Captivating video has been released of a group of orca killer whales attacking two adult grey whales off the coast of California.
The footage was captured using an overhead drone operated by Evan Brodsky, who was out at sea with Monterey Bay Whale Watch.
The rare footage sees a pod of more than 30 orcas attempting to devour the grey orcas alive, over a period of five hours.
The pod appear to circle the stranded grey whales before going in for an attempted kill.
Although is is not uncommon for orcas to attack gray whales, they normally target calves which are far more vulnerable rather than adults as seen here.
Two adult grey whales could be seen swimming in Monterey Bay
Suddenly the pair came under attack by a pod of at least 30 orca killer whales
In this case, it is very early in the season for the orcas to be attacking the calves which have not yet arrived in the region making the attack highly unusual.
Brodsky managed to observe the attack until the gray whales finally split up from the group and managed to swim to shallower waters.
‘Five hours of an attack by over two dozen Bigg’s killer whales on two adult gray whales, and an attempted predation – which was unsuccessful!’ Brodsky wrote excitedly on Facebook.
‘Usually killer whales will hunt gray whale calves as they head up to their northern feeding areas with their moms. But these were not calves: they were huge adult gray whales! The battered gray whales eventually made it to shallow water, and the orcas broke off.
The killer whales could be seen biting into the grey whales in the Pacific Ocean
Monterey Bay Whale Watch captured rare footage of the orcas attacking two adult grey whales
Video shows more than 30 orcas attacking the adult gray whales and attempting to eat them alive
The gruesome attack lasted five hours before the group split
‘In over 30 years of documenting killer whales encounters by this is the FIRST time that such an attack has been documented on adult gray whales in Monterey Bay!!!’ he wrote.
Bigg’s orcas which are also known as transient killer whales, roam the Pacific Northwest and usually feed on other marine mammals rather than other whales, which eat mainly fish.
The video of the attack gives a rare glimpse into the behavior of orcas and their hunting patterns.
‘Transient Killer Whales, the type that we typically see here in Monterey, have a diet of other mammals, making springtime in Monterey Bay a haven for these tactically sound hunters,’ Monterey Bay Whale Watch explained.
They grey whales were seen with visible wounds on the side of their skin during the attack
While orcas are known to attack gray whales, they typically go after the more vulnerable calves, making this attack on adult whales highly unusual
Members of the orca pod appeared to take turns attacking and biting the grey whales
Usually, the mothers and their calves typically remain fairly close to the shore on their migration up the California coast because it’s safer and food is more abundant.
However, as they come across Monterey Bay, the geography makes it harder for them to stay close to the coast.
Orcas hang around the bay waiting to take advantage of the young calves’ vulnerability in deep, open water.
Gray whales can grow up to 49 feet long and weigh up to 90,000 pounds, the National Oceanic and Atmospheric Administration said.
