Changing the housing standard for monkeys in laboratories (2000)

Reinhardt, V., Roberts, A., Reinhardt, A.

Abstract

Permanent confinement in such extremely small, barren enclosures causes many individuals to develop the monotonous habits of stereotypically pacing back and forth, running in circles, somersaulting or bouncing up or down. ... The striking difference of illumination between upper and lower cage rows belies the scientific principle that environmental variables must be controlled strictly to ensure the validity of collected research data.The conventional solitary housing of laboratory monkeys in the traditional double-tier caging system is not only inhumane but it also undermines good scientific research methodology.