More than 1,000 common dolphins stampede, as shown in video screen grab.

More than 30 transient killer whales have gathered in Monterey, Calif., to ambush baby gray whales migrating up the coast with their moms.

But the notorious orcas are also known to snack on common dolphins, and the accompanying footage reveals the frantic "stampeding" behavior dolphins exhibit when they suddenly find themselves surrounded by the ferocious black-and-white cetaceans.

Capt. Michael Sack of Sanctuary Cruises captured the extraordinary footage last week while alone on an exploratory trip, on a morning when high winds were in the forecast.

About 1,000 dolphins were alerted to the presence of the killer whales the moment one of them breaches in an attack on a member of the dolphin pod.

"They got one, now they know," an excited Sack says in the video. "Oh man, stampede! That was insane! That was crazy!"


Killer whale surfaces near the dolphins. Photo: Courtesy of Michael Sack/Sanctuary Cruises

The stampede occurs during the first 1:22, after which is mostly the aftermath of the kill.

There's no fighting back among the dolphins, who are overmatched despite their numbers. The best strategy is simply to flee as quickly as possible.

In this case, it seemed as though only one kill was made, in what might have been a case of older killer whales teaching the younger orcas how to hunt.


Two of more than 30 killer whales that are feeding on marine mammals in Monterey Bay. Photo: Courtesy of Michael Sack/Sanctuary Cruises

"What an incredible encounter I just had," Sack says. "Too bad nobody else was out here."

Nancy Black, a researcher and owner of Monterey Bay Whale Watch, said that the gathering of transient killer whales this early in the season is the strongest since 2004.

Gray whale calves are the top menu choice for these killer whales because of their high fat content, compared to dolphins.

So far this season, Black said, three attacks on gray whales have been documented. In 2004, in a season that typically runs through May, 16 attacks on gray whales were documented, although not all were successful.

Common dolphins are considerably more abundant off Southern California, but for the past few years they've been showing in Monterey Bay, far north of their typical range.

They’re also preyed upon frequently by transient killer whales, but as Sack says in the video description: “There’s rarely someone there with their video camera focused and waiting for it to happen.”

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