A scientist and a seafood chef walk into a bar. “We have a mutual interest,” says the scientist. “I study crustaceans and you cook them. ” But the chef wanted to know just one thing: Do the animals feel pain?.
Rick Stein asked Robert Elwood this question in a pub on the coast of Northern Ireland. Elwood had been working with crabs and prawns for about thirty years. Elwood was stumped. “It was the first time I ever considered the question,” he says.
It scares some people to think about cooking lobsters while they are still alive or ripping crab claws off of live crabs before throwing them back into the water. But those opinions are just guesses. We know very little about whether these animals — or invertebrates in general — actually suffer. In Elwood’s experience, researchers are either certain the animals feel pain or certain they don’t. “Very few people say we need to know,” he says. Advertisement.
The global food industry farms or catches billions of invertebrates every year. But unlike their vertebrate cousins, they have virtually no legal protection. As a young lawyer, Antoine Goetschel learned early on that when the law talks about animals, it doesn’t mean insects. Goetschel is an international animal law and ethics consultant based in Zurich. “As long as the common opinion is that invertebrates do not suffer, they are out of the game. ”.
Pain is an awkward thing to test. It can’t be measured directly or pointed at; it’s not even easy to define. How do we know when an animal is in pain? A lot has changed since Descartes said that all animals other than humans were just automata that didn’t have any feelings or self-awareness. But much of what we think we know still involves a lot of guesswork.
How can we answer Stein’s question? Elwood has been thinking about this since he met Stein eight years ago. For a start, arguments by analogy are silly, he says. It would be like saying crabs can’t see because they don’t have a visual cortex if you don’t believe they feel pain. ”Advertisement.
Instead, Elwood and his colleagues at Queen’s University Belfast are looking at how these animals act to answer the question. Most organisms can respond to a stimulus that signals a potentially harmful event. Nociceptors are special receptors that are found in all animals, from humans to fruit flies. They can sense things like high temperatures, smelly chemicals, or mechanical injuries like being crushed or torn. A parasitic wasp may poke an egg-laying ovipositor into a fruit fly larva. The larva feels the needle and curls up, which can make the wasp pull out.
When an animal reacts to something we would think is painful, however, that doesn’t always mean the animal is in pain. It’s possible that the response is just a reflex, in which case signals don’t go all the way to the brain and go around the parts of the nervous system that are responsible for feeling pain consciously. When we scald our hand, for example, we immediately — and involuntarily — pull it away. Pain is the conscious experience that follows, once the signals have reached the brain. Elwood had to look for responses that went beyond reflexes, like how crustaceans limp or take care of a wound.
He started with prawns. He thought he knew what to expect because he had worked with them for so long: he would only see reflex reactions. To his surprise, when he rubbed acetic acid on their antennae, they started grooming the treated antennae by moving both front legs in long, complicated ways. Whats more, the grooming diminished when local anesthetic was applied beforehand. Advertisement.
He then turned to crabs. If he gave one part of a hermit crab a short electric shock, it would rub that spot with its claws for long periods of time. Brown crabs rubbed and picked at their wound when a claw was removed, as it is in fisheries. At times the prawns and crabs would contort their limbs into awkward positions to reach the injury. “These are not just reflexes,” Elwood says. “This is prolonged and complicated behavior, which clearly involves the central nervous system. ”.
He investigated further by placing shore crabs in a brightly lit tank with two shelters. During the day, shore crabs like to hide under rocks, so they should find a place to stay and stay there. But giving some of the crabs a shock inside one of the shelters forced them to venture outside. The crabs that had been shocked were much more likely to change their minds about where to live after just two tries. “So there is quick learning,” Elwood says. “That’s what you would expect from an animal that has been hurt.” ”.
Finally, Elwood looked at how the need to escape pain competed with other desires. For humans, pain is a powerful motivational driver, and we go to great lengths to avoid it. But we also can override our instincts and choose to endure it if the rewards are great enough. We suffer the dentist’s drill for the long-term benefit, for example. What would a crustacean want badly enough to make it endure pain?Advertisement.
For hermit crabs, it turns out to be a good home. Even though these animals live in empty seashells, you can get them to leave if you shock them inside the shell. Elwood found that a hermit crab’s decision to throw away its shell after being shocked depends on both how strong the shock is and how desirable the shell is. Crabs in better shells took bigger shocks before they were willing to move out. This suggests that the crabs are able to weigh different needs when responding to the noxious stimulus. Once again, this behavior goes far beyond reflex, Elwood says.
