A brutal gang attack on a tiger shark by killer whales has revealed the violence of orcas in all its gruesome detail.
The footage, which is believed to be a world-first, shows three killer whales working as a team to force the panicked shark to the surface.
The gang wear the shark down and take opportunistic bites at its fins, until a large bull moves in to deliver the death blow, flipping the shark on to its back in the process.
This creates a state of paralysis known as ‘tonic immobility’. The pod then takes turns at eating and stripping the 7ft (2.1 metres) shark down to its bare bones before disappearing back into the ocean.
The brutal footage was captured off the coast of Costa Rica by underwater photographer Caroline Power and British marine biologist Nicholas Bach.
Ms Power, 26, who filmed the footage from a dive boat, said: ‘I have been lucky enough to witness some amazing things in and on the ocean – but this was unbelievable.
‘I believe this is the first time orcas hunting tiger sharks has been documented – we were all fairly awestruck.
‘After the orcas had left we all just kind of stood in the boat, staring at the ocean, contemplating what we had seen.
‘The tiger shark is the top predator in those waters, so to see it knocked off the top of the food chain, to see it afraid, to see it fight for its life and lose was pretty incredible.’
There were three killer whales from the pod involved in the attack, while another female and her new calf – estimated to be just two weeks old – hung back from the action.
Ms Power and Mr Bach, 34, originally from London, had witnessed the same pod kill a hammerhead shark just a few days before.
On that occasion, a female swam past with the spinal remains of the shark hanging from the corner of its mouth.
The killer whale pod would even approach the filmmakers at close-quarters when out diving and, despite their power, the couple found them to be ‘inquisitive, graceful and simply awe-inspiring’.
But the following day they witnessed a more ferocious side during the tiger shark ambush – which unfolded at Chatham Bay on Cocos Island earlier this month.
Ms Power, who is from Baton Rouge, Louisiana, but now lives in Roatan, Honduras, was nearing the end of a diving trip on board the Dive Live-aboard Undersea Hunter boat with Mr Bach and other guests when the whales appeared.
She said: ‘All of a sudden the fin of the bull orca popped out of the water about thirty feet from the boat. We could see him and a few other orcas swimming.
‘It was raining and fairly choppy so it was hard to tell exactly what was happening from the boat.
‘Due to the Cocos Island National Park regulations we were not allowed to get into the water with the orcas. This is probably a very good thing as quite quickly I saw the fin of a shark break the surface and the water started churning. Then all of the fins disappeared and the water stilled.
‘The shark resurfaced about 15ft (4.5 metres) from the boat with the orcas in hot pursuit.
‘Unable to get into the water, I did the next best thing and put my mask on and stuck my head into the water. What looked somewhat peaceful on the surface looked anything but from underwater.
Ms Power described how the large bull and two females were swimming rapidly around the shark, trapping it against the surface and trying to ram into it.
‘You could see the shark was exhausted and injured. It was desperately dodging attack after attack from the orcas but was tiring and they were not,’ she said.
‘The shark made one last attempt to use the boat as shelter and as it swam straight at me I could almost see the desperation in its black eyes.
‘I lifted my head and camera out of the water just before his razor-sharp teeth could grab me. It then started biting the side of the boat, working itself around before attacking the engines as well. I think he wanted to get into the boat.
‘The water then erupted one last time with what must have been the fatal blow. Then it all went calm.’
She added: ‘We had drifted from shore by this point and were in deeper water.
‘I stuck my head back in the water and the orcas were just under the boat, playing with the dead shark.
Ms Power claimed the orcas easily could have eaten it in a few bites. Instead, she says, they toyed with it, like a cat does with a dead mouse.
They bit the fins off and took turns rolling their streamlined catch through the water, taking a small bite.
‘This went on for a while until all that was left was the tail and spine. The orcas then swam slowly out into the blue, the remains of the former king of Chatham Bay firmly in the female’s mouth.’
According to local experts, the tiger shark population of Chatham Bay has grown in the last seven years with many coming to feast on newborn boobie birds, which often land in the ocean on their first attempt at flying.
The orcas are seen every September but usually stay for just a few days. It is believed they only stayed in this area longer than usual because one of the females had just given birth.
