Don’t be fooled by the big-mouthed basking shark’s sluggish demeanor, because it possesses one mighty trick. This mammoth fish, the second largest in the sea, can breach entirely out of the water at speeds comparable to those of great white sharks, according to a new study.

A team of international scientists used video analysis and a shark-mounted data logger to measure the vertical velocity of basking sharks as they tore through the water off the coast of Ireland. These typically slow, plankton-guzzling fish breached at approximately 5 meters per second, they report today in Biology Letters . That’s as fast as predatory great white sharks in South Africa, which clock in at 4.8 meters per second.

An accelerator mounted onto a male basking shark showed that in just 10 beats of its tail, the fish propelled itself from a depth of 28 meters to break the water’s surface in 9 seconds, accelerating at an astonishing speed of 5 meters per second.

This spectacle requires quite a bit of energy. In fact, scientists estimate that a single basking shark breach costs some 50% more, in terms of calories, than a comparable move by their similarly sized great white cousins. So, exactly why do they do it?

Great white sharks are notorious for their rapid breaches, which they use to hunt prey lingering near the ocean’s surface. But filter-feeding basking sharks wouldn’t need such a move to feed. It could be that they are ridding themselves of parasites, warding off predators, or perhaps even using their stunning acrobatics to attract mates. Regardless of the reason, researchers say these new data should shift our perspectives of other supposedly slow creatures—and shed a light onto the mysterious ways of the ocean’s gentle giants.