PHOTOS: Sharks, Marine Mammals Hang In Paradise
Clearly this method works, and it's more efficient than hunting fish one by one. Sardines are on the small side, so a predator could quickly run out of steam trying to chase a single fish, and then another and another.
Most fish species are on the decline, due to overfishing, pollution and other human-caused problems, so the hunting method is increasingly important for sharks.
"This extraordinary story highlights the diversity of shark hunting strategies in an ocean where top predators are forced to adapt to the complex evasion behaviors of their ever declining prey," said Oliver in a press release.
The tail slaps might also help sharks to communicate with each other, although that hasn't been proven yet. Humpback and sperm whales slap their tails a lot, turning them into a sort of oceanic Morse code to communicate over long distances.
Photo: A Bigeye thresher shark swims near Cocos Island National Park in Costa Rica.