The problems of quantifying pain in animals

: A classification of vertebrates concerning their pain sensibility from the anatomical or physiological point of view is made very difficult by the different pathways of nociception. The very good measurable stimuli are answered by a wide range of reactions. In search for approved parameters for the characterization of pain objectivity is often preferred to validity. Studies using animals in painful situations with and without analgetic treatment are considered favourable for pain evaluation. Each kind of evaluation of pain in animals has to take into account the different dimensions of pain perception. As a result we would like to follow Kitchell's statement (1980), as a guideline for the work with animals: "Overemphasis on the uncertainty of knowledge about pain in animals that leads to a denial that pain perception exists in animals is logically as well as empirically unfounded.