Primates & Science

AV magazine issue 3, 2011 2011 Issue #3 & 4 Primates & Science Why Monkeys Matter
Sue A. Leary

As an animal advocate, I have sat across the table from primate vivisectors and wondered, how can they do these things? How can they act so deliberately, taking an innocent being who looks at you with intelligent, expressive eyes, render him defenseless with drugs or physical restraint, and methodically cause suffering, and, eventually, death?

It's not just an anguished, idle thought. Understanding what factors drive the animal research enterprise leads to understanding what it will take to redirect it, and prevent the suffering of hundreds of thousands of non-human primates.

Recognizing that humans share so many qualities with our primate cousins, including the powerful bond between mothers and babies, and keen intelligence and adaptability, most people, including some researchers, have a higher level of concern about primates' ability to suffer. Consequently, the use of primates in experimentation is often challenged on ethical grounds.

In 2005, the Nuffield Council on Bioethics in the United Kingdom published an extensive report, "The Ethics of Research Involving Animals." Over a period of two years, members of a specially appointed committee reviewed available information and viewpoints on the welfare of animals used in laboratories. Trying to encompass all stages of an animal's life, they looked at: "breeding (including the use of wild-caught animals); transportation; housing; husbandry and care; handling; restraint; identification; adverse effects of scientific procedures (e.g. nausea from toxic compounds, discomfort and pain from induced syndromes, natural and experimental infections); and euthanasia."1

All these factors become magnified when considering primates in particular, because of their lifespan—up to 30 years for the commonly used rhesus monkeys. Largely because primates cost thousands of dollars each, they are typically 're-used' for experiments, traded between labs, and rented out. An article in the online magazine Slate called them "professionals—life-long civil servants."2 Not surprisingly, the negative impact of life as a research subject has a cumulative effect. Primates who survive multiple experiments and make it to, perhaps, 10 years old, have a trail of horrible experiences behind them. Re-use is also controversial because it raises questions about the validity of scientific results. An animal's reactions may not be to a current test, but to past exposures, which can alter body chemistry.

Who they are
The use of chimpanzees, who are apes, in research is rare and declining. But a few species of monkeys are commonly used in experiments.

New World monkeys (from Central or South America) used include marmosets, tamarins, and squirrel monkeys. Marmosets, from Brazil, with their characteristic white-tufted ears, are on the smaller side, weighing only about a pound. That makes them economical for labs due to smaller cage sizes. Cotton-top tamarins have a shock of white hair on top of their heads, contrasting with their black faces, and are slightly larger than their marmoset cousins. They are highly endangered and no longer exported (legally, at least) from their native Columbia. They became highly prized as research subjects because they can develop colon cancer, and were taken from the wild by the tens of thousands in the 1960s and 1970s.3

Squirrel monkeys are larger still—about 2 pounds, and much more commonly used, with a life expectancy of 20 years or so. Remarkably active, flying through trees, they may travel almost two miles in a day—an instinct utterly frustrated in a lab cage.

Old World monkeys (from Asia or Africa) used in research include vervet (or green) monkeys, baboons, and the most common, macaques. Adult male vervets reach over 15 pounds and their unique appeal to researchers is that they can develop high blood pressure. Baboons are much larger. Adult males average over 60 pounds while adult females are less than 40 pounds. A famous baboon use was in 1984, when a newborn infant, "Baby Fae," received a transplant with a heart that was taken from a baboon4—as much an experiment on Fae, who only lived 20 days.

By far the most sought after and widely used monkeys used in research are rhesus macaques, long-tailed (or crab-eating) macaques, and pig-tailed macaques. Much less bulky than baboons, adult male macaques will weigh only a little over 20 pounds and females only about 12 pounds.

What is done
Although the U.S. does not gather specific information on the types of experiments that primates are used for, the European Union (EU) does, and due to the similarity in their research enterprise, we can infer what primates are subjected to in U.S. labs.

According to the most recent EU statistics from 2008,5 toxicological and other safety testing accounts for 68 percent of primate use, with most of that for pharmaceutical drugs and devices. Another 13 percent of primate use is for research and development of new drugs and devices. Basic biomedical research accounts for another 13 percent.

In the U.S., although the pharmaceutical industry is certainly a dominant player in animal research, we might not expect quite the same numbers. It seems likely that basic research, the kind that goes on at universities, may account for a higher proportion of primate use than in Europe. The U.S. has a government-funded National Primate Research Center network with eight university-affiliated locations engaged in breeding and specialized experimentation. At these centers, cultivation of primate species as models is encouraged. For example, owl monkeys have been in limited use as a model for malaria research. If current attempts to improve breeding prove satisfactory, then they will surely gain popularity for other uses as well.

Chance plays a Role
In fact, the 'popularity' of one species over another is often due to access and not for scientific reasons. In the 1950s, India permitted hundreds of thousands of rhesus macaques to be exported to the U.S. for polio research.6 When they stopped the practice years later, scientists turned to other sources and then other species, meanwhile improving reproduction rates for those in captivity.

In recent years, scientists have called for locating primate research facilities in the countries where the primates are native, or at least nearby.7 China has become a major user, and exporter, of primates in research—sometimes for the same pharmaceutical and chemical companies based in the U.S. and EU.

Ultimately, funding priorities and technology influence how all science is conducted. When the Decade of the Brain was declared by President George H. W. Bush in 1990, the National Institutes of Health directed funding to brain research. The journal, Nature Neuroscience was launched in 1998 to publish papers resulting from the boom in experiments, many of which involved primates. Since then, we've seen that some of the monkeys who arrive at sanctuaries supported by AAVS have scars from implanted brain devices that have been removed before they were 'retired' from labs.

In another example, after the attacks on September 11, 2001, the U.S. instituted new programs to research much-feared chemical and biological agents and ways to combat their effects. At a conference 10 years after 9/11, I saw a scientific poster from New Mexico's Lovelace Lab showing a full-strength mustard gas experiment on monkeys, and I prayed that the monkeys never awoke from the anesthesia because their suffering would have been unimaginable.

Women's health research, genetic research, drug testing, vaccine testing, infectious disease research, addiction experiments, behavioral studies, and more all consume primates and the demand from experimenters for unfettered access continues to be strong.8 This was evident in Europe over the last few years during policy debates on animal testing. However, our EU advocacy partners posed tough challenges to regulatory requirements for primate experiments and achieved some concessions. Change will come as ethics provide the motivation and science provides the innovation to find alternatives to the shameful use of our primate cousins in science.

[1] Nuffield Council on Bioethics (2005) The ethics of research involving animals.
[2] Engber, D. (2009, June 5). Me and My Monkey: The confessions of a reluctant vivisector.
[3] Mittermeier, R. A., et. al. (2009). Primates in Peril: The World's 25 Most Endangered Primates 2008–2010. Primate Conservation 24: 1-57.
[4] Altman, L. (1984, November 16). Baby Fae, Who Received A Heart From Baboon, Dies After 20 Days. New York Times.
[5] European Commission. COM(2010) 511 final/2. Accompanying document to the Report From the Commission to the Council and the European Parliament--Sixth Report on the Statistics on the Number of Animals used for Experimental and other Scientific Purposes in the Member States of the European Union.
[6] Rowan, A. N. (1984). Of mice, models, and men, a critical evaluation of animal research. (pp. 110-117). State University of New York Press, Albany.
[7] Hau, J. and Schapiro, S.J. (2006). Non-human Primates in Biomedical Research. Scandinavian Journal of Laboratory Animal Science, 33( 1), 9-12.
[8] Ibid.

Read more from this issue of the AV Magazine
Ending the Use of Animals in Science