Surfing Is A Gray Reef Shark's Version Of A Power Nap, According To FIU Marine Scientist

MIAMI (CBSMiami) – What does a Gray reef shark do when it's tired of swimming? It goes surfing.

According to Florida International University marine scientist Yannis Papastamatiou, they're not seeking thrills, Gray reef sharks surf to conserve energy.

Papastamatiou and an international team of researchers found hundreds of gray reef sharks in the southern channel of Fakarava Atoll in French Polynesia are surfing the slope by floating on the updrafts from currents.

Papastamatiou noticed the odd behavior during a diving trip. He saw the sharks swimming against the current but were barely moving their tails. It looked like they were floating.

"During the day, they're pretty placid and relaxed, swimming with minimal effort," Papastamatiou said. "It's interesting because it's a pretty strong current."

Then something really caught his attention — the sharks had developed a conveyer-belt-like system. When one shark reached the end of the line, it allowed the current to carry it back to the beginning point. The next shark in line did the same. And then the next. Papastamatiou was intrigued.

So he launched a study, published in the Journal of Animal Ecology which used acoustic tracking tags, diver observations and even "animal-borne cameras" to observe the strange behavior.

Their work calculated energy usage of sharks that stayed in the channel surfing and those that left the channel. By hanging out and surfing the slope, the researchers say the sharks cut their energy by at least 15 percent. For an animal that can never stop swimming (since that's how they get oxygen), the surfing action gives them some much-needed rest.

Fakarava is a famous dive site and home to 500 gray reef sharks.

The findings could help explain why there are larger numbers of sharks in certain places and possibly help predict why sharks may prefer one area over another.