Animals are most often used for research in the areas of biological psychology and learning. General conditions and treatment of animals must be humane. Laws require that animals must be housed in clean, sanitary, and adequately sized structures. Discomfort from infection, illness, and pain must be kept at an absolute minimum at all times.

At left are Wistar lab rats, a strain of albino rats developed at the Wistar Institute in 1906. They are the most popular choice for laboratory research.