Drone footage from Monterey Bay Whale Watch showed two adult gray whales fend off an attack from more than 30 orcas.
The attack -- released by the tour agency -- took place in Monterey Bay, Calif., just south of San Francisco, and lasted six hours, according to Evan Brodsky, the employee who captured the footage.
The gray whales survived the attack and ultimately swam to shallower waters.
Throughout spring, gray whales migrate from the coast of Baja California, Mexico, north along the West Coast and Gulf of Alaska, according to the Department of Commerce's National Oceanis and Atmospheric Administration. This journey makes them susceptible to attacks from their main predator -- the killer whale, also known as orcas.
The average Orca weighs between 8,000 and 12,000 pounds, significantly smaller than the average gray whale that can weigh up to 78,000 pounds. What the Orca lacks in weight, however, it makes up for in their sharp teeth, intelligence and swimming speed, placing it at the top of the ocean food chain.
Orcas are known to prey on younger whales, known as calves. However, this early in the migration season made the typically safe adults their target.
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