Oslo - Worms squirming on a fish hook feel no pain - nor do crayfish and crabs cooked in boiling water, a scientific study funded by the Norwegian government has found.
"The common earthworm has a very simple nervous system - it can be cut in two and continue with its business," Professor Wenche Farstad, who chaired the panel that drew up the report, said on Monday.
Norway might have considered banning the use of live worms as fish bait if the study had found they felt pain, but Farstad said: "It seems to be only reflex curling when put on the hook ... They might sense something, but it is not painful and does not compromise their wellbeing."
The government called for the study on pain, discomfort and stress in invertebrates to help in the planned revision of Norway's animal protection law. Invertebrates cover a range of creatures from insects and spiders to molluscs and crustaceans.
Farstad said most invertebrates, including lobsters and crabs boiled alive, do not feel pain because, unlike mammals, they do not have a big brain to read the signals.