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Experiments reveal that crabs and lobsters feel pain

Cooked lobster

Lobsters and other crustaceans may feel pain.

Matthew Roy; Wikipedia

Every year thousands of them are boiled or torn apart while they are still alive, and   now there is strong evidence to suggest that crustaceans experience pain.

That was the stark message delivered by Robert Elwood, an animal behaviour researcher at Queen’s University Belfast, to the Behaviour 2013 meeting in Newcastle, UK, today.

Crustaceans — crabs, prawns, lobsters and other creatures — are generally not protected by animal-welfare laws, despite huge numbers of them being caught or farmed for human consumption. The exclusion has been based on the belief that these animals cannot experience pain — generally regarded as an ‘unpleasant feeling’ — and instead only have nociception, a reflex response to move away from a noxious stimulus.

This is a useful belief, as crustaceans are subjected to what Elwood calls “extreme procedures” — lobsters in factories having their legs removed while they are still alive, crabs being kept alive but tightly bound for days in fish markets, and live prawns being impaled on sticks for eating. Such procedures, he notes, “would never be allowed with vertebrates”.

One way Elwood attempted to determine whether crustaceans can experience pain was to look at avoidance learning: can the animals actually learn from pain, or do they just continue to respond to a stimulus? To answer this, Elwood and his colleague Barry Magee presented shore crabs with a choice of two different shelters. Entering one shelter resulted in an electric shock for the animal, which was repeated if the animal remained there. The other shelter was a safe haven.

Crabs shocked the second time the experiment was run were far more likely to choose the other shelter in the next trial, while crabs never left a non-shocking shelter. This, says Elwood, shows that the shock is aversive.

In another experiment Elwood investigated whether hermit crabs could make motivational trade-offs as a result of pain. They presented Pagurus bernhardus crabs with two types of shell, one of which the animals are known to prefer, and gave some of the animals small electric shocks when they were inside these new homes.

When these crabs were later presented with a new shell they could move into, the shocked crabs were more likely to take up this offer, and they did so more quickly.

“Assessing pain is difficult, even within humans,” Elwood told the Newcastle meeting. But there is a “clear, long-term motivational change [in these experiments] that is entirely consistent with the idea of pain”.

Such evidence would be enough to prevent mice being subjected to the deaths that crustaceans experience, he says.

Robert Hubrecht, deputy director of the Universities Federation for Animal Welfare (UFAW) and the organizer of the session at which Elwood gave his talk, says that the data for crustaceans appear equivalent to the kind of data that are used to give mice the benefit of the doubt, and thus award them protection from possible pain under the law.

“We’re behaving in an illogical way at the moment” by protecting mice but not crustaceans, he notes.

Whether wider society is ready to consider crabs as things that can feel pain and should be protected is not clear. “This is somewhere science has to lead,” says Hubrecht.

Comments

  1. Report this comment

    Mary Katharine OBrien said:

    DISCLAIMER: I don’t think I really understand sensory things or crustacean biology enough to really have a valid opinion on this, I’m just a 3rd year undergraduate in marine biology.

    While this is to be compelling evidence suggesting we treat crustaceans inhumanely, I’m skeptical of the analysis of these findings and have some questions about directly correlating the evidence of this experiment to pain from heat or physical injury. The experiment used electrical stimuli and not heat or physical injury, and so, while boiling them alive sounds very painful to humans, the argument seems to still be out on crustaceans response to temperature. I guess I am wondering if temperature and electrical stimuli lead to different responses in crustaceans or even in other beings. Also do crustaceans even have neurons/sensory organs in their carapaces or any part of their exoskeleton?

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    Charec Tiger said:

    So basically you’re saying that they are torturing those little helpless creatures to see their suffering? Nothing changed since 40’s.

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    Jean SmilingCoyote said:

    Just the calling of crabs “things” shows society has a very long way to go. In English, only inanimate entities should be called “things.” Crabs are living beings, and apparently sentient enough to be considered to feel pain. I suggest a simple rule: kill animals quickly after any live capture. Store them correctly as long as you like, as long as they’re dead, before cooking and eating.

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      Mary Finelli said:

      You are right, Jean, that animals should not be referred to as “things” (or “it,” or anything of the like).

      Since it has been shown that these animals are sentient, we should not cause them unnecessary harm. Since it is unnecessary to eat lobsters, or any other animals (see: http://tinyurl.com/csussh8 ), they should not be captured for food in the first place.

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    Dave Bialac said:

    The conclusions of this study are wrong for a couple of reasons:

    1) All that has been established is that these animals can perceive the sensation they’ve been introduced to. It doesn’t imply pain. If I was given a choice between two chairs: one where somebody constantly taped me on the shoulder and one where this didn’t occur, I’d pick the one where I wasn’t tapped. The study authors assume annoyance is perceived as pain.

    2) The Chirstmas Island Crab migration. As part of their migration, the Christmas Island Red Crab crosses over railroad tracks on the island. Many of the crabs will then park themselves under the tracks to “warm up”. Unfortunately, the tracks are very hot and end up cooking the crabs to death. If these crabs could perceive pain, they would flee. They don’t. They just sit under the tracks and cook.

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    Hindi Sahitya said:

    Any living organism may feel pain as I think. The same is being proved for crabs and lobsters also. This tell us to live in harmony with everyone living in the planet.
    Source: http://www.gharkavaidya.com

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