The use of animals in research and instruction generally occurs in one of two contexts: the animals serve as model systems for the investigation of phenomena and processes which cannot be studied directly, or the animals are being studied to investigate a problem specific to the particular species. Most biomedical research falls into the first category. Examples of the latter include field studies of behavioral and ecological adaptations of animal species, studies of taxonomic relationships among species, or captive studies of physiological or behavioral processes which form an important part of the adaptations of one or more species.

This section reviews scientific, ethical, and humane considerations in experimental design and model selection for research involving animals.  Ethical and humane considerations should be viewed as compatible with good scientific practice. There is a body of literature that supports the premise that animals which are humanely cared for are healthier, both physically and psychologically, and therefore make better, more predictable, subjects. Similarly, unless a research project is intended to study pain itself, pain and suffering on the part of the animal subject will rarely, if ever, contribute anything positive to the experimental procedure. Thus, ethics and humane considerations can be viewed as integral parts of the process of experimental design and model selection.