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INTRODUCTION
Chimpanzees, because of their close evolutionary relationship to humans, are attractive models for physiological, biomedical, and behavioral studies. For example, they have participated in such important developments in the category of "national needs" as the development of vaccines against hepatitis B and in early aerospace programs. A current census maintained by the International Species Information System (ISIS) indicates that of about 2,500 known captive chimpanzees globally, about 1,500 are housed in six biomedical institutions in the United States. In 1986, the National Institutes of Health (NIH) launched a breeding and research program at five institutions for several basic reasons: a perceived need for these animals for AIDS research, concerns about the potential for sustaining future generations of breeding chimpanzees, and concerns about the ability to provide sufficient animals to meet other national needs. The effort met production goals, and an initial breeding population of 315 animals has produced 394 live births. Of these offspring, 331 were alive in February 1997 (176 of which remain in the NIH breeding program). The combination of an increase in chimpanzee numbers and smaller than expected use of chimpanzees in research, has created a substantial management problem that jeopardizes both the chimpanzee model for research (because of their high cost) and their quality of care in research facilities (because of reduced funding). All animals that constitute the research and breeding pool now owned or supported by NIH require provisions not only for the short term, but also for long-term maintenance, regardless of their use in research. However, the funding required for long-term maintenance of a sizable population of chimpanzees
is considerable. Concerned with the burgeoning population of chimpanzees, the stress that the additional animals have created on available facilities, and issues associated with long-term care of captive chimpanzees, NIH asked the National Research Council to study these and related problems. Captive chimpanzees are behaviorally complex and have an average life span of 25 yr for males and 34 yr for females (maximal life spans are 55 yr and 65 yr for males and females, respectively), and their long-term management presents formidable challenges.
The challenges are not simply scientific or financial. The form and substance of this report reflect the fact that questions of science and questions of ethics are often inextricably blended. The very feature that can make the use of chimpanzees critical in biomedical research also entails unique moral questions. On the one hand, chimpanzees constitute a vital scientific resource for research on critical issues of human health, and proposals for their long-term care must not undermine the availability of adequate numbers of them for such research. On the other hand, the complexity of the ethical and scientific challenges follows from the fact that chimpanzees are our closest genetic relative in the animal kingdom. These two factors—scientific use and close genetic relative—cannot be divorced; one cannot appeal to one and ignore the other.
The dilemma of why or whether chimpanzees ought to occupy a special niche in moral deliberations relative to their experimental use cannot be reduced to an either-or situation. It is not simply a question of whether the chimpanzee is "just" another animal or otherwise equal in all respects to a human being. We believe that relevant differences between chimpanzees and humans justify the use of chimpanzees in research that would not be sanctioned if it were proposed to use human subjects. However, the close phylogenetic relationship to humans and complex psychological and social character of chimpanzees that make them more similar to humans than other laboratory animals are also relevant.
The conclusions reached by the authors of this report are based on scientific, financial, and ethical reasoning. Although the scientific and financial arguments might be more understandable to many readers of the report and are sufficient justification by themselves in reaching a decision for some readers, the ethical issues are also important and should be seriously considered, in our opinion. In the traditional sense, ethics requires that decisions be based on clearly articulated core human values—concepts
of right and wrong, good and evil, taking responsibility for one's choices—that go beyond purely pragmatic or economic considerations. Portions of the committee's recommendations are based on this concept, which, through numerous discussions with members of the public and the scientific community, led to our endorsement of the premise that the similarity of chimpanzees to humans distinguishes them in substantial ways from other laboratory animals and implies a moral responsibility for the long-term care of chimpanzees that are used for our benefit in scientific research. This special status of chimpanzees is supported by the following considerations of medical science, genetics, population biology, cost, and perception.
The similarities between chimpanzees and humans that make them desirable surrogates for studying diseases and conditions of humans constitute the reason for our recommendation for their continued use in scientific research. The committee believes that chimpanzees have provided and will continue to provide important scientific contributions, but that requires a captive population of sufficient size to sustain breeding and research. Unlike many other species used in research, chimpanzees cannot be recovered quickly if the population is disbanded or allowed to be reduced below a critical size. That is true for several reasons: their listing as endangered in the wild by the US Endangered Species Act and their listing in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) make importation from the wild impossible; their long generation time of about 10-yr makes recovery of a population time-consuming, expensive, and unresponsive to research demands; and recovery from cryopreservation of chimpanzee embryos or gametes is not yet possible. The need to maintain a healthy population is an important aspect of our responsibility for the care and well-being of chimpanzees used for scientific research.
We believe that our responsibility for the long-term care of chimpanzees is greater than that for other laboratory animals. Chimpanzees are genetically very similar to humans (Morin and others 1994). The special connection of chimpanzees to humans has been reinforced by decades of watching the rich repertoire of chimpanzee social, maternal, and tool-using behavior on television and at zoos; the public therefore expects a high level of respect for the animals. Our view is that this special status of chimpanzees implies a moral responsibility for appropriate long-term
care of chimpanzees used in scientific research. Therefore, recommendations are provided for their life-time care. This view definitely has financial consequences, and the committee recognizes such a position is not embraced by everyone.
