Hunting stingrays is risky business, but New Zealand's killer whales have it down. The strategy for landing prey that comes armed with a biological harpoon gun often involves teaming up – yet one large male orca filmed recently in Ruby Bay seems to have mastered ray-hunting on his own. 

The clip was captured by local vlogger Clay Tall Stories, who has been captivated by this predatory behaviour for years. "I have waited my whole life to get footage like this," he says. "The experience left me in awe for days." 

Orcas pass through the South Island's Ruby Bay each year during spring and summer – a time when large eagle rays are particularly abundant in the coastal shallows. According to Tall, the seasonal hunts leave local beaches littered with carcasses, many of which turn up sans the liver.

Killer whales are known to snack on the nutrient-rich livers of their prey elsewhere in the world, but as far as we know, ray-eating is unique to the New Zealand pods. And over the years, the clever cetaceans have learned a variety of tactics to get the job done safely.

"They seem to be very opportunistic here in New Zealand – but also very specialised," says orca biologist Dr Ingrid Visser. 

Because eagle rays are active swimmers, they require a much brawnier hunting approach than other species. To outmanoeuvre the agile animals in sandy alcoves, killer whales will ram full speed ahead and deliver a fatal blow as quickly as possible. "This one was going so fast I could hardly keep up!" says Tall, adding that some rays nearly beached themselves while trying to escape into shallow pools during the event. 

Bottom-dwelling rays, on the other hand, tend to use nearby rocks and very shallow seagrass beds as hideouts. These areas can be tough to navigate, so orcas will carefully pull a lurking ray by its tail, drag it into more accessible water, and then hold it in place until another pod member can come along to do the biting. This tandem hunting behaviour can also serve as important training for young pod members, who might not be experienced enough to know how to avoid a sting. 

While it might seem odd that something as small as a stingray barb could kill a multi-ton predator, such events do happen. Back in the 1990s, one orca's death was caused by a barb to the throat. 

The individual in the recent clip is clearly a ray-hunting veteran, and Tall considers himself extremely lucky to have witnessed such an impressive hunt.

Tall's interest in orcas nearly got him into trouble several years ago: back in 2013, he was reprimanded by the Department of Conservation for getting too close to wild whales with his boat. He emphasises that the Ruby Bay encounter was filmed from afar. 

"I hope people learn from my mistake," he says. "Keep a healthy distance from orcas so they can go about their natural feeding undisturbed. I was flying the drone from the shore, about 50 meters above, fully zoomed in."

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Top header image: Dave Govoni/Flickr