Lobsters, crabs feel pain, scientists say

A common shore crab, used in new "pain" research, with wires attached to deliver a mild electrical shock. (Robert Elwood, Queen's University Belfast)

Shellfish such as crabs, lobsters and shrimp feel pain, suggests a new study that calls into question how food and aquaculture industries treat these animals.

Researchers have suspected for some time that live lobsters dunked into boiling water and rubber-banded crustaceans stored in crowded fish market tanks experience tremendous pain. Discovery News reported on that some years back. But it’s always a challenge for scientists to prove conclusively that a non-human is feeling pain.

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“On a philosophical point, it is impossible to demonstrate absolutely that an animal experiences pain,” researcher Bob Elwood of the Queen’s School of Biological Sciences, was quoted as saying in a press release. “However, various criteria have been suggested regarding what we would expect if pain were to be experienced. The research at Queen’s has tested those criteria and the data is consistent with the idea of pain. Thus, we conclude that there is a strong probability of pain and the need to consider the welfare of these animals.”

Elwood and colleague Barry Magee worked on the latest study, published in the Journal of Experimental Biology.

Elwood described how it went: “Ninety crabs were each introduced individually to a tank with two dark shelters. On selecting their shelter of choice, some of the crabs were exposed to an electric shock. After some rest time, each crab was returned to the tank. Most stuck with what they knew best, returning to the shelter they had chosen first time around, where those that had been shocked on first choice again experienced a shock. When introduced to the tank for the third time, however, the vast majority of shocked crabs now went to the alternative safe shelter. Those not shocked continued to use their preferred shelter.”

He continued, “Having experienced two rounds of shocks, the crabs learned to avoid the shelter where they received the shock. They were willing to give up their hideaway in order to avoid the source of their probable pain.”

While likely painful, the relatively mild electrical shocks did not otherwise harm the crabs.

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Crustaceans have a less extensive nervous system than humans do, which perhaps led some researchers to previously believe that shellfish do not feel pain. The reaction to typical pain-inducing stimuli is consistent with discomfort or worse, though, as the latest study found. If you’ve ever tried to boil a live lobster, you probably noticed that it did not just sit patiently in the pot. Most lobsters put up quite a struggle.

We often hear about concerns over the treatment of farm animals by animal advocates. For example, the American Humane Society has a Farm Animal Welfare certification program. Shellfish are often left out of such discussions, probably because they look, and appear to act, less like us.

Crabs, lobsters, shrimp and other crustaceans may experience the world more like us than we realize, though, with pain being a feeling that we all seem to share.