The squid are fast, sure hunters – the death on eight limbs and two waving tentacles for small creatures in their vicinity. They change according to the landscape and vary between different colors and even textures by using small structures that expand and contract under their skin. They even seem to have depth perception, and researchers use a small pair of 3D goggles that are found, and place them separately from octopuses and squid. And the accuracy of hitting prey is remarkable.
But for squid, these physical accomplishments in the pursuit of food are not the whole story. A new study published this month in the journal Royal Society Open Science shows that squid cognition is even more than scientists knew.
It seems that marine animals can do calculations that are more complicated than just ‘more food is better’. Offered with the choice between one or two shrimp, they will actually choose the single shrimp if they have learned from experience that they are rewarded for this choice.
While the brain-like nature of their octopus cousins gets a lot of attention, researchers studying animal cognition over the years have discovered surprising talents in squid. The cephalopods, for example, will hunt fewer crabs during the day if they learn that shrimp, their preferred food, are predictably available during the night. It shows that they can think ahead.
Chuan-Chin Chiao, a biologist at the national Tsing Hua University in Taiwan, and an author of the current article with his colleague Tzu-Hsin Kuo, has found in the past that squid that is hungry is a bigger harder to catch will choose. shrimp to attack, and those that are not, choose smaller, easier to catch.
But researchers have also found that animals do not always look logical at first glance. Like humans, whose behavior rarely matches the visions of economists who would do an ideal, rational being, animals respond to their environments using learned experiences.
In these new experiments, which were curious to see if they could change the value of squid to a single shrimp, the researchers gave the squid the option to go with one shrimp or a room with no one in a room. Each time they entered the room with a shrimp, the researchers gave them a smaller shrimp as a reward.
Then each squid took a second test. They were able to enter a room and chase two shrimp. Or they could enter another room that only had one.
“You would think that they always choose the larger quantity,” said dr. Chiao said. But that was not what happened.
In the second round, the squid chose one shrimp significantly more often than two. Squid that did not have the training chose two shrimp in one reliable way, which showed that those who chose the smaller number expected the reward and worked differently than their co-workers. Even waiting until an hour had passed since the initial training, the new behavior did not completely eradicate.
The process of being rewarded for choosing one shrimp apparently gave the option an extra glow as far as the squid is concerned, said dr. Chiao said. This suggests that they are not simply responding to basic trials they encounter – they remember what has come before and use it to make a choice. Although the behavior in this situation has not resulted in a greater distance, it contributes to the evidence that these are complex beings that can use their brains in ways that may surprise us.