Scientists have proven that crabs and other crustaceans do feel pain even though they have no spinal column or backbone, and are able to recall an unpleasant experience and take action to avoid it happening again. The study by researchers at Queens University in Belfast suggests that when shore crabs (which is a close relative to the species we use for food) are given small electric shocks while hiding in dark shelters, they try to escape being zapped again by opting to migrate to another hideout. Previous research has shown that prawns and hermit crabs also react to painful situations. They say they now believe that all decapoda crustaceans (a group that also includes lobsters and crayfish) would show the same response. The finding could have important implications for the food industry, where many chefs boil crabs, lobsters and prawns alive in the belief that they are impervious to pain. Worse still, many seafood suppliers simply rip off the legs or abdomens of live animals to keep for sale, while throwing the less valuable parts back into the sea. There were currently no regulations to protect the welfare of these animals.
WHAT ARE INVERTEBRATES?
Invertebrates are classically defined as animals which lack a backbone or dorsal nerve cord, such as insects, crustacean (shrimp, lobster and crab), and molluscs (clams, snails, and squid).
Honeybees deserve special care because they display social behaviour and a capacity to learn and cooperate. Invertebrates do not feel pain because they have basic nervous systems and small brains. Crabs and lobsters have only about 100,000 neurons, compared with 100bn in people and other vertebrates. While this allows them to react to threatening stimuli (simple reflex). Tiny perforations in leg bones allow crabs and lobsters to jettison limbs if trapped by predators.
PAIN vs SIMPLE REFLEX
Pain is defined by the International Association for the Study of Pain (IASP) as “An unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.” The only animals capable of feeling pain are those that can feel fear, anxiety, distress and terror, similar to what humans feel when we receive “noxious stimuli”. Almost all organisms, including bacteria, will attempt to escape from it. Because they can detect harmful stimuli and withdraw from the source of the stimuli but that could be a simple reflex without the inner feeling of unpleasantness that we associate with pain. Possessing an escape response is not enough evidence to demonstrate that a species is capable of feeling pain.
DO FISH FEEL PAIN?
It is a question that has puzzled scientists and anglers for generations, but now a team of researchers at the Norwegian School of Veterinary Science and Purdue University claims to have demonstrated that fish do feel pain. The creatures can clearly be seen to react to a jab or blow and it was not a simple reflex. The findings are reported in the journal “Applied Animal Behaviour Science.” In a study carried out at the Roslin Institute, near Edinburgh in 2003, rainbow trout which had their lips injected with acid or bee venom were observed to rub the affected area on the gravel at the bottom of their tank, leading the researchers to conclude that they were in pain. The fish were found to have 58 nerve receptors on their faces and heads. Each year millions of fish are caught on barbed hooks or left to die by suffocation on the decks of fishing boats.
by:Let’s Explore & Learn