Standardization of enrichment

In laboratory animals, environmental enrichment was originally used as an experimental tool in neurobehavioral research as early as in the 1940s. At that time it was considered to be any modification of a captive animal‘s environment by providing physical or social stimuli. Environmental enrichment was also developed for zoo enclosures in response to the abnormal behaviours shown by animals in environments that did not meet their needs. Subsequent to the emergence of laboratory science as a scientific discipline of its own in the 1960ies environmental enrichment was introduced as a concept in laboratory animal care in the 1980s, i.e. with a delay of about two decades. The definition of environmental enrichment became more specific and included explicitly the well-being of animals as its major goal, e.g.: “Environmental enrichment is any modification in the environment of the captive animals that seeks to enhance its physical and psychological well-being by providing stimuli meeting the animals’ species-specific needs”. Even though enrichment was not a topic when Russel and Burch (1959) formulated their 3R-principles, it is obvious that the essence of enrichment in relation to animal welfare is refinement.