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Environmental Enrichment For Nonhuman Primates Resource Guide: Introduction

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In 1985, the Animal Welfare Act (AWA) was amended to include, among other things, providing for the psychological well-being of nonhuman primates. In time this concept became synonymous with the terms "environmental enrichment" or "environmental enhancement." The Congressional delegates responsible for the new amendments intended to allow for more exercise, play, and compatible social interactions for captive nonhuman primates. In 1989, the United States Department of Agriculture (USDA), Animal and Plant Health Inspection Service (APHIS) responded to the new AWA amendments by drafting regulations based on the advice received from a group of 10 primate experts.

These proposed regulations contained requirements for social housing, inanimate enrichment items, and exercise for nonhuman primates. APHIS eventually amended the regulations with more general language after receiving public comments on the proposed standards. The regulations became a final rule in 1991 and still exist today (9 CFR Sec. 3.81). (For more information on the history and intent of the 1985 amendments, see Kulpa-Eddy et al., 2005.)

After five years of enforcing the regulations on environmental enrichment for nonhuman primates, APHIS surveyed their Animal Care (AC) inspectors about the implementation of enrichment plans at research facilities, exhibitors, and dealers. The consensus among AC inspectors was that most facilities did not understand how to develop an adequate environmental enrichment plan that would promote the well-being of nonhuman primates. In response to this concern, additional clarification was set forth in the Final Report on Environment Enhancement to Promote the Psychological Well-being of Nonhuman Primates which was included in a draft policy and issued for public comment on July 15, 1999. Ultimately, the policy was not implemented. However, the draft policy and Final Report did provide a great deal of science-based information for facilities housing nonhuman primates and many began implementing aspects identified under five general elements (social grouping, social needs of infants, structure and substrate, foraging opportunities, and manipulanda).  Both the draft policy from the Federal Register and the Final Report on Environment Enhancement to Promote the Psychological Well-being of Nonhuman Primates are included in this information resource.

Environmental enrichment is defined by the Library of Congress as "enhancing the environment of confined animals in order to encourage natural behaviors and improve their quality of life (Kreger, 1999). An effective environmental enrichment program enhances species-appropriate behaviors and activities, increases behavioral choices, and encourages appropriate responses to environmental challenges. Environmental enrichment for nonhuman primates can include provision of novel objects, increased foraging opportunities, and opportunities for social interaction. After the 1985 AWA amendments, many facilities initially approached environmental enrichment as simply giving the animals toys. However, in response to published research and input from specialists, including the writers of the USDA draft policy, many facilities housing nonhuman primates now regard their enrichment plans as part of a larger behavioral health and management program. Weed and O’Neill-Wagner (2006) discuss the evolution of behavioral management programs in zoos and laboratory research environments starting on page vii of this document. The creation of a successful behavioral management program and subsequent environmental enrichment plan is based on an understanding of the natural history of each particular species. Facilities that maintain nonhuman primates in captivity develop enrichment plans by taking into account species-appropriate behavior, individual animals’ medical and behavioral histories, and the current limitations of the setting. The safety of the animals and personnel should always be considered.

In the United States, USDA, APHIS, AC is responsible for enforcement of the AWA. AC implements the standards for humane care set forth in the AWA and regulations and achieves compliance through inspections of regulated facilities, educational programming, and cooperative efforts with other agencies and organizations. For laboratory animal care, the National Institutes of Health (NIH), Office of Laboratory Animal Welfare (OLAW) enforces the Public Health Service (PHS) policy on Humane Care and Use of Laboratory Animals for researchers receiving federal funding from PHS. The contact information for both agencies is provided here.


Kreger, M. (1999). Environmental Enrichment for Nonhuman Primates Resource Guide. Animal Welfare Information Center Beltsville, Maryland, USA, 115 p.

Kulpa-Eddy, J.A., S. Taylor, and K. Adams (2005). USDA Perspective on Environmental Enrichment for Animals. ILAR Journal 46(2): 83-94.