Drone footage of courting gray whales off the coast of southern California has captured one of the huge mammals moving its tail like a snake, possibly to scare off a nearby dolphin.

The footage, which was shot with a DJI Phantom drone, was taken by Dana Wharf Whale Watching on March 19. The Dana Point encounter happened during the gray whales’ north migration.

In a YouTube post, Dana Wharf Whale Watching explains that the pacific white-sided dolphin may have been pestering the whales. “We have never seen a whale move his tail like a snake, it looks as though the whale is slapping at the dolphin and then you see the dolphin appear again at the top of the whale,” it said.