Orcas are well equipped to handle just about anything they meet in the water, but one pod off the coast of British Columbia recently encountered an oddball: an antlered buck. 

The strange scene was caught on camera by skipper and wildlife photographer Mark Malleson, who – despite years of sailing these waters – had never seen anything like it. Malleson is also a research assistant with Fisheries and Oceans Canada, so the sighting quickly piqued his interest. 

After crossing paths with four Bigg's (or "transient") orcas, a group known to feed primarily on marine mammals, Malleson spotted the deer cruising near his boat. 

"I was sort of excited to think I could be one of the first people to photo-document a hunt [of this kind]," he told CBC News. "Unfortunately, there was no predation. Well, fortunately for the deer ... but unfortunately for the photo-op."

Malleson had heard rumours of such events playing out in neighbouring Alaska, but wasn't sure of their authenticity.

In fact, it's not implausible that terrestrial grazers might feature in the diets of these North American predators. British Columbia alone is surrounded by over 100 coastal islands, and deer occasionally swim between them in search of greener pastures or breeding opportunities. 

"The whales would have passed by him within a hundred metres," Malleson told Earth Touch. "I suspect they did know he was there but chose to continue on."  

On land, deer can clock speeds verging on 40 mph (64 kph), but that number drops to just 13mph (20 kph) in the water – that's certainly slower than seals, dolphins or porpoises, which are more typical mammalian prey for orcas.

While individual orca groups have unique dietary preferences, 11 million years on this planet have shaped them into skilled opportunistic hunters as well. It's not entirely surprising that a mammal-eating group would take advantage of the odd off-the-menu cut. Birds and otters have also been found in Bigg's killer whale stomachs (but despite their far-ranging appetites, it's worth noting that not a single attack by wild orcas on humans exists on record).

Anecdotal evidence of venison-eating orcas dates all the way back to 1961, when Canadian fishery officers reportedly observed a predation near Jackson Bay on the central coast. And according to National Marine Mammal Laboratory biologist Marilyn Dahlheim, who has published a book on the killer whales of Southeast Alaska, a pod near Gustavus managed to take down a cow moose and her calf in 2010. On her blog, The Marine Detective, humpback researcher Jackie Hildering points out that divers found a submerged deer carcass off Vancouver Island some two years later. Lacerations on that animal's body looked consistent with an orca bite, but it's impossible to say with certainty what killed it.

"It seemed so intact, fated and out of place," Gary Marcuse, one of the divers, told Earth Touch via email. "I had to touch the hide to believe it. A large jaw had bitten through the soft viscera and even removed a couple of ribs on the forward edge of the bite. The image of a swimming deer finding itself in the jaws of an orca came to us immediately."

Gary Marcuse examines the carcass. Images: Rob Roy/used with permission

Wolves and other terrestrial predators could be to blame, but it's also possible that this deer simply died of natural causes close to shore, and washed out to sea.

"It was a very small island," notes Marcuse. So the odds of a deer and a wolf [together there] seems remote, but possible."

As for Malleson's buck, after the whales had moved along, the skipper ushered the lone male to shore with his Zodiac boat. "It seemed as though he was disoriented as he was getting well offshore," he said. "I felt the deer wouldn't have made it back without drowning, so I trolled along 50 to 100 metres behind him until he reached the shore and climbed out." 



Top header image: Tim Nutt, Flickr