Growing scientific evidence that some invertebrates can experience pain and suffering is reshaping welfare ethics and policy, extending concern beyond vertebrates to insects, crustaceans, and cephalopods.
Invertebrate welfare research is reshaping the boundaries of animal welfare concern. For decapod crustaceans, the evidence for pain experience is now sufficiently strong that the UK has extended legal protection and many welfare scientists recommend precautionary welfare standards. For insects, the evidence is more contested, but the sheer scale of insect populations in agriculture and the wild means that even small probabilities of sentience have enormous welfare implications. Cephalopods including octopuses and squid show remarkable cognitive complexity that suggests rich subjective experience. The precautionary principle - giving the benefit of the doubt to species where sentience is uncertain - is increasingly influential in welfare policy.