Crabs Can Feel Pain, Researchers Confirm

Whether or not crabs can feel pain has been a topic of debate for decades now – specifically because crustaceans lack areas of the brain associated with human pain sensation. But after administering electrical shocks, researchers confirmed elevated stress hormones and aggravated behaviors, indicating crustaceans do sense pain – probably including when they are plunged into scorching water, researchers report.

To get a better sense of their ability to sense pain, researchers from Queen's University examined 40 European shore crabs (Carcinus maenas) that are native to the Atlantic coast of Europe and northern Africa, inhabiting rocky shores, cobble beaches and tidal marshes. The crabs were placed in individual tanks where they received 200-millisecond electrical shocks every 10 seconds for two minutes. Changes in behavior – in any way – along with physiological changes, such as elevated stress hormones, meant the crabs were responding to pain, say researchers  

In response to their repeated electrical shocks, researchers found 16 of the crabs displayed aggravated behavior – circling the tank or trying to climb out – compared to the crab control group that remained motionless or simply walked around casually. The shocked crabs also exhibited elevated levels of lactic acid, a clear sign of stress, researchers reported.

The recent study was published in the journal Biology Letters. 

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