The total number of nonhuman primates in research in the US was 70,797 in 2018 (the most recent year for which figures are available), according to the US Department of Agriculture (USDA). This figure—does not include the 35,221 primates who were not assigned to research and who were instead part of laboratories' breeding colonies.
Primate species in research include rhesus macaques, crab-eating macaques, stump-tailed macaques, pig-tailed macaques, squirrel monkeys, owl monkeys, baboons, chimpanzees, marmosets and spider monkeys. Both wild-caught and purpose-bred animals are used, and in 2006 alone, 26,638 monkeys were imported into the US, according to the International Primate Protection League. Primates are subjects in studies involving toxicology, endocrinology, reproductive biology, neurology, behavior, cognition, genetics, and more, as well as the production of vaccines and medications for human diseases such as AIDS and hepatitis.
Historically, the basic needs of primates were ignored by those conducting research with them. The traditional method of housing primates in research was alone, in small barren cages. There was an unfounded concern that modifying the barren environment would introduce data-biasing variables and that the financial costs to accommodate the animals would be too great.
In 1985, the Improved Standards for Laboratory Animals Act (ISLAA) amendments to the Animal Welfare Act were passed, mandating among other requirements—“a physical environment adequate to promote the psychological well-being of primates.” The USDA, charged with enforcement of this requirement, however, was pressed by the biomedical research industry not to require that primates be housed in pairs or groups. Often, an unused toy was all one would find in the cages of primates, most of whom continued to be housed individually. A survey by Baker et al. in 2007, found that only 46% of the primates in research were housed socially.
Today, more than a quarter century after the legal mandate to provide for the social needs of primates, the USDA appears to be increasing its diligence, pressing laboratories to socially house their primates. Further, the new edition of the Guide for the Care and Use of Laboratory Animals (a manual research facilities are supposed to adhere to if they receive funds from the National Institutes of Health and/or they are accredited by the Association for Assessment and Accreditation of Laboratory Animal Care International) has undergone a dramatic philosophical shift in perspective that should benefit primates and other animals in research. The 2010 Guide calls for social housing and enriched cages, recognizing that providing these elements can reduce stress (itself a data-biasing variable) and lead to more reproducible results (better science) while improving animal welfare.
A humane ethic and improved scientific outcomes necessitate a look at the important behaviors of primates. They have a strong need for companionship, with grooming being a key social activity. In the wild, primates spend a major portion of the day foraging, and though primates in research laboratories have no real need to forage—a daily food ration is readily accessible—they are strongly motivated to work for their food. Climbing and perching are also important behavioral activities. The vertical dimension of the primate’s environment may be used for a variety of purposes, including foraging, rest and sleep, and to escape and feel safe from predators (in the laboratory, the humans are the predators).
AWI has been at the forefront of the push to improve conditions for primates in research. AWI worked towards the successful adoption of the ISLAA in 1985, provided data encouraging significant change in the new edition of the Guide, and has widely distributed extensive data on the needs of primates that by law and ethical obligation must be accommodated to the greatest extent possible in the research laboratory.
“Jack” is a cynomolgus macaque who was discarded at an animal control agency after suffering severe neglect. (On the voluntary surrender form the former owner stated “UNWANTED" as the reason for surrender.) Jack is now safe and recovering at OPR Coastal Primate Sanctuary in Longview, WA. One of his favorite activities is to play in the macaque pool, an excellent form of enrichment. Video courtesy of OPR Coastal Primate Sanctuary.