Garden snails and slugs are among the most frequently killed animals in domestic settings through pesticides and physical methods. Their sentience is uncertain but growing evidence warrants more humane approaches.
Snail and slug welfare sits at the furthest uncertain frontier of welfare consideration: their sentience is genuinely unknown, their nervous systems are simple, and the welfare debate about them is primarily philosophical rather than empirical. Yet the precautionary principle, applied consistently, suggests that methods causing prolonged apparent suffering — metaldehyde poisoning, which causes hours of neurological distress before death — should be replaced with methods that cause faster death (ferric phosphate, which kills more quickly) or avoid killing entirely (physical relocation, predator encouragement). The welfare gain from snail-specific interventions is likely small given uncertain sentience; but the same interventions that benefit snails through reduced chemical use also benefit the many clearly sentient animals — hedgehogs, frogs, song thrushes — that eat snails and are harmed by pesticide exposure.