And it is not just crustaceans. Robyn Crook is an evolutionary neurobiologist at the University of Texas Health Science Center in Houston. She asks a lot of the same questions about octopuses and squids. “We are learning things we never expected to find,” she says. Advertisement.
Crook and his colleagues have only recently shown that cephalopods have nociceptors at all. She has also found that octopuses behave in a lot of the same ways vertebrates do when they are in pain, like grooming and protecting an injured body part. If you touch them near a wound, they are more likely to swim away and squirt ink than if you touch them somewhere else on their body.
Squids, though, may feel pain very differently. Nociceptors start to work not only where the squid’s fin was hurt, but also all over its body, all the way to the other fin, soon after the fin was crushed. This means that if a squid is hurt, it might not be able to pinpoint where the pain is coming from; instead, it might feel it all over.
Crook is not certain why this would be. But it makes sense from a squid’s point of view, she says. A squid’s tentacles can’t reach as many parts of its body as an octopus’s can, so it couldn’t treat a wound even if it knew where it was. Squids also have a fast metabolism that forces them to stay on the move and keep hunting. An all-over heightened sensitivity may keep a squid generally more alert and wary. Crook has found, for instance, that a squid that has been hurt will be more sensitive to touch and sight than others. “Its long-term behavior changes,” she says. “This fulfils one important criterion for pain. ”.
The question of whether abalone a type of sea snail can feel pain is an interesting one. As shellfish, abalones have very simple nervous systems compared to mammals and lack certain brain structures that are associated with conscious experience in more complex animals. However, recent research indicates they may be capable of more sentience and awareness than previously thought. This article will examine the evidence around abalone sentience and their capacity to feel pain or distress.
What are Abalones?
Abalones are a family of medium-sized edible sea snails that have been popular as a food source for humans across the world. They have oval-shaped shells with a row of holes along the outer edge. Abalones live on rocky surfaces near the shoreline and feed on seaweed using their radula, a tongue-like strip covered in tiny teeth that scrapes algae off rocks.
There are around 100 species of abalone worldwide found mostly in cooler waters along the west coast of North and South America, South Africa, Australia, and New Zealand. Commercial abalone fisheries exist but wild populations have declined due to overfishing. Some species are now being farmed.
Abalone Nervous System and Brain
Like other mollusks, abalones have a decentralized nervous system without a brain. Instead of one centralized brain controlling everything, they have clusters of nerve cells called ganglia that are distributed throughout their body. The ganglia connect to form a simple nerve network that coordinates movement and responses.
Abalones completely lack higher processing areas or an actual brain. They have no cerebellum for motor control no amygdala for emotions like fear and no neocortex for sensory perception and cognition. This suggests a very basic awareness of their surroundings and reflexive responses rather than advanced cognition or feeling.
Their rudimentary nervous system implies a limited capacity to process pain or nociception on anything beyond an unconscious reflex level. However, recent research indicates there may be more going on than previously thought.
Evidence Abalones May Feel Pain
While abalones lack a brain capable of conscious pain experience, there are a few lines of evidence indicating the potential for some form of sentience:
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Respond to tissue damage – Abalones react to potential tissue damage from predator attacks by withdrawing their soft body deep into their shell. This may demonstrate nociception or a reflexive response to harm.
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Stress behaviors – Stressed abalones exhibit behavioral changes consistent with pain in more complex animals. This includes reduced feeding, avoidance behaviors, and abnormal posturing.
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Analgesic effects – Human analgesics like morphine appear to have a calming effect on stressed abalones, implying they may feel pain that is relieved by pain-blocking drugs.
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Opioid receptors – Abalones have been found to have opioid receptors in their nervous system. Opioids play a key role in both modulating pain and producing pleasure/positive feelings in many animals. The presence of these receptors implies abalones may experience pain-like states.
So while abalones may not have the neural complexity for conscious pain awareness, they appear capable of more than just nociceptive reflexes. Some type of primal sentience involving aversive states that abalones strive to avoid or relieve may exist.
