Scientific understanding of animal sentience has expanded dramatically, with evidence for consciousness, emotion, and suffering in a far wider range of species than previously recognized.
The expanding scientific consensus on animal sentience has profound welfare implications. If shrimp, fish, insects, and cephalopods experience suffering, the scale of animal welfare concern expands by orders of magnitude - these groups vastly outnumber mammals and birds in both wild populations and farmed systems. Welfare science advocates for applying the precautionary principle: when sentience evidence is uncertain but plausible, err toward protection rather than exploitation. This framework challenges industries that have operated on assumptions of non-sentience in animals that emerging evidence suggests are conscious.