Cuttlefish were shown 3-D clips of shrimps in a bid to test their eye-sight.
Scientists have long been puzzled with the prey-hunting ability of cuttlefish. The molluscs have the ability to scope out a 360-degree field of vision as its eyes move independently.
Scientists at the University of Minnesota set up an experiment to test whether cuttlefish could judge distance or depth like humans do.
The perception of depth is called binocular vision or stereopsis.
Dr. Trevor Wardill, who led the work at the Marine Biological Laboratory in Woods Hole, Massachusetts, said in order to test if the cuttlefish used stereopsis, the “cuttles” were made to wear 3-D glasses and watch 3-D shrimp movies, The Guardian reported.
Many told Wardill and his team that the molluscs would “rip the glasses off”.
Although making the glasses stick on the cuttlefish was difficult at first, but it worked after superglued velcro strip was added to the glasses.
The experiment was carried on cuttlefish called Supersandy, Long Arms, Inky and Sylvester Stallone.
They were placed in an underwater tank that had a movie screen attached to it. The scientists played moving images of shrimps, the favourite snack of cuttlefish, on the screen.
A high-speed video camera was set up which recorded their movements.
When a human being watches a 3-D movie, each eye sees the visual moving in a slightly different position. The brain then combines the images into one and uses triangulation to figure out how close objects are.
The same method was used in this case.
According to The Guardian, the scientists noticed that if the images were placed a long way apart, the cuttlefish thought the shrimp was really close and backed up to shoot their tentacles at their prey.
But if the images were flipped around, the shrimp seemed to be behind the screen. In this case, the cuttlefish would “swim right into it,” said Wardill.
The study was published in Science Advances and concluded that cuttlefish did use stereopsis but used different neural circuitry to do so.