Are invertebrates sentient?
Summary
Growing scientific evidence suggests that at least some invertebrates, particularly cephalopods (octopuses, squid, cuttlefish) and decapod crustaceans (crabs, lobsters, crayfish), are likely sentient. The UK became the first country to formally recognize these animals as sentient in law through the Animal Welfare (Sentience) Act 2022.
Evidence Summary
The question of invertebrate sentience has moved rapidly from the margins of scientific debate to the center of animal welfare policy. Invertebrates — animals without backbones — represent over 95% of all animal species, yet for most of scientific history they were assumed to lack the capacity for subjective experience. That assumption is now being challenged by rigorous evidence, particularly for cephalopod molluscs and decapod crustaceans.