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Research

The Beginnings

Chimpanzee captured in net
Chimpanzee captured from the forest, name unknown
Photographer: Gilbert Rollais, Courtesy of: Edward Hooper

Sometime in 1697 or 1698 a young chimpanzee was captured from the forests of Angola (a country on the west coast of Africa), packed in a crate on board a ship and arrived in London. This fateful day was the beginning of a long and dark history for chimpanzees and science.

The chimpanzee broke a tooth on the voyage, developed an infection in his jaw, and died. Edward Tyson, England’s leading anatomist, then performed the first known detailed comparative anatomical dissection on a chimpanzee. His results, published in 1699, focused much attention on the anatomical similarities between Homo sapiens and other primate species. (1)

By the early 1700s, Europeans began keeping chimpanzees as “pets” and some attempts were made to teach them to speak. There was much speculation regarding the relationship between humans and chimpanzees and whether, with training, they might be able to function in human society as servants and laborers. (2)

Behavior which counts as specifically human

Throughout the eighteenth and nineteenth centuries, most research focused on questions regarding our evolutionary relationship with nonhuman primates and the cognitive abilities (awareness and judgment) of chimpanzees.

The first modern investigations into chimpanzee cognition may have been those conducted at the anthropoid station established by the Prussian Academy of Sciences at Tenerife in the Canary Islands. There, scientist Wolfgang Kohler carried out what became classic studies of chimpanzee problem-solving recorded in his 1925 book, The Mentality of Apes. According to the renowned primatologist Jane Goodall, Kohler’s insights “remain among the most careful, perceptive, and important in the literature.”

Kohler was the first researcher to document chimpanzees’ ability to manipulate objects (such as poles, ropes, and boxes) in a creative and functional manner to get food positioned beyond their reach. (3)

Chim, Panzee, Bill, Dwina, Pan, and Wendy

American psychobiologist Robert Mearns Yerkes was responsible for the first significant use of chimpanzees for research in the United States. Yerkes gained recognition as the author of several books about great apes including Almost Human, in 1925. He regarded chimpanzees’ abilities with amazement, but this did not stop him from promoting their use as research tools.

In 1923, Yerkes purchased two young chimpanzees whom he named Chim and Panzee. They both died within the year. Following their deaths, he bought two more young chimpanzees, Bill and Dwina. In 1925, he purchased two additional young chimpanzees and named them Pan and Wendy.

These four individuals—Bill, Dwina, Pan, and Wendy—were the first of thousands of chimpanzees to be used by U.S. scientists in research. (4)

In 1930, Yerkes obtained support from Yale University and several foundations to establish a primate research center in Orange Park, FL. The facility became known as the Yale Laboratories of Primate Biology. Upon Yerkes’ retirement, Yale renamed the facility the Yerkes Laboratory of Primate Biology. (5)

In 1956, after Yerkes’ death, Emory University assumed ownership of the Orange Park laboratories. The facility was later moved with the help of NIH funding to the Emory campus in Atlanta. (6)

The earliest research at the Orange Park facility was a continuation of the work pioneered by Kohler. Yerkes was genuinely interested in this area of research and noted that the processes of chimpanzee learning would eventually be identified as antecedents of human symbolic processes. Nevertheless, even as scientists continued to discover profound similarities between human and chimpanzee minds, they remained eager to use them in painful and potentially lethal experiments.

Gaining momentum in the U.S.

By the mid 1930s, experimental neurologists and psychologists were promoting the increasingly invasive use of chimpanzees. In 1937, J.F. Fulton, MD, a researcher associated with the Yale Laboratories of Primate Biology, delivered a presentation to the Kansas City Academy of Medicine titled, “The Chimpanzee in Experimental Medicine.” Fulton said:

…[T]he gorilla is so rare as to be no longer available for experimental purposes. I have longed to have one, or possibly two gorillas on which to compare certain cortical reactions to ablation with the corresponding reactions in the chimpanzee. However, a living gorilla in this country now fetches anywhere from $3,000 to $10,000 so the price is entirely prohibitive….

The chimpanzee… can be purchased for scientific purposes for prices which fluctuate during the year from $100 to $400. (7)

Fulton went on to promote the chimpanzee as an experimental subject in studies on vision, the nervous system, sex, and reproduction.

By the 1940s, research papers describing various experiments using chimpanzees were becoming more common. The following excerpt in which a researcher destroyed various parts of chimpanzees’ brains and observed the resulting symptoms, serves as an example of the experiments chimpanzees were forced to endure:

One of these [chimpanzees] had seriatim ablation [surgical removal] of frontal association areas, caudate and putamen. Following the first operation removing left areas 9-12 of cortex together with the head of caudate and much of the putamen there were involuntary irregular twitches of head and right arm for about 48 hours. There were then no signs of motor abnormality whatsoever. The second areas 9-12, caudate and putamen were then removed. Following this there was again a brief period of involuntary twitching, but no paresis [partial paralysis], and then a fine tremor which appeared about three days after operation and continued till death two weeks later from diarrhea. The second of these animals, ill before operation and chosen for experimental trial because of this, had area 6 and caudate removed from first one side and then the other. Following the first procedure there were contralateral involuntary twitches of a few days’ duration. It died immediately after the second.