Potential Explanations for Abalone Sentience
If abalones do have some degree of sentience and capacity to feel pain or distress, how is this possible with such a simple nervous system? A few hypotheses exist:
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Distributed processing – Abalone ganglia may collectively process information much like the compartments of a brain working together. Their ganglia network may support primordial feelings and motivations.
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Novel structures – Abalones could have unique nerve structures and neurotransmitters that produce sentience through different mechanisms than in mammals and other animals.
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Invertebrate awareness – Our understanding of invertebrate cognition is limited. Advanced capacities for memory, learning, and even consciousness may exist in some invertebrates despite their lack of a vertebrate brain.
Overall, abalones likely have greater neurological capabilities than their basic ganglia would suggest. More research is needed to understand the mechanisms behind their potential sentience.
Do Abalones Feel Pain Like Humans?
It’s unlikely abalones experience pain in the same complex way humans do. Some key differences:
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No brain structures for advanced processing – Abalones lack areas like the neocortex and amygdala that produce our rich conscious experience of pain that is intertwined with emotion.
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Limited pain behaviors – Reactions are mostly reflexive. Complex pain behaviors driven by higher cognition are not observed.
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Different neurochemistry – Mammalian brains use extensive endorphin, serotonin and dopamine signaling related to pain perception. Abalone neurochemistry is still largely unknown.
So abalone sentience probably does not equate to human-like suffering. However, a basic capacity for primal feelings of discomfort, stress or harm that abalones avoid or seek to ameliorate appears plausible based on current evidence.
Practical Implications of Abalone Sentience
If abalones are confirmed to have some degree of sentience and the ability to feel pain or distress, this could influence how they are treated in fishing, aquaculture, and research:
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Minimizing stress and injury during wild harvests and on farms.
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Using analgesics or anesthetics prior to procedures that cause harm.
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Optimizing water quality and conditions to avoid environmental stress.
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Considering regulations around abalone welfare in commercial operations.
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Rethinking the scope of animal sentience to include invertebrate species.
While our understanding of abalone sentience is still evolving, precautions to avoid suffering seem warranted based on their importance as a food source and the latest scientific evidence.
The question of whether primitive invertebrates like abalones can truly feel pain in any capacity remains controversial. Their basic nervous system and lack of higher processing structures suggest a limited ability for sentience. However, stress behaviors, opioid receptors, and reactions to analgesics paint a more complex picture of abalone inner experience. While not experiencing human-like suffering, emerging evidence implies abalones may feel some primal form of discomfort, stress or harm that they actively avoid. This opens up discussions around how we ethically treat and study sentient invertebrate species, even those very alien from us biologically. As neuroscience progresses, we may continue finding sentience and inner experience manifesting through surprising neural mechanisms very different than our own.
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If not the backbone . . .
Despite this work, the topic remains controversial. One concern is where to redraw the line if the backbone no longer marks a boundary. After all, roughly 98 percent of all animal species are invertebrates; Elwood and Crook may be only scratching the surface. The differences between octopus and squid show how diverse the experiences of the rest of the invertebrates might be, Crook says. A crustaceans neurons number in the low hundreds of thousands. If they feel pain, she says, what about fruit flies? They have a similar-size nervous system.Advertisement
Fruit flies are known to have nociceptors, and it is likely that other insects do, too. Bees also respond differently to electric shocks given with and without anesthetic. And insects, generally, seem capable of learning to avoid noxious stimuli. But can they suffer?.
Hans Smid, who studies the brains and learning behavior of parasitic wasps at Wageningen University in the Netherlands, dismisses the possibility. “I am absolutely convinced that insects do not feel pain,” he says.
Like Elwood’s, Smid’s interest in pain began with a simple question. A reporter who came to visit a few years ago was shocked at how easily Smid caught a wasp that had gotten out of its cage. Why hurt an animal you are so enthusiastic about, the journalist wanted to know.
But Smid is sure that the best way to understand how insects act is through a fairly simple set of reflexes and innate responses. Unlike crustaceans, insects seem to have no pain-related behaviors. If an insect hurts a leg, for example, it doesn’t clean or try to protect the limb afterward. Even in extreme cases, insects show no evidence of pain. Imagine a praying mantis eating a locust, Smid says. With its abdomen opened up, the locust will still feed even while being eaten.
Why Is Abalone Called A Sea Snail? – Abalone Dissection
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