Crabs are usually cooked alive before eating. The fact is that crabs do not feel pain because they lack the areas of the brain responsible for processing pain.
But is it so – or can crabs suffer?
shore crabs (Carcinus maenas) can, according to an October study in the journal Biology. Researchers have found that these crabs have nociceptors, nerves that detect physical damage and send a pain signal to the brain.
The researchers tested the responses of 20 crabs to painful things, such as pokes from a plastic tool or a small amount of vinegar applied to their eyes, horns and soft tissue between the claws and joints. The electrodes measured their central nervous system responses, and the scientists saw that they corresponded to nociceptive responses. This was not the case when the researchers used harmless substances such as sea water.
Nociceptors, which humans and many other mammals also have, are used when the body is injured or threatened. They communicate with the brain, through pain, that the body is facing a possible threat, so the animal can respond appropriately.
The mere presence of nociceptors does not mean the animal is in pain, said the study’s co-author. Eleftherios Kasiourasa biologist at the University of Gothenburg in Sweden. Nociceptors can cause pain – such as the natural removal of a hand from a hot stove. But people feel pain in our brains. So while nociceptors alone do not indicate that crabs feel pain, they are one piece of the puzzle.
Another study suggests the power of crabs to feel pain
Kasiouras told Live Science that he was not surprised to find pain receptors in crabs: Previous research has found lobsters and crabs respond behaviorally to pain. The combination of these behavioral responses and the response of the central nervous system makes it easier for the animal to feel pain.
Another way scientists measure an animal’s pain is with a list of values which includes whether the animal has nociceptors, brain areas associated with pain, interconnections between these receptors and brain areas, responses to anesthetics and defensive behavior due to injury or threat dangerous.
Research on hermit crabs shows that these animals have ways to protect themselves from danger. Hermit crabs will discard their shells to avoid being electrocuted, according to a 2016 study published in the journal. Ethical Practices. They are less likely to do so if there is a scent of a predator, suggesting that there is a careful trade-off between avoiding pain and avoiding predators. This adds weight to the idea that hermit crabs are in pain (rather than fleeing their shells as a reaction).
A new study on beach crabs makes another point, strongly suggesting that crabs can suffer.
Evidence has been given, scientists working in this field are to call restrictions boiling crabs and crabs while they are still alive, he said is an inhumane practice. There was a ban discussed and presented in the UK., but restrictions are already in place in Switzerland, Norway and New Zealand.
Scientists also looked at whether squids, clams and mussels met the criteria for suffering, but the results are different: They have nociceptors, and some show pain avoidance behavior, but scientists have not yet understood their brains as well as those of mammals.
“We humans use animals for food, laboratory research, and many other products,” Kasiouras said. “If they are suffering … we need to create a law on how to treat them humanely throughout their lives without suffering and to reduce their pain.”
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