Up to this point each chapter has had a major area of research
or testing for its theme, but here the animals - nonhuman primates,
or primates for short - are themselves the subject. While it might
seem invidious to pick animals with the closest evolutionary relationship
to humans, rather than the dog, '.man's best friend," or
the whales and dolphins, aspects of whose intelligence appear
to rival our own, a number of circumstances add up to make the
plight of these animals altogether special. They are endangered
as a species; their activity, derived from an arboreal lifestyle,
condemns them to distressing physical restraint in the laboratory;
they are highly intelligent and sensitive; and probably the many
experiments they are subjected to in the U.S. have been statistically
surveyed more than that of any other species. Finally, as a result
of the recent breakthrough in teaching chimpanzees like Washoe,
Lana, Lucy and Sarah, and the gorilla Koko, to communicate through
sign language and other symbolic methods (Lana uses a typewriter),
in the not too distant future we may hear some comments from one
of these apes, perhaps not altogether complimentary, on human
behavior. (Bourne,G.,1977 and Hayes, H.,1977).
Because of these special factors, it is worth looking now at the plight of this one species as a whole, although numerous mentions of other experiments on primates will be found throughout the book and listed in the Index. This chapter may cause the reader to ask why we presume to treat our fellow-primates so abominably. Better ask ourselves before the apes do....
In June 1974 I visited the Animal Center Section, National Institutes of Health, Poolesville, Virginia. Dr. Albert E. New, then Head of the Primate Quarantine Unit there, let me observe the arrival of cages from India filled with rhesus monkeys - each cage only 2 1/2 ft. long x 1 3/4 ft. wide x 1 1/2 ft. high, crammed with seven animals weighing 4 1/2 to 6 1/2 lbs. apiece. They had been flown via London, where the small food and water containers in their cages had been refilled; nevertheless, they were very thirsty when they arrived by truck at Poolesville from the Washington airport. At the Center they had to be quarantined and treated for diseases, principally tuberculosis and shigellosis, which they were likely to have brought with them - diseases contracted from humans in their native land.
Five to six thousand monkeys a year were being received at
Poolesville at the time of my visit, and 75,000 were being imported
into the U.S. in 1973 for all purposes of these, about 55,000
were for biomedical use. The remainder were for exhibition and
the pet trade, but the total included an estimated 10,000 which
died during quarantine and 'conditioning.' The number of primates
maintained in the U.S. institutions in 1973 was estimated at 67,900.
During the development of polio vaccine in the late 1950's, the U.S. was importing rhesus macaques, alone, at the rate of 200,000 a year. During the years 1958-1976 over two million were imported. As a result of this high level of commercial exploitation, plus deforestation in the countries of origin, as well as expanding agriculture, urbanization and market hunting for meat, world primate populations were rapidly declining in the 1970's.
Concerned about the increasing scarcity of primates for biomedical research and Pharmaceutical production, the National Institutes of Health sponsored a study by the Institute of Laboratory Animal Resources, completed in 1975, on the current use and availability of these animals both in the.U.S. and abroad. (ILAR,1975).
This ILAR survey, from which most of the statistics in the
above paragraphs are taken, reports that losses of primates as
a result of collecting methods in countries of origin "have
been estimated by some to be as high as 50% of the numbers captured."
In 1967, 62% of vervet monkeys were estimated to have died during
collection in Kenya from a variety of factors, including death
"at the collecting station, death in unattended traps, young
released without their mothers, and the culling rate by dealers
who accept only animals of a specific size." The World Federation
for the Protection of Animals reports that in "Colombia and
Peru large areas are completely cleared of monkeys. Indians in
remote areas are now commercial hunters and trappers. Four or
five monkeys of even robust species die for every one successfully
exported." About 750 chimpanzees annually are required by
the world's laboratories but "for every chimpanzee which
reaches a laboratory six or seven others die during trapping,
holding by dealers, transport and quarantine. This brings the
total to about 5,000 ... which are sacrificed to science each
year." (Harrison, B., 1971).
The most conservative of the above estimates indicates that to produce approximately 65,000, net, primate imports used by the U.S. in 1973, another 85,000 animals, including the 10,000 which die in quarantine or in conditioning after reaching this country, were destroyed.
In Nov. 1976 international action resulted in all primates being placed either in Appendix I (species threatened with extinction) or Appendix II (species which may become threatened and for which regulation of trade is, therefore, necessary) of the Convention on International Trade in Endangered Species. This requires the exporting country, in every instance, to issue a certificate that shipment of the animals will not be detrimental to the survival of the species in the wild. (Smith, R.,1977).
