Scientists believe they may have discovered how great white sharks sleep.
How the creatures rested has previously been unknown, particularly as the species must be constantly on the move in order to breathe.
But using hi-tech robotics and underwater cameras, they now believe they know how the sharks – which can grow up to six metres long – take their slumber.
Footage, shot by the Discovery Channel, followed a female great white, nicknamed Emma, as the sun set near the Isla de Guadalupe, west of Mexico’s Baja peninsula.
As night fell, the shark’s behaviour began to change. While in daylight hours, great whites tend to stay in deep waters to swoop on prey, at night they are known to move in closer to the shore.
Emma is “hugging the shoreline, staying close to the bottom,” observes one of scientists in the film.
At 8.30pm, the researchers observed Emma’s jaws begin to open, and she entered “an almost catatonic state”. However, she continued to move through the water, albeit more slowly than usual.
If the shark was to stop moving, water would not flow through her gills and she would lose buoyancy, sink and suffocate.
In 2015, near the same Pacific island, biologist Mauricio Hoyos Padilla filmed what is thought to have been the largest great white ever recorded.
The 20 foot shark was believed to have been pregnant at the time.
