Florida International University marine scientist Yannis Papastamatiou and a team of researchers have found that hundreds of gray reef sharks are surfing the slope in the southern channel of Fakarava Atoll in French Polynesia by floating on the updrafts from currents. The team used acoustic tracking tags, animal-borne cameras and their own underwater observations to monitor the behaviour. They were able to calculate energy usage of those 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 is how they get oxygen), the surfing action gives them much-needed rest. The findings were published in Journal of Animal Ecology.