Because of the diseases they transmit, but perhaps also in the hope of increasing the number available for research, the U.S. Dept. of Health, Education and Welfare several years ago prohibited the importation of primates except for scientific, educational or exhibition purposes. Nevertheless, even with the pet market eliminated, the decline in imports continued. In 1977 primate imports into the U.S. stood at 29,000, of which roughly one-third originated in India and were probably rhesus macaques. (Anon.,1978d, p.10).
In 1955 the government of India had banned the export of rhesus
monkeys as a result of fatalities during export. It was persuaded
to rescind the ban several months later, but at that time entered
into an agreement with the U.S. to insure humane treatment for
any primates which might be received from India in the future.
In the agreement India specifically prohibited the use of the
monkeys in atomic blast experiments and space research, allowed
their use in medical research and the production of antipoliomyelitis
vaccine, but required that each purchase order be certified to
this effect. There followed nearly two decades of rhesus imports
numbering well over a million animals, the time slipping by without
much attention being paid to what was happening to the monkeys.
Then came the development of the neutron bomb. Simulated radiation
effects of this weapon had been tested on various animals since
1966 at the Armed Forces Radiobiology Research Institute(AFRRI)
in Bethesda, Maryland, but it turned out, and was reported in
the Guardian (Tucker, A., 1977), and the Washington Post (Anon.,
1977b), that AFRRI had been using rhesus monkeys in these and
other experiments - in fact 1379 primates were known to have been
so used from 1972-1977.
The effects produced in these sensitive creatures by massive doses of radiation included diarrhea, vomiting (sometimes up to as much as 50 times an hour) and tremor, while their rapidly declining ability to function was tested on a treadmill on which they had been trained to run, or rather forced to run, in order to avoid punishing electric shocks. When they became too incapacitated to turn the treadmill, they were shocked, and if a "supralethal exposure" to radiation had been administered, this torture continued until death. (McGreal, S., 1978).
Representatives of the International Primate Protection League, as well as British humanitarians Muriel, Lady Dowding and Jon Evans,- brought this abuse of Indian rhesus to the attention of the Indian Prime Minister, Shri Morarji Desai. Other apparent violations of the 1955 agreement were also publicized in India, so, following an investigation of the whole matter of monkey export, the Prime Minister decided to ban the trade. This became effective on Apr. 1, 1978.
Recently, Shirley McGreal, Co-Chairwoman of IPPL, received new assurance on the ban from Prime Minister Gandhi. On Mar. 8, 1980, Mrs. Gandhi wrote:
"Dear Dr. McGreal, I have seen your letter of the 21st February about protection of Indian monkeys. We shall certainly do what we can to minimize cruelty to animals and also to humans. The ban on export of all types of monkeys from India continues and there is no proposal to reopen this now...." (McGreal, S., 1980).
These events have sent shock waves through the research establishment.
Hazleton Laboratories Corp., an international biomedical research
concern which along with Charles River Breeding Laboratories is
the largest importer of rhesus monkeys into the U.S., had an operating
profit of 30% on $1.2 million sales of these animals in fiscal
1978, but this extremely profitable part of Hazleton's $30 million
annual business nosedived after the ban: the company's research
animal sales were down 35% in the first nine months of 1979. However,
Hazleton and other importers turned quickly to Malaysia, Indonesia
and the Philippines for another source of primates, the cynomolgus
macaque (M. fascicularis), although a financial report on the
company laments that "the cynomolgus monkey is only marginally
profitable because of a high mortality rate in shipment and the
high price paid to exporters." (Roth, N.,1979, p.18).
However, despite the mortality, the importation of the cynomolgus, according to the U.S. Dept. of Commerce, was stepped up from 9,500 in 1977 to 16,100 in 1978, thus partly compensating for the rhesus ban, although the rhesus is still required by Food and Drug Administration regulations for vaccine testing. Primate imports were around 30,000 for both these years, to which must be added those born in the U.S. at N.I.H. Primate Centers, at Hazleton's Texas Primate Center, at Charles River Breeding Laboratories' Key Lois in Florida, and elsewhere - perhaps another 6,000.
The Interagency Primate Steering Committee estimates that "the
present breeding colonies of rhesus in the U.S. should yield a
net of 5,500 annually by 1980." (IPSC,1977,p.B-2). Thus the
contention of the International Primate Protection League seems
valid: that the appeal by "primate procurement politicians"
to officials of foreign countries urging them to release monkeys
for desperately needed polio vaccine testing is spurious, because
domestic production of rhesus is now sufficient to meet that need.