The third had the largest lesions of caudate and an additional lesion in each putamen together with removal of area 6 with an eight months interval between operations. After each there was true chorea [progressive loss of neuronal functioning]—lasting about a month in each instance—most severe in the arm, but involving head, and to a lesser extent, the leg on the side contralateral to the lesion. The chorea was, in both instances, so severe as to prostrate the animal for some days. It was the only true chorea seen. Following the second operation and as the paresis disappeared, a pronounced bilateral tremor became obvious, which lasted the remaining months of its life. (8)

Polio: one of the first failures

During the 1940s, chimpanzees were used in research on poliomyelitis conducted at the Yerkes Laboratory of Primate Biology in Florida. Throughout the 1940s, young chimpanzees, aged 1-4 years, were fed or inoculated with poliovirus. Some had been bred in captivity at the Yerkes lab; others were captured from Africa. (9)

As with most infectious diseases which afflict humans, chimpanzees can carry the poliovirus without developing symptoms of disease. Even their carrier state does not last long and the virus disappears after a short period. Most do not become sick at all.

One study, which spanned 1946-50, utilized 18 chimpanzees in studies of polio infection and observed how “There were no signs of weakness or paralysis in any of the animals. Sixteen of the eighteen (89 percent) became infected as measured by intestinal carriage of virus.” (10)

Eighteen chimpanzees were used; they were exposed to various strains of poliomyelitis virus a total of 54 times. Eight of these animals were subjects in previous similar experiments. Nine of the animals, ranging in age from 12 months to about 4 years, were born and had always lived in the Yerkes Laboratory of Primate Biology, Orange Park, Florida, before coming to our laboratory. The other nine, aged approximately 2 to 4 years, were obtained from a dealer who had imported them from Africa. (11)

For this study, viral strains of polio were obtained from human stool specimens associated with known polio outbreaks. Other specimens were taken from spinal cords of monkeys infected with polio. One set of specimens was described as “fly contaminated food collected in epidemic areas in North Carolina and New York.” (12)

These varying specimens were fed to chimpanzees and/or inoculated into their skin. Chimpanzees were deemed carriers if their stools tested positive for virus. Most did not develop any signs of illness. Jada, a female, developed fever and an upper respiratory infection 13 days after receiving the virus and died. However, her necropsy showed that her death was caused by hemorrhagic pneumonia.

The 18 chimpanzees in this experiment were housed in single cages so that stool specimens could be obtained by means of individual collection pans. After collecting the stools, specimens were purified and injected into the brains of rhesus monkeys to see if they would develop polio. Not surprisingly, many of these monkeys died not from polio, but from infective brain abscesses. Death from infection was reduced once the researchers combined the injections of polio extract with antibiotics. Polio research using chimpanzees appears to have stopped around 1950.

In the next decade, more chimpanzees were captured from Africa, destined as subjects for air and space research. Read: Air & Space


Sources

(1) Nash, R. Tyson’s Pygmie: the Orang-outang and Augustan ‘Satyr.’ In Ape, Man, Apeman: Changing Views since 1600. Corbey, R and Theunissen (Eds.) Evaluative Proceedings of the Symposium Ape, Man, Apeman: Changing Views since 1600. Leiden, The Netherlands, June 28 -July 1, 1993. 51-62.

(2) Corby, R., and Theunissen, B., eds. (1995) Ape, Man, Apeman: Changing Views since 1600. Evaluative Proceedings of the Symposium Ape, Man, Apeman: Changing Views since 1600, Leiden the Netherlands, 28 June—1 July, 1993. Department of Prehistory, Leiden University.

(3) The Mental Life of Monkeys and Apes: A Study of Ideational Behavior. The Johns Hopkins University; Behavior Monographs. Volume 3, Number 1, 1916 (156).

(4) Yerkes, RM. Chimpanzees: A Laboratory Colony. Yale University Press. 1943.

(5) Guide to the Robert Mearns Yerkes papers, Manuscript Group 569, compiled by Bruce P. Stark, December 1983.

(6) “Innovation and Science: The History of Yerkes.” Available at: http://www.yerkes.emory.edu/about_history.html

(7) “The Chimpanzee in Experimental Medicine.” Reprinted from “Transactions of the Kansas City Academy of Medicine, 1937, 1938, 1939.” [pp 2-3 passim] in Section of Primate Physiology, Laboratory of Physiology. Yale School of Medicine. Collected Papers July 1, 1939—June 30, 1940. Volume VII. Paper # 239.

(8) Kennard, MA. Experimental analysis of the function of the basal ganglia in monkeys and chimpanzees. J. Neurophysiology, 1944, 7:127-148. In Volume XI (July 1, 1943—December 31, 1944) of the Collected Papers of the Section of Primate Physiology. Laboratory of Physiology, Yale University School of Medicine.

(9) Horstmann DM, Melnick JL. (1950) Poliomyelitis in chimpanzees; studies in homologous and heterologous immunity following inapparent infection. J Exp Med. Jun 1;91(6):573-97. Available at http://www.jem.org/cgi/reprint/91/6/573

(10) Ibid. Page 596

(11) Ibid. Page 573

(12) Ibid. Page 577

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