of Northern resident killer whales," Vancouver Aquarium research biologist Carla Crossman tells CTV News. "We see them rub on these beaches, and [we think] it’s probably something social – maybe a kind of ritualistic behaviour – because they’re very specific in [choosing] which beaches they go to. If they were trying to shed off dead skin, we would expect to see it in other populations."

Though this is the first instance of rubbing witnessed at this particular site, Crossman suspects that previous generations of the pod visited it. "They get really excited coming into 'their' beaches," she says. "We see them jumping more, squealing and they make a lot of noise underwater."

Interestingly, there are many cultural differences between the salmon-eating resident orca pods and the 'transient' orcas that prey on marine mammals. In fact, the two groups rarely interact, even when they traverse the same waters within days, or even hours, of each other! 

The rubbing behaviour is rarely seen, so researchers are excited that so many smartphone-wielding citizens were there to document it!

Top header image: Bob Jensen/Flickr