Sentience in decapod crustaceans: a general framework and review of the evidence

Abstract

A framework for evaluating scientific evidence of sentience is outlined, focusing on pain experience. The framework includes eight criteria: nociception, sensory integration, integrated nociception, analgesia, motivational trade-offs, flexible self-protection, associative learning, and analgesia preference. Each criterion has confidence levels reflecting the reliability and quality of the evidence. The framework is applied to decapod crustaceans, a controversial candidate for sentience. True crabs (infraorder Brachyura) meet five criteria, providing strong evidence of sentience. Anomuran crabs (infraorder Anomura) and astacid lobsters/crayfish (infraorder Astacidea) meet three criteria, suggesting substantial evidence of sentience. The evidence is weaker for other infraorders, highlighting important research gaps. – AI-generated abstract