As it turns out, hammerhead sharks are as lazy as humans

Great hammerhead sharks swim like lazy human swimmers, choosing to roll on their side in order to conserve energy, a new study has found.

Researchers observing endangered great hammerhead sharks in Australia, Belize and Bahamas originally thought one of the predators was sick, but on closer observation found it would switch from one side to the other.

Further observations using underwater cameras and accelerometers led them to discover the predators spend up to 90 per cent of their time swimming rolled at angles between 50 and 70 degrees using their large dorsal fin to generate lift.

Hydrodynamic modeling with a physical model of a great hammerhead shark found the animal would suffer the least amount of drag, and therefore expend the least amount of energy, at precisely that angle range, Xinhua news agency reported.

"The animals reduce the cost of transport by about 10 per cent by using the side-swimming method" compared with traditional upright swimming, said researcher Adam Barnett from James Cook University in Australia.

"It just goes to show how much we don't know about what goes on in the ocean," said Barnett.

Great hammerhead sharks are solitary predators; however, due to overfishing and other human-related factors, they are disappearing from oceans at an alarming rate, the report said.

The research was published in the journal Nature Communications.