(Anon.,1979d,p.5). The motive is more likely a preference for
the cheaper imported rhesus, which cost about $250 before the
Indian ban as against the up to $800 now charged for the captive-bred
Including the rhesus mentioned above, the total U.S. federally supported production of primates projected to 1980 is estimated at 9,540 - see Table 1. (IPSC,1977, p.D-1). There has been some commercial breeding without government support, but since this has been relatively insignificant, there are still 28,000 primates to be imported if the present level of experimentation is to be maintained. What are the major biomedical uses of primates and how many of these are really necessary? The question must be considered against the background of species threatened with extinction throughout the world and the cruelty and wastage of animal life inseparable from the trapping and long- distance transportation of sensitive primates.
Key to abbreviations: DHEW: Dept. of Health, Education and
Welfare; ADAMHA: Alcohol, Drug Abuse and Mental Health Administration;
CDC: Center for Disease Control; FDA: Food and Drug Administration;
NIH: National Institutes of Health; DOD: Dept. of Defense.
1Supplies ADAMHA with approximately 100 rhesus monkeys per year.
The Interagency Primate Steering Committee identifies four main groups of activities in the biomedical use of primates, the 1977 requirement for which was estimated at 33,912 - see Table 2. (Ibid., p. A-4). I quote below from IPSCs National Primate Plan.
Key to abbreviations: See Table 1, p.117; also EPA:
Environmental Protection Agency; ERDA: Energy Reserve and Development
Administration; NASA: National Aeronautics and S-pace Administration;
NSF: National Science Foundation; VA: Veterans Administration.
1Other includes requirements of activities funded by state and local governments, foundations and academic institutions.
1. Legal and Regulatory
First biomedical use: "Legal and Regulatory. Procedures prescribed by law or regulation; e.g., those pertaining to production, potency testing, and safety testing of viral vaccine seed suspension and vaccine lots of licensed products."
The principle vaccine in this group is polio virus, the production and testing of which requires about 4,000 rhesus; approximately another 2,000 are required for the neurovirulence testing of other vaccines, including those for adenovirus, measles, mumps and rubella. Unless the vaccine is defective, the monkeys do not suffer since the injections (including the ones into the brain) are made under anesthesia and the animals are usually protected from the disease by the vaccine. The trouble here is that after a period of observation the monkeys have to be killed and their tissues examined to be sure no destruction of nerve tissue has occurred.
For a full discussion of the polio virus vaccine procedure and suggestions for reducing the numbers of animals used, see p.194 ff.
2. Biological Production
The second principal biomedical use of primates is described as follows: "Biological Production. Preparation of biological material such as experimental vaccines, tissue cultures, serum products, and biological diagnostic reagents. This includes activities using primates for production phases of these materials which are not specifically required by law or regulation." (Ibid., p. A- 2).
No more than 1,000 primates are used in this category: 800 by industry and 200 by the Center for Disease Control (among the operating components of the Center are the Bureaus of Laboratories, Tropical Diseases and Smallpox Eradication).
The Interagency Primate Steering Committee points out that primates were first used for these products when they were relatively abundant and cheap, in addition to being effective sources for the required material. Since the first two reasons no longer prevail, the Committee recommends that the users of primates reexamine the need for these animals "in recurring and production activities, ensuring that there is no acceptable alternative to their use and, where necessary, place increased emphasis on the development of new techniques and procedures in order to further reduce this need." (Ibid., p.12).
However, it should be added that the production of vaccines, antitoxins and hormone products, and the taking of blood or serum is not necessarily a painful experience for the animals concerned. The same cannot be said for the potentially very distressing testing of the virus or toxin for virulence in control animals which have not been protected by vaccine or antitoxin, see p.193-194.
3. Testing for Efficacy and Safety
The third biomedical use is "Testing. Evaluation of efficiency or safety of products for prophylactic, therapeutic and nutritional purposes. This includes activities concerned with efficacy and safety testing of vaccines prior to licensure, and of other compounds, materials, apparatuses, or other devices prior to approval for marketing." (Ibid., p. A-2).
In 1977, the distribution of primates for the above purposes was as follows: Center for Disease Control, 75; Food and Drug Administration, 220; Army, 250; Industry (Pharmaceutical/ Biological), 2,920; Total, 3,465.
