For the first time, a great white shark has been caught napping on video by a team of scientists from the Pelagios Kakunjá and the Woods Hole Oceanographic Institution. The footage was aired by Discovery Channel on its Jaws of the Deep show as part of this year’s Shark Week event and posted on YouTube.

Thus far, very few species of shark have been observed sleeping, and their behavior still remains a mystery to experts around the globe. Discovery’s video could help solve this mystery once and for all.

The footage was taken by a robotic submersible. The video shows a female great white shark sleeping at night in the shallow waters of Guadalupe Island, located close to Mexico’s Baja California Peninsula.

Initially, the great white shark changed its behavior and swam to the bottom of the seabed. It swam slowly in a calm state while keeping its mouth open to let the oxygen-rich currents enter its gills with a tiny amount of effort.

The shark has to keep swimming because if it stopped, it would fall to the ocean floor and die due to lack of oxygen. Although scientists speculated that the swimming movement during sleep was regulated by a shark’s brain, a research claimed that it is directed by its spinal cord instead.

Ian Tibbetts, a marine biologist from the Center for Marine Science in the University of Queensland, doubts that this is a shark sleeping. Tibbetts told The Huffington Post Australia that the video may have simply shown the female shark in a resting phase.

“The shark is swimming into a current and opening its mouth,” Tibbetts points out. “Great whites swim all the time to maintain buoyancy.”

Large animals like sharks tend to conserve their energy by reducing their movements. They would be able to endure more time between eating when they reduce all their muscle movements.

Moreover, sharks do not have eyelids so their sleeping behavior is not that easily observable. These animals have membranes that close over the eyes that resemble eyelids but they only use it when attacking their next meal.

The only way to determine if a shark is really sleeping is by studying its brainwaves with a scanner. However, the marine biologist says it would take some time before anyone can do that.