Enrichment is an animal husbandry practice that enhances animal care by identifying and providing the stimuli necessary for well-being. The goal of enrichment is to improve an animal's physical and psychological health by increasing species-specific behaviors and decreasing abnormal behaviors. The purpose of behavioral enrichment is to improve the overall welfare of animals in captivity and create a habitat similar to their wild environment.
For each animal in captivity, a goal-oriented plan should be outlined and created to meet the needs of that animal specifically. Many different factors are included in making an enrichment outline including the needs of the species, their desired behaviors, an individual history, and the animal's current habitat. This plan is then put into action and changed based on the response and changing needs of the animal.
A variety of enrichment techniques are used to create desired outcomes similar to an animals individual and species' history. Each of the techniques used are intended to stimulate the animal's senses similarly to how they would be activated in the wild. Provided enrichment may be seen in the form of social, auditory, olfactory, visual, environmental, feeding, and training. Enrichment can be offered to any animal in captivity.
In the United States, specific regulations must be followed for enrichment plans in order to guarantee, regulate, and provide appropriate living environments and stimulation for animals in captivity. Primates, especially, have strict laws outlined by the USDA : https://www.nal.usda.gov/awic/environmental-enrichment-nonhuman-primates-resource-guide-us-laws-regulations-and-guidelines