Gray whale baby tries to climb on mom’s back as hungry orcas close in.

Killer whales have been feasting on gray whale calves recently off Monterey, Calif., after prolonged and vicious attacks witnessed by boaters.

But on Sunday, a gray whale "super mom" wasn't about to give her baby up to a pod of 12 transient killer whales, despite ferocious attempts by the orcas to separate and drown the calf.

The accompanying drone footage, believed to be the first of its kind, shows the killer whales working as a unit to try to steal the calf for a meal – and perhaps to use the attack as a teaching technique for young orcas in the pod. (Footage is best viewed in full screen.)

The top footage, captured by Slater Moore of Discovery Whale Watch, illustrates the dynamics involved in an orca attack. This occurs each spring as transient killer whales use Monterey Bay's steep canyons in which to stage ambush attacks on migrating gray whale cow-calf pairs.

The second video, courtesy of Monterey Bay Whale Watch, shows the end of the struggle and the killer whales swimming away after failing to notch a kill.

In Moore’s footage, momma gray whale is determined to keep the calf's head above water, and this often means placing the calf on her back. Viewers can see several instances where killer whales try to ram and separate baby from mom, whereupon the battle would be won.

Most of this orca pod – a family group with notorious Emma as its matriarch – had already killed and consumed five gray whale calves this season.

On Sunday, however, they encountered a mother gray whale that appears to have been through this kind of battle in the past.

"She does appear to be some kind of super mom, and it could be that this wasn't her first rodeo," Alisa Schulman-Janiger, a whale researcher watched Sunday's dramatic encounter, told GrindTV.

Schulman-Janiger and research partner Nancy Black, owner of Monterey Bay Whale Watch, were watching from the Point Sur Clipper. Schulman-Janiger, who lives in Southern California, had never witnessed a failed killer whale attack on a cow-calf pair. Black had only witnessed this a few times in two-plus decades.

"This was an extraordinary and robust gray whale mom just determined not to lose her calf," Schulman-Janiger said. "She was a world-champion breath holder. She'd stay down for several minutes at a time with no blows, so she could hold her calf's head above water."

In the end, after an ordeal estimated to have lasted about an hour, the gray whales were left alone and last seen swimming toward the coast. The calf, despite being battered at times by orcas, was swimming normally and appeared to be healthy.

Nor was it clear why the killer whales gave up, but Nancy Black told GrindTV on Monday that Emma's group had logged another gray whale calf kill. That makes seven attacks and six kills in 12 days, "an attack frequency that I haven't seen in my 25 years of observing killer whale attacks in Monterey Bay."

More killer whale content from GrindTV

Pod of marauding killer whales turn Monterey Bay into a killing field