When I visited the Food and Drug Administration's Bureau of Radiological Health, Rockville, Maryland, in 1974, I saw a number of these monkeys. Each was sitting on a wire floor in a small cage. They looked bored and listless, except for one who was jumping up and down and banging against the metal. They were being tested for the effects of radiation exposure - for instance, from a microwave oven. They had been trained to do some repetitive work, and each day they were rolled in a chair to the "workroom" to see whether their performance had been affected by the radiation.
Among the 250 monkeys assigned to the Army could well have been some of those who died in experiments at the Armed Forces Radiobiology Research Institute in Bethesda, Maryland, after exposure to up to 200 times the lethal dose of neutron radiation. The investigation sought "to model the effects of prompt external ionizing radiation on the physical performance capability of combat personnel...." As already mentioned, these monkeys were trained by electric shocks to run on a treadmill and their performance was evaluated before and after radiation. (Anon., 1979a, p.4).
An idea of the industrial testing which needs nearly 3,000 primates can be had by studying the annual reports of research facilities submitted to the U.S. Dept. of Agriculture under the provisions of the Animal Welfare Act. A rough check of the reports for the year 1976 reveals that about 1,100 primates are mentioned under the heading "Pain - no Drugs: number of animals involving pain or distress without use of appropriate anesthetic, analgesic or tranquilizer." There are numerous examples of animals trained to push a lever to avoid an electric shock, then given a drug to see whether it speeds up or slows down the avoidance rate. An example of a nutritional test is one performed by Hoffmann-La Roche of Nutley, New Jersey, on a group of 144 primates; the absence of pain relief was explained as follows:
"Induction of dietary deficiency disease by feeding subminimal diet. Test compounds are administered to evaluate their therapeutic activity. Anesthetics, analgesics and tranquilizers may interfere with test compound activity and obscure clinical evaluation." (USDA/APHIS,1976, Hoffmann-La Roche).
The rest of the primates, including thousands used by pharmaceutical
concerns, are enumerated in the annual reports under the Animal
Welfare Act, but, since their pain was either relieved by drugs
or was inconsequential, the nature of the experiments is not required
by the regulations to be further identified. No doubt many of
them were used in testing the "efficacy and safety of vaccines
prior to licensure."
The fourth major area of primate biomedical activity is Research. This is by far the largest area of use and in 1977 accounted for 22,497 animals. Instead of quoting the brief paragraph on the subject from the National Primate Plan, I turn to a more comprehensive description, in Nonhuman Primates, a publication based on a survey by the Institute for Laboratory Animal Resources on the usage and availability of primates for biomedical programs. The survey covered the year 1973.
This description begins with a mention of the three areas of use, vaccine production and testing, pharmacology, and toxicology, which we have already mentioned. These account for the first 38% of all primates.
"Studies of various diseases, including experimental surgery, account for the second largest demand, or 36 percent of the total primates. Cancer studies consume marmosets over all other species, including rhesus. Both marmosets and night monkeys are used in proportionately high numbers along with rhesus in studies of infectious diseases. This probably reflects the use of marmosets for work in hepatitis and night monkeys in malaria. Nearly as many baboons as rhesus are used in experimental surgery, which is striking when one considers their relative total numbers in use. Neurophysiological studies account for 16 percent and represent the second largest use for each of 3 species: the traditionally available rhesus macaque, the relatively large-brained squirrel monkey, and the night monkey, which is favored for its large eyes and nocturnally adapted retinas. The final 10 percent of total primates are used in physiological and behavioral studies." (ILAR,1975, p.37).
Malaria research has involved the use of the night or owl monkey (Aotus trivirgatus), particularly the North Colombia subspecies. They have become difficult to obtain because of dwindling populations as a result of habitat destruction. However, in 1976 Trager and Jensen at Rockefeller University succeeded in growing plasmodia, the parasites which cause malaria, as a continuous culture in a suspension of human red blood cells (Trager,W.,1976); it has since been possible to make the parasites complete their life cycle in laboratory culture. This should provide an alternative to the use of the monkey as a model for the disease process. Research is continuing in the hope of developing a vaccine from the gametocytes (sexual stage of the parasites) which infect mosquitoes from human blood. This could prevent the transmission of the disease to these insects. A further development may produce a vaccine which will protect an individual from the bite of an already infected mosquito.