The issue that perhaps best articulates the result of the committee's ethical position and the other major recommendations of the report is the manner in which the animals are treated after they are no longer needed for research or breeding. If these animals are euthanized on completion of their usefulness to the research enterprise, many of the expensive and complex issues discussed in the report will not exist. Because of the considerations reviewed above, the committee could not agree to euthanasia for population control. One member of the committee provides a thoughtful counter argument (see Appendix A).
We believe that responsibilities for the long-term care of chimpanzees are shared by both the scientific community and society in general. The issues associated with long-term care are intertwined: We cannot say that "this" is purely the responsibility of scientists and "that" is the sole responsibility of society. Societal needs warranted the past research with chimpanzees and will demand future research on emerging disease threats. These considerations must be appreciated if the committee's task is to be understood in its proper social context.
These considerations must be appreciated if the committee's task is to be understood in its proper social context. The National Research Council asked the committee to:
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Gather information from the biomedical institutions where chimpanzees are housed, from scientists at large, from animal welfare organizations, and from the general public.
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Prepare ethically and scientifically balanced cost-effective recommendations for a strategy for long-term care of chimpanzees in biomedical and behavioral research.
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Provide recommendations that strive to ensure a population adequate for research needs to enhance public health while promoting chimpanzee conservation and well-being.
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Address issues of policy, including relevant aspects of animal welfare, ethics, and public-private interactions, and recommend whether, or under what conditions, euthanasia is an acceptable means
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of population control and whether government-owned animals might be transferred to private sanctuary facilities.
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Recommend funding mechanisms for long-term care facilities (government and nongovernment).
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Identify types of studies using animals not actively involved in research that would be beneficial to the public health, aid in conservation of the species, and be acceptable to managers of sanctuaries who receive funds from public donations.
On the basis of the charge and the committee's findings, this report provides recommendations pertinent to six interrelated questions:
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What are the current and future needs for chimpanzees in research?
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How will research needs affect the breeding population?
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How should the current and future populations be housed and managed?
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What are the estimated costs of high-quality long-term care of the chimpanzee population?
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Can the federal government, industry, and the public work together toward solutions?
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How can quality in both research and long-term care be kept at the highest possible levels?
The principles that the committee developed to guide its recommendations are as follows:
An adequate population must be maintained because chimpanzees constitute an important resource that can be used to protect the national health against emerging infectious diseases and a useful model for many kinds of biomedical and behavioral research, including research to develop vaccines and therapies for major human diseases. There is a critical need for long-term policies for proper care, housing, and management of captive chimpanzees—policies that would ensure the well-being of this population beyond the immediate future.
The body of this report consists of five chapters. Following is a brief overview of the content of these chapters.
Chapter 2, "Research Needs," analyzes the needs for chimpanzees in biomedical and behavioral research. This chapter is based on discussions among members of the committee and with scientists, directors of the government-supported chimpanzee facilities, and members of the public; surveys of the chimpanzee facilities; and literature reviews. It concludes that chimpanzees have made and should continue to make substantial contributions to biomedical research. The chapter summarizes some of these contributions and includes estimates of future requirements for chimpanzees based on the number used in recent studies related to important viral diseases.
Chapter 3, "Long-Term Care," recommends standards for ensuring the well-being of chimpanzees in long-term housing, divides the US chimpanzee population into six groups, and offers specific recommendations for each group. A brief description of types of successful and unsuccessful housing is followed by recommendations. A section on euthanasia provides a discussion of the pros and cons of this procedure relative to chimpanzees.
Chapter 4, "Genetics, Cost, and Demography," discusses the genetic management of the US biomedical chimpanzee population and the current and expected costs of caring for the various groups of chimpanzees. Recommendations are provided regarding inbreeding and the desired size and demography of breeding colonies to sustain the population for future research. Two models are presented that discuss the costs, options, efficiencies, and liabilities associated with each of two possible management options. The two models estimate the numbers of animals needed in the breeding colony and not needed for breeding. Associated costs of the subpopulations in the models are provided to assist in management decisions. Record-keeping is discussed as an essential element of the genetic management of these colonies, and the role of cryopreservation is addressed.
Chapter 5, "Centralization of Research Chimpanzee Management and Development of a National Chimpanzee Resource," describes the rationale and a mechanism for centralizing all aspects of managing the chimpanzee population with the goal of ensuring its cost-effective maintenance and use. Ways to implement the recommendations, provide financial support, and establish continued oversight of all facets of the chimpanzee resource are discussed in the context of federally funded colonies and privately owned (nongovernment) sanctuaries.
