Non-human animals have served as valuable models in many types of biomedical investigations, but when it comes to pain, some assumptions are necessary. We can measure nociception at the neuronal level, but must infer that signs of agitation and avoidance in rats or frogs mirror human behaviors – that is, that they feel what we call pain.
Morphine blocks the ability of goldfish to learn to avoid an electric shock, and fish given noxious stimuli sometimes engage in a rocking behavior.1Is that a response to pain? James D. Rose, professor of zoology and physiology at the University of Wyoming and a visible participant in the "Do fish feel pain?" debate, says they do not.2 "Neurologically, so much distinguishes fish and us. For example, fish get caught twice in rapid succession all the time, and they eat sea urchins and other spiny things. So, their reaction to noxious...