In a new study, pelagic thresher sharks were found to stun their prey by slapping them with their scythe-like fin, the Los Angeles Times reported.

Published Wednesday in the journal PLOS One, researchers said the shark will slap a school of sardines in order to stun or, in some cases, kill them. Scientists have always believed the tail was used as a weapon, but it was not scientifically proven until recently being caught on tape.

"This is the holy grail of thresher shark behavioral research," study lead author Simon Oliver, founder of the Thresher Shark Research and Conservation Project, said.

Klemens Gann, a co-author of the study and expert videographer, witnessed the shark's hunting habits in the Philippines' Visayan Islands in 2010.

"Klemens told me, 'we've got a huge bait ball, the sharks are coming in and we think they're hunting,' so I dropped everything and went down to investigate," Oliver said.

The two recorded and studied the shark, which is not aggressive toward humans, and watched it whip its fin over his head slapping at the fish.

"It's very violent, very quick and very dramatic," Oliver said.

The researchers were able to determine the sharks' sizes from their footage and determined that larger sharks could generate quicker whips of their fins. In almost any case, the shark would turn to eat its prey, averaging 3.6 sardines each time.

Oliver said the goal of his work is to help lawmakers come up with policies to protect these sharks, classified as "vulnerable" on the International Union for Conservation of Nature's Red List.

"I had been chasing these animals for five or six years," Oliver said. "If you saw Andy Murray win Wimbledon over the weekend, you know it was a long road to get there and a big relief. I felt that total awe and joy. I've worked in this field for many, many years, and have never seen anything close to this."