Global Overview of Environmental Enrichment Studies: What Has Been Done and Future Directions.

(1) Background: Environmental enrichment (EE) is a management principle aimed at meeting the needs of animals under human care by identifying and providing essential environmental stimuli to contribute to the integrity of their psychological and physiological well-being. Studies on EE have been carried out worldwide, but consolidated information on how it has been used, who it has been used for, how it has been evaluated, and what gaps still exist in the subject is scarce in the scientific literature. This study assessed, employing a systematic review, the global scenario of research into EE in animals kept under human care over the last 17 years, answering the above-mentioned questions.