North American freshwater mussels are among the most endangered animals on Earth; their welfare and sentience raise novel ethical questions.
While freshwater mussels have very simple nervous systems and the evidence for conscious experience is weak, their conservation crisis deserves attention. They are also harvested for shell buttons and the cultured pearl industry, involving collection and killing at scale. The uncertainty about their sentience, combined with their ecological importance and conservation status, suggests a precautionary approach to both their welfare and their habitat.