The use of the rare marmoset monkey in hepatitis A research has been mentioned. Up to now, only the livers of this diminishing South American species have been suitable for culturing the virus of infectious hepatitis. An alternative technique of growing the virus - on cell cultures originally taken from the kidney of a rhesus monkey fetus - has recently been announced by P. Provost and M. Hilleman, at the Merck Institute for Therapeutic Research. Unfortunately, fetal rhesus monkey cells stop reproducing after 12 population doublings in culture and are therefore less than ideal for growing large quantities of the virus from which a live vaccine has to be prepared. However, the experiment has shown that it is at least possible to do this on cell culture, thus sparing the marmoset. Because of the many human sufferers from this worldwide disease, it is hoped that eventually a suitable cell will be found to make vaccine preparation a reality. (Provost, P.,1979).
There is something repulsive in the idea of keeping animals alive for as long as they can "last out" during a series of surgical or other procedures. At least in the form of "practice surgery" this has been banned in Great Britain since the Cruelty to Animals Act came into being in 1876, although there is a loophole: if what is being done can be described as an "experiment," it is legal. Unfortunately, recycling of primates has been vigorously advocated in the U.S. ever since the supply here began to diminish (30,000 available in 1978 as against 55,000 in 1973). Experimenters say they have to do it in order to conserve endangered species, and because primate models have become so expensive. Thus in a 1974 statement from the Division of Research Resources, NIH, investigators were asked "to use their nonhuman primate subjects to the maximum. Whenever feasible, scientists should use an animal for several studies." (Anon.,1974,p.l). An exhortation to do likewise, "as monkeys become more expensive," appeared in the NIH-sponsored ILAR Nonhuman Primates (ILAR,1975,p.12). However, in this publication there is some recognition of the need for improved caging to make the lives of the primates being subjected to this high-pressure research more bearable. It suggests
"... new designs for laboratory holding cages that will accommodate the changing patterns of primate research, particularly the increased length of time for which animals are held and the increased frequency with which both long-tailed and arboreal species are utilized. (For example, sliding doors between compartments would provide convenient means for isolating individual animals for examination, false floors of proper height above the substrate could prevent the tails of long-tailed species from becoming soiled with water or feces, and the addition of perches would allow for normal foot and tail postures.)" (Ibid., p.8).
The 1977 National Primate Plan continues to urge "multiple
use and recycling" and proposes a "users' service"
which will facilitate the transfer of primates to other facilities
when the original laboratory has run out of ideas. (IPSC,1977,
A painful dilemma - subjecting one group of animals to maximum stress in order to save a larger group from another kind of stress, or even destruction. The only solution is a renewed effort to help both groups by pressing the hunt for alternatives to replace this "end justifies the means" type of exploitation.
One of the primate's misfortunes is the fact that he shares with humans an unwillingness to be tethered like a cow or leashed like a dog. This means that in many experiments he must be under physical restraint, sometimes continuously for months, in a device which reduces this lively and playful creature to straightjacketed near-immobility (Fig. 1). Even worse for a social animal is what frequently follows: isolation in sound-shielded cubicles - boxes 3 to 4 feet high, about 2 feet wide and only deep enough to allow a primate chair to be rolled in. (BRS/LVE,1976). Here are excerpts from two typical experiments:
1. Harvard Medical School (M.C. Moore-Ede and J. Herd): "The studies were performed using six adult male squirrel monkeys .... For periods of up to 3 wks. continuous urine collections were obtained from unanesthetized monkeys, conditioned to sit in a specially designed metabolism chair within an isolation chamber .... The monkey sat on a bar and was restrained by a Plexiglas sheet which served as a table around its waist." The experiment traced the daily rhythm of excretion of water, sodium and potassium in chaired monkeys. (Moore-Ede, M.,1977, p.F128-F129).
2. Walter Reed Army Institute of Research (J.W. Mason): Fifteen monkeys were placed in restraining chairs, and each chair was then isolated "inside a sound resistant, dimly illuminated, blower-ventilated booth. Urine collection was initiated immediately upon placement of all monkeys in the restraining chair and was continued throughout the full 8-week period that the monkeys remained in the chair." The experiment documented the monkeys' emotional response to the stress of chair restraint by noting the increase in cortiocosteroid excretion. This increase is associated with a physiological stressful situation. (Mason, J.,1972, p.1292).
3. Yerkes Primate Research Center, Atlanta, Ga.: Studies on the wasting of muscles caused by restraint and inactivity in rhesus monkeys. (Anon.,1977a, p.1).
Fig. 1. Monkey in restraint chair. (Courtesy: International Primate Protection League).
