March 27, 2009 -- Ripping the legs off live crabs and crowding lobsters into seafood market tanks are just two of the many practices that may warrant reassessment, given two new studies that indicate crustaceans feel pain and stress. The findings add to a growing body of evidence that virtually all animals, including fish, shellfish and insects, can suffer. Robert Elwood, the lead author of both papers, explained to Discovery News that pain allows an individual to be "aware of the potential tissue damage" while experiencing "a huge negative emotion or motivation that it learns to avoid that situation in the future." Both pain and stress are therefore key survival mechanisms. Elwood, a professor in the School of Biological Sciences at The Queen's University in Belfast, and colleague Mirjam Appel studied hermit crabs collected from rock pools in County Down, Northern Ireland. All of the crabs survived the experiments and were later released back into their native habitat. Related Content:
Elwood and Appel gave small electric shocks to some of the crabs within their shells. When the researchers provided vacant shells, some crabs -- but only the ones that had been shocked -- left their old shells and entered the new ones, showing stress-related behaviors like grooming of the abdomen or rapping of the abdomen against the empty shell. Grooming, as for a person licking a burnt finger, "is a protective motor reaction and viewed as a sign of pain in vertebrates," the researchers wrote. It has been thought that the behavior of crustaceans is mostly reflexive, but the fact that they showed signs of physical distress at the same time they changed a behavior -- in this case, moving into another shell -- suggest they feel pain as well, according to the researchers. The research has been accepted for publication in the journal Animal Behavior. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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