Research into invertebrate sentience is advancing rapidly, challenging assumptions about which animals deserve welfare consideration.
The precautionary principle suggests we should extend welfare consideration to animals with neurological complexity sufficient for sentience, even where certainty is lacking. The invertebrate welfare frontier matters enormously because the numbers are staggering — billions of insects, crustaceans, and cephalopods are affected by human industries. Small per-animal improvements scale to enormous total welfare impact.