Although there are certain procedures, for instance an experiment
such as No. 1 which involved a continuous metabolic study, and
No. 3, which by design require chair restraint without a break,
primates are sometimes housed in chairs for long periods merely
to avoid the bother of capture in the home cage and transfer to
and fro. However, techniques now exist which make such permanent
restraint unnecessary in most cases. Glassman, Negrao and Doty
at the University of Rochester describe a procedure by which macaques
can be kept in their home cages yet easily and safely put into
primate restraining chairs when they are needed for testing. The
chairs are designed so that they can be attached when required
to the door of the cage where the monkey is living, and the monkey
is drawn into the chair by means of a chain which, in a protective
plastic tube, encircles his neck. (Glassman, R.,1969).
Nevertheless, in studies of bone loss as a result of total body immobilization, or of weightlessness in space experiments, monkeys may be immobilized for a matter of months in restraint systems. W.H. Howard and associates, who, in National Aeronautics and Space Administration study on bone resorption, kept monkeys immobilized for 10 weeks in a kind of nylon straightjack et on an aluminum frame, summarized some of the alternate methods.
"Nerve sectioning has been used by some workers; however, because of its essentially irreversible nature, it was considered inappropriate for the present studies. Splints and casts have been used, but they are inconvenient for routine examination for abrasions, sores and general body condition. With a cast there would still be a problem of housing the animal on a stand or carriage with attendant accessory equipment. Pillory-neckplate type restraining chairs used in behavioral studies are constructed of hard materials and would seem at the outset not well suited for long-term restraint. Indeed, these have been reported to cause edema, psoriasis, and decubital ulcers when the animal was restricted to a sitting position." (Howard,1971, p.112).
Doty, in an editorial in Experimental Neurology, also comments on this:
"In very few, if any, instances is it necessary for the restrained animal to be forced into the abnormal posture of sitting in the style of Western man or of holding its chin at 90o with respect to the spine; yet many primate restraining devices thoughtlessly impose this posture on their occupants." (Doty, R.,1975, p.ii).
Finally, I quote comments of Donald Barnes, a psychologist who worked for 16 years, up to 1980, at the School of Aerospace Medicine, Brooks Air Force Base, and became very critical of the experimental use of primates there. Speaking of restraint in behavior modification by electric shock, he said:
"The restraint devices used are barbaric in themselves: e.g. metal couches with metal neck, belly, and ankle restraints. As the animal struggles to free itself, it often loses its teeth to the neck bar, gains severe abrasions on the abdomen (often wearing entirely through the abdominal wall), or so severely chafes its ankles that they bleed and become infected; and the animal is shocked and shocked again (sometimes hundreds and hundreds of times per day), until it either does the experimenter's bidding or is 'flunked out' to another program requiring no training." (Anon.,1980f).
Neurophysiological studies accounted for 16% of the experiments
in the ILAR survey. These are experiments which investigate any
of the special senses (seeing, hearing, etc.) or the brain centers
controlling them, or the central nervous system and its affiliated
nervous networks: peripheral, somatic and autonomic, or the neurochemicals
like norepinephrine and acetylcholine which act as neurotransmitters.
The primate, because he is cousin to man, with a brain and nervous
system similar in many respects, is a favorite target of the neurophysiologist.
In June 1974 I visited the Laboratory of Neurophysiology at
the National Institute of Mental Health, Bethesda, Maryland and
talked to its chief, Dr. Edward V. Evarts. A thin, keen-appearing
scientist with a Harvard background, he was investigating the
brain mechanism controlling muscular movement in monkeys.
His technique was to insert permanent stainless steel bolts through the monkey's skull, one on the left and one on the right side, and a steel cylinder through the top of the skull. The latter allowed access to a microelectrode so small in caliber that, while the monkey performed a series of wrist movements, the instrument was able to record the activity of single nerve cells in the motor cortex and other regions of the brain. During the manipulation, the monkey was restrained in a chair with his head immobilized by the skull bolts attached to clamps on either side.
The monkey was trained to make the desired wrist movements through responses to a signal light; correct responses were reinforced by rewards of fruit juice delivered through a mouth tube. Dr. Evarts said that in this procedure monkeys can be trained by rewards but not by punishment. Some species cannot be trained at all; he recalled one monkey of a particularly affectionate type which became very hurt when they attempted to restrain him. The rhesus, while often aggressive, responds well under the sympathetic management of a good animal handler. Sometimes they would go by themselves to sit in their chairs (anticipating, I assume, the juice reward). I saw one merely restrained in a chair - "getting accustomed to it;" - when I looked in he bared his teeth at the unfamiliar presence but when I passed again on the way out he appeared to be asleep. As for the steel bolts, Dr. Evarts maintained that these were no worse than those implanted in the necks of people who had crushed cervical vertebrae.1
The monkeys used were young - preadolescent or adolescent. They never grew old, being killed after one year of life to permit examination of the brain tissue.
