New footage filmed near Te Horo Beach on New Zealand's North Island has revealed yet another feeding display courtesy of the region's famed killer whales – one that involved some upside-down flipping during the predatory pursuit. (You'll want to turn HD on for this one!)


Orcas have long impressed us with their diverse hunting strategies. The whales rank among the most intelligent oceanic predators, and all that brain power has given rise to countless creative tactics for landing difficult meals. Orcas that eats sharks drive their toothy prey towards the surface, while their mammal-eating kin opt for collaboration while on the hunt. In New Zealand, meanwhile, ray-eating killer whales deliver their bites with careful precision so as to avoid damage from their prey's piercing barbs

The whales featured in the Te Horo clip, which was filmed by local drone operator Jayven Moore, are likely a mother-and-calf pair. Specialisation exists even among these ray-eaters, and each individual hunting "play" is passed down to young pod members from familial matriarchs. 

Explaining the predators' behaviour in the footage involves some speculation, but scientists suspect the adult whale's underwater rotations serve a unique purpose.

Just like their shark relatives, many rays enter a catatonic state known as "tonic immobility" when flipped over – and it seems that some New Zealand orcas have learned to induce this condition. By grabbing a ray while swimming upside down, an orca ensures that its target animal will be unable to fight back once the whale rights itself. This "tonic tumbling" has also been observed in whales that prefer to hunt rays in their rocky hideaways: one orca will guide the prey out from its rocky refuge, flip it over and then wait for a second pod member to deliver the kill strike. 

There's some evidence to suggest that orcas deploy the "flipping" tactic when hunting sharks, too. In the late 1990s, a female orca near the Farallon Islands off the coast of San Francisco was observed holding a white shark upside down for 15 minutes. This likely sent the shark into a tonic trance, and the animal eventually suffocated.

The outcome in that Farallon Islands sighting may have been coincidental, but the prevalence of similar observations in ray-hunting orca groups seems to point to a learned behaviour. 

Immobilised prey makes for easier sharing – past studies have found that around 60 percent of captured rays are passed around among pod members. What's more, ray-flipping by adult orcas gives juveniles a risk-free opportunity to engage with potentially deadly prey.

After an eight-minute chase, the orca in Moore's clip held the captured ray in its mouth until the calf – who had been following along but not participating in the hunt – swam over to tuck in. 

Among fish-eating killer whales, it's common for mother orcas to hold salmon in their mouths to allow calves to sample the meal. Presenting a still-living animal to young offspring, however, seems to be unique to the mammal-eating Bigg's (formerly known as "transient") orcas, as well as the shark-and-ray specialists found in the waters of Australia and New Zealand.  

The orcas' upside-down moves may be a recognised hunting tactic, but it's certainly rare to capture them on film – and Moore's sighting hints at the exciting discoveries we have yet to make about orca social behaviour. As a newbie on the drone scene, he considers himself lucky to have observed the predatory encounter. In fact, he may have entirely missed the spectacle if not for the beachgoers who alerted him to the whales' presence offshore. 

"We were on our way back [from a drive] and came across about four or five people on the beach looking out to the water," he told Stuff New Zealand. "Then we spotted the dorsal fins, so decided to put up the drone. I almost wasn't going to bother, but I'm glad I did. It was pretty amazing."

Catch the unedited full clip in Moore's video here:



Top header image: Victoria Hoete-Dodd/Flickr