To capture fish, bottlenose dolphins have many special tricks. They can round them up by disturbing the sediment on the seafloor, creating “mud nets,” or may chase fish toward the shore, trapping their prey before also partially beaching themselves and chowing down.

The cetaceans also have a slightly more brutal tactic: Smacking or flipping fish with their tail flippers, sending them flying into the air. The dolphins then swim over to the stunned fish for an easy bite.

This technique, which has been observed among several types of dolphins in areas as disparate as the U.S. Gulf Coast and New Zealand, has the fancy technical name of “fish-kicking” or “fish-whacking,” explains Stefanie Gazda, a biologist at the University of Florida who studies the animals at Cedar Key, north of Tampa Bay.

Self-proclaimed animal lover Michael McCarthy has been watching bottlenose dolphins do this for years near his home in Seminole, Florida, about a hundred miles to the south. He says that it’s the most common feeding technique that he observes among local bottlenoses—and his recent video of the phenomenon provides new insights into the behavior for people who aren’t lucky enough to live near the animals.

McCarthy filmed the behavior while seated in one of the transparent boats made by his company, SeeThroughCanoe, and captured through the zoom lens of a GoPro mounted on a drone.

“It’s very spectacular video” that clearly shows this fish-whacking, Gazda says, adding the behavior is likely learned by dolphins from their parents or other adults.

But it has also clearly arisen independently several different times, as it’s seen in many areas, she says—an intriguing example of how a successful hunting strategy can evolve in multiple places.

Shannon Gowans, a behavioral ecologist who studies the animals at Eckerd College in St. Petersburg, says she sees the behavior often. “It doesn’t seem to be every individual doing it,” she says, but rather a few key dolphins do it quite a lot. (Related: Dolphin filmed hunting with ‘net’ made of mud.)

These animals have a range of behaviors, with different individuals specializing in different techniques. “One dolphin does this, another does that,” she says.

“This helps reduce competition between individuals, and gives the [fish-kickers] an advantage over those doing the same thing as everybody else.”

Safe distance

Before thinking about using a drone, it’s important to know the limitations and risks involved with filming wildlife.

McCarthy told National Geographic that he’s careful not to harass the dolphins by getting too close with his Mavic 2 drone, which he said he specifically chose because it’s designed to be relatively quiet. To film these videos, he maneuvered the drone about 500 to 600 feet away from the animals at a height of 100 feet or more and zoomed in using the GoPro, he says.

If the drone is close enough to be noticeable, “you ruin the opportunity and you annoy the dolphin, and that’s never good,” he says. (Learn more: Here’s how to photograph wildlife ethically.)

Harassing these and other aquatic animals is also against the law, a violation of the Marine Mammal Protection Act, which can result in fines or worse. When viewing dolphins or other animals from directly above, any type of “aircraft” is not supposed to go below a thousand feet, according to recommendations by the National Oceanic and Atmospheric Administration.

This specific altitude, however, comes from the aforementioned act, which was written in the early 1990s before drones were widely available. Meanwhile, according to the Federal Aviation Administration, drones cannot usually be flown higher than 400 feet so as to not interfere with helicopters and airplanes.

Thus, the use of drones to film wildlife falls into a bit of a legal gray area. Technically, researchers that use drones should apply for permits that allow them to briefly come closer than 400 feet.

Regardless, NOAA asks observers not to approach within 50 yards of animals in a boat, says Stacey Horstman, the agency’s bottlenose dolphin conservation coordinator.