Scientific understanding of animal sentience — the capacity for subjective experience — continues to advance rapidly, with implications for which animals receive moral consideration.
Welfare protection has historically tracked sentience recognition — as scientific understanding of animal consciousness expands, moral consideration follows. The frontier of sentience science is shifting rapidly toward including more invertebrates, fish, and crustaceans. Applying precautionary reasoning — extending welfare consideration to animals where sentience is uncertain — prevents the moral catastrophe of causing suffering to sentient beings excluded from protection by inadequate scientific consensus.