Research on invertebrate sentience has grown rapidly, with strong evidence for nociception and potential suffering in crustaceans, cephalopods, and some insects.
The question of invertebrate sentience sits at the frontier of consciousness science and animal welfare policy. Unlike vertebrate sentience - which is now broadly accepted - invertebrate sentience remains actively contested. However, the precautionary principle applies: given genuine uncertainty and the enormous numbers of invertebrates affected by human activities, extending consideration to likely sentient invertebrates is a prudent welfare policy. Legal recognition of crustacean and cephalopod sentience in several jurisdictions represents appropriate application of this principle.