A robotic submersible has captured, for reportedly the first time ever, a great white shark sleeping.
Aired on the Discovery Channel's Shark Week 2016's Jaws of the Deep, the video allegedly captures "the first-ever footage of a great white shark napping".
Ian Tibbetts, a marine biologist at the Centre for Marine Science at the University of Queensland, said he couldn't tell whether the female shark is asleep or not.
"The shark is swimming into a current and opening its mouth. Great whites swim all the time to maintain buoyancy," Tibbetts told The Huffington Post Australia.
The video explains if the shark stopped swimming it would fall to the bottom of the ocean and could die as a result of restricted oxygen.
By swimming all the time a constant flow of water moves through the sharks gills keeping it alive.
Tibbetts said the shark seems to be in some sort of resting phase.
"When something eats other large things periodically, it's in its interest to conserve its energy. By reducing all muscle movement the shark extends the amount of time between meals," Tibbetts said.
And because sharks don't have eyelids like humans, Tibbetts said it makes it even harder to determine whether the shark is asleep.
"Sharks do have membranes that close over the eyes, but only when they're attacking prey."
To prove whether the shark is actually sleeping or not, Tibbetts said the shark's brainwaves would need to be examined.
"But it will be a little while before they do that to a great white," he said.