MONTEREY, Calif. — Experts say there has been an unprecedented number of killer whale attacks on gray whale calves in the Monterey Bay since April.

There have been at least eight attacks on gray whale calves in the past two weeks, according to Monterey Bay Whale Watch.

On Sunday, the whale watching group captured drone video of an intense attack.

“This video shows the Gray Whale mother trying to hold her calf at the surface, while Killer Whales take turns charging up at the calf from below trying to separate them,” officials said on Facebook.

“But this calf had a heroic and determined mom who protected her calf for over an hour, so that they were able to swim to the safety of the shallows.”

The lead marine biologist, Nancy Black, said only about 10 percent to 20 percent of gray whale calves that experience an attack like that survive — and it is usually because their mom helped them get to shallow water.

The same group of killer whales has been involved in at least of the recent attacks, researchers said.

“This number of attacks is unprecedented, and our Marine Biologists Nancy Black and Alisa Schulman-Janiger theorize that maybe they let the calf go because they have already eaten so many in such a short time period,” the group stated.

Experts said there are more attacks on gray whales in Monterey Bay than anywhere else in the world, but they’ve never seen as many as they have in the past few weeks.