Octopuses are the most cognitively sophisticated invertebrates, with their distributed nervous system, tool use, and apparent play behavior creating a strong case for welfare consideration.
Octopus intelligence presents one of the most compelling cases for extending welfare consideration beyond traditional boundaries. Their cognitive sophistication equals or exceeds that of many vertebrates despite having evolved intelligence independently from a common ancestor. Individual personality, tool use, problem-solving, and what appears to be play behavior indicate rich subjective experience. Their distributed nervous system with two-thirds of neurons in their arms means their pain and sensory experience may be more distributed and complex than vertebrate pain. The UK included cephalopods in its Animal Welfare (Sentience) Act 2022 based on this evidence. Welfare consideration for octopuses in research, aquaculture, and fisheries is now a legitimate scientific and policy question. The proposed farming of octopuses raises profound welfare concerns given this cognitive complexity.