The squid creature wanders in the basin of water, its fins ripple and its eyes shine, and when scientists cast shrimp in the basin, this moll creature, cousin of octopus and squid (Calamari / Arrow of the Sea) prepares and releases its weapons like a frog towards the bait to pick it up.
But there is an unusual piece of information missing from the previous paragraph, which is that this small-sized vertebrate was wearing 3D glasses.
Putting 3D glasses on the squid was never an easy task in the service of science.
"Some people won't wear it whatever you try," says Trevor Wardell, University of Minnesota Sensory Neurologist. But together with his other colleagues, he managed to lift the squid out of the water pool, and gently put a glue between his eyes and then used velcro (a strap of two pieces of cloth that stick together) to fix the three-dimensional glasses with blue and red lenses over his eyes.
This whimsical eyeglasses were part of an effort to find out if the cuttlefish saw things stereoscopic, using the distance between their eyes to generate a sense of depth like humans.
The team's findings - published Wednesday in the "Science Advances" magazine - indicate that contrary to what scientists had thought in the past, squids can really see stereoscopic objects.
How do you confirm that?
Scientists say: Although octopus and squid are accomplished hunters, they do not seem to have the advantage of 3D vision like ours. But squid eyes often focus in harmony when they fish, and there is great overlap in what each eye sees, and this is a promising mixture to generate a 3D vision.
So Dr. decided. Rachel Fjord, a graduate student at Cambridge University, and his team, experimented with 3D glasses during a visit to the Marine Biology Laboratory in Woods Hall, Massachusetts.
The glasses cover each squid's eyes with a different color lens (one blue and the other red) to give it a vision of two different colors for any scene, with a slight displacement from each other in a manner that is supposed to lead to the formation of a three-dimensional image.
By playing a video on the basin wall of silhouettes of a pair of shrimp, each with a different color separated from each other at different distances, researchers can make the (imaginary) shrimp look closer or farther to the squid, and if that works, the squid will have tested the 3D vision .
To test this hypothesis, the team left the squid hungry, then placed it in the basin, one of whose walls represents the video screen, and they noticed that the squid began spying on the "shrimp" before retreating a little and then launched its tentacles to catch the mirage.
And this backward movement meant a lot to the researchers, because the squid uses its sensors to hunt its prey from a certain distance, and it relies on toothed suckers at the front of those sensors to pick up and pull the meal before chewing it, so if it is close or far excessively, then the front of these sensors will not touch the prey in the form Required.
The researchers also tried to project other fake images of shrimp to make it appear further away, so the squid would approach it.
All these experiments proved to the researchers beyond a reasonable doubt that the cuttlefish can see their prey in stereoscopic form, and in the intestine it has also been proven that it can watch 3D movies using stereoscopic glasses like humans too.