In an article in Scientific American published the year before my visit, Dr. Evarts described his experiments and suggested that they were producing a better understanding of the role of the deeper brain centers, such as the cerebellum and basal ganglia, and their relation to the cerebral motor cortex. Since these deeper centers are implicated in motor disturbances in humans, for instance in Parkinson's disease, he suggested that "a particularly promising area of investigation for the near future is the analysis of experimentally produced motor disturbances in monkeys." (Evarts, E.,1973).
This courteous scientist in his attractive office with Japanese prints and a Harvard chair, speaking of his appreciation of the personality differences of his monkeys and then introducing me to his kindly technician, tempted me to feel that the lot of these primates, compared to that of many other experimental animals, was not too bad. But when he writes about "experimentally produced motor disturbances," it reminds us that there is another aspect to neurophysiology - one which does not content itself with the mere recording through microelectric probing of relatively insensitive brain units.
This other, darker side of neurophysiology is largely concerned
with the effects of mutilations of various parts of the nervous
system to see what functional disturbance results. Cats, because
of their cheapness and availability, are more commonly used, but
primates are by no means neglected. Since any mutilation
(by deliberate surgical or electrolytic damage) causes some loss
of function, there is always something to describe, and the variations
At Yale University Medical School, the home of much brain mutilating "aggression" research (see 1D.20,41), Y.H. Huang caused electrolytic lesions in the locus coeruleus (a brainstem structure) of nine stumptail macaques. The locus is one of the "pleasure centers," and is so-called because gentle electrical stimulation of this area is remarkably titillating. It is rich in norepinephrine, one of the neurochemicals associated with stress and emotional reactions, and, sure enough, when all the monkeys were killed a month later, norepinephrine in the damaged area was much diminished. (Huang,Y.,1975). The experimenter had no hesitation, apparently, in sacrificing the lives of all these primates. Was there no alternative? M. Schlumpf and his associates may have found one- they have succeeded in growing norepinephrine-containing neurons of the locus coeruleus of the rat's brain in culture. The authors state that norepinephrine and dopamine levels can be measured by radio-enzyme assays in vitro, and claim that these cultures are we'll suited for neurophysiological recording, as well as morphological, biochemical and pharmacological experiments. (Schlumpf, M., 1977).
Alas for Yale's nine stumptail macaques!
Another fairly common procedure is directed not at the brain, but at the afferent nerves which transmit sensation from the limbs to the brain. These nerves are cut, "deafferented," in various limbs of young, newborn or fetal monkeys to see what effect it will have on their movements in later life. (Taub,E., 1976). The public can learn about the operative procedure and the crippled monkeys which result in a film produced (1968) by the National Society for Medical Research, ANIMAL SECRETS - HOW THE MIND BEGINS. In the film, inexplicably narrated by the writer-philosopher Loren Eiseley, the deafferentation of a monkey fetus is hailed as an "historic" advance, likely to aid (in some vague way) in the understanding and prevention of birth defects and mental retardation. However, as frequently happens in films vaunting medical research, and not infrequently in scientific papers, one gains the impression that it is the ingenuity of the operative technique which is the raison d' être for the presentation rather than any tangible therapeutic benefit.
On the other hand, the blinding of primates is not a procedure publicized in films promoted by defenders of animal experimentation. In this book, examples have been given in the chapter entitled, "Behavior- Deprivation Experiments," p.47-48.
Finally we come to behavior studies - not the comparative few
involving observations in the field along ethological lines as
conducted by Goodall, Schaller and others, but behavior modification
in the laboratory, which more accurately might be called behavior
This subject, including the use of primates, has already been discussed in the chapters on behavior, P.31-80, but here are two further illustrations.
Donald Barnes, whose comment on physical restraint has already been mentioned (p.128), left the School of Aerospace medicine at Brooks Air Force Base, San Antonio, in 1980, having become increasingly critical of the inhumane experimental work there. As a psychologist, he had participated for 16 years in experiments subjecting primates to ionizing radiation injury and to nerve gas (organophosphate) poisoning - an investigation which has recently become more interesting to the Air Force than radiation studies. The onset and degree of poisoning is measured by impairment in the animal's performance of behavioral tasks. After leaving, - Mr. Barnes made a statement to the International Primate Protection League, of which the following is an excerpt.
