A group of orca whales harassing a blue whale was caught by a drone camera and posted by scientists who study the whales off the Northern California coast. (Credit: Monterey Bay Whale Watch via Facebook)

A rare sight was captured by a drone camera off the coast of Northern California a few weeks ago. The video shows a group of killer whales streaking through the glassy blue water chasing down a solitary blue whale.

The video of the pursuit was posted by Monterey Bay Whale Watch on their Facebook page on May 18.

Killer whales, also called orcas, are known to attack other ocean-dwelling animals including sea lions, squid, octopuses, sea turtles, sharks, rays, fish and seabirds. They weigh up to 6 tons and can grow as long as a school bus, and can even take down other whales.

But orcas don’t typically go after adult blue whales which, according to a recent National Geographic article that highlighted the killer whales stalking and striking the blue whale, the planet’s largest species, which can reach up to a hundred feet long and weigh close to 200 tons.

Monterey Bay Whale Watch, a whale-watching tour business, knows the orca pod that chased down the blue whale.

“While watching Emma’s family group they suddenly came across a Blue Whale in their path! Although Humpbacks stand up to Killer Whales and trumpet blow at them, Blue Whales are easily startled by Killer Whales, and flee the scene!” they wrote on their Facebook page along with the video post.