"I can no longer perform experiments with animals doomed, by virtue of their participation in such experiments, to a very early death, if not to pain and suffering, during the final weeks and months of their existence.
From 1966 until mid 1978, I performed innumerable experiments with rhesus monkeys, and 2 or 3 such experiments with baboons. In each experiment, 6 to 12 subjects were trained by the use of electric shock to perform a task of human design, i.e., not within the primate's normal behavioral repertoire. It is no simple task to train a rhesus monkey to complex visual, auditory, and tactile-kinesthetic discrimination. Although the papers written to report such experiments claim that very low level shock is utilized as reinforcement, (3-5 ma), such statements are simply untrue. It may be that 3-5 ma is sufficient for maintenance of acquired behavior, but such current levels are far below those required to initiate early responses approximating the desired behavior.
The shock generators are designed and manufactured by BRS (Behavioral Research Systems) and deliver at least 50 ma at 1200 volts. I couldn't even guess at the number of times I've seen these units used at full power to punish a slow learner or to otherwise 'reinforce' undesirable behavior: well into the thousands; however, the learning process is replete with other dangers for the monkey as frustration leads to other self-destructive behaviors, e.g. biting hunks of meat from an arm or hand, pulling out hair until the subject is bald in accessible spots."
Once it has been trained in this fashion, the animal is irradiated or fed the toxic substance, and the onset and degree of poisoning is measured by impairment in the animal's performance of the behavioral tasks - often by its decreasing ability to avoid repeated, painful electric shocks. (Anon.,1980f).
For other experiments of this type, using strong electric shocks, see p.138.139.
After recording this long saga of abuse of primates, it is a relief to recall that there are some very remarkable experimental alternatives which have opened up new insights into primate mentality and behavior. These are the experiments mentioned on p.110, teaching primates to communicate through various symbolic methods. Two fine films have been made on the work with the chimp Washoe; for reviews, discussion and distributor, see the Argus Archives publication, Films for Humane Education, (Scott, R.,1979). A film has also been made on Penny Patterson's work with the gorilla Koko. Koko has been taught to communicate through sign language and has a vocabulary of several hundred words. The sophistication of some of these exchanges is illustrated by the following anecdote:
"Three days after Koko had bitten Patterson in a fit of anger, she asked the ape (in sign language), 'What did you do to Penny?' Koko replied, 'Bite.' 'You admit it?' Patterson asked. Looking a little contrite, Koko said, 'Sorry bite scratch.' Patterson then asked Koko why she had bitten her. 'Because mad,' came the answer. 'Why mad?' 'Don't know.' The conversation ended." (Leakey, R.,1978, p.53).
A large literature has appeared on this research, which has implications not only for nonhuman primates, but also for a better understanding of the development of the brain and language in human primates. And yet, at the very moment when we seem to be on the verge of opening an astounding new channel of communication with our nearest relatives in the animal kingdom, the relentless population decline among the apes is accelerating. As Eugene Linden, in his excellent book, Apes, Men and Language, puts it:
"It would be unutterably sad to let any of these animals disappear. After so long, we have a lot to talk about. Perhaps they are the first and last creatures who can tell us who we really are." (Linden, E.,1975, p.196).
But this benign and civilized research commands only a minute proportion of the funds spilled out of the federal purse into the eager hands of the generality of primatologists. The kind of experiments which many of them prefer is illustrated by the following retrospective bibliography (1910-1974) of 582 stress and aversive (fearful or punishing) behavior experiments on primates. It was not compiled as "ammunition" for antivivisectionists but, on the contrary, was apparently intended to aid (and perhaps suggest ideas to) investigators engaged in similar research. The aversive events which these sensitive animals are subjected to include:
"air (pressurized and wind), alien species (human, human staring, and snake), aversive drugs, crowding, darkness, electrical stimulation of the brain, gravitational forces, hitting, isolation, looming, noise, nonreward (frustration), pinching, pricking, radiation, restraint, sandpaper, sensory deprivation, shock (electric), slapping, social defeat (induced experimentally), strobe light, tastes (foul), temperature extremes, threat of social separation, time-out from positive reinforcement, unavoidable aversive events, unpredictable stimulus changes, vertical chamber confinement, visual cliff, and water (rain)." (Stoffer,G., 1976, p.18).
1. Also, Dr. G.H. Bourne, when he was Director of Yerkes
Primate Center, is quoted as saying that the permanently implanted
electrodes are not irritating, since monkeys do not attempt to
remove them. "If you had something there that was causing
pain, the animal would be scratching and pulling at it."
(Stilley, F.,1975, p.74).
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