LABORATORY PRIMATE NEWSLETTER Vol. 47, No. 1 January 2008 JUDITH E. SCHRIER, EDITOR JAMES S. HARPER, GORDON J. HANKINSON AND LARRY HULSEBOS, ASSOCIATE EDITORS MORRIS L. POVAR, CONSULTING EDITOR ELVA MATHIESEN, ASSISTANT EDITOR ALLAN M. SCHRIER, FOUNDING EDITOR, 1962-1987 Published Quarterly by the Schrier Research Laboratory Psychology Department, Brown University Providence, Rhode Island ISSN 0023-6861 POLICY STATEMENT The Laboratory Primate Newsletter provides a central source of information about nonhuman primates and re- lated matters to scientists who use these animals in their research and those whose work supports such research. The Newsletter (1) provides information on care and breeding of nonhuman primates for laboratory research, (2) dis- seminates general information and news about the world of primate research (such as announcements of meetings, research projects, sources of information, nomenclature changes), (3) helps meet the special research needs of indi- vidual investigators by publishing requests for research material or for information related to specific research prob- lems, and (4) serves the cause of conservation of nonhuman primates by publishing information on that topic. As a rule, research articles or summaries accepted for the Newsletter have some practical implications or provide general information likely to be of interest to investigators in a variety of areas of primate research. However, special con- sideration will be given to articles containing data on primates not conveniently publishable elsewhere. General descriptions of current research projects on primates will also be welcome. The Newsletter appears quarterly and is intended primarily for persons doing research with nonhuman primates. Back issues may be purchased for $10.00 each. We are no longer printing paper issues, except those we will send to subscribers who have paid in advance. We will not accept future subscriptions, unless subscribers are willing to pay $100/year. (Please make checks payable to the Brown University Psychology Department.) Readers with ac- cess to electronic mail may receive a notice when a new issue is put on the Website by sending the message sub- scribe LPN-WARN your-own-name to [email protected]. (Send the message subscribe LPN-PDF to receive PDF files by e-mail; or the message subscribe LPN-L to receive the nongraphic contents of each issue.) Current and back issues of the Newsletter are available on the World Wide Web at <http://www.brown.edu/primate>. Persons who have absolutely no access to the Web, or to the electronic mail- ing, may ask to have paper copies sent to them. The publication lag is typically no longer than the three months between issues and can be as short as a few weeks. The deadline for inclusion of a note or article in any given issue of the Newsletter has in practice been somewhat flexible, but is technically the tenth of December, March, June, or September, depending on which issue is scheduled to appear next. Reprints will not be supplied under any circumstances, but authors may reproduce their own articles in any quantity. PREPARATION OF ARTICLES FOR THE NEWSLETTER. – Articles, notes, and announcements may be submitted by mail, e-mail, or computer disk, but a printed copy of manuscripts of any length or complexity should also be sent by regular mail.. Articles in the References section should be referred to in the text by author(s) and date of publication, e.g., Smith (1960) or (Smith & Jones, 1962). Names of journals should be spelled out com- pletely in the References section. Latin names of primates should be indicated at least once in each note and article. In general, to avoid inconsistencies within the Newsletter, the Latin names used will be those in Mammal Species of The World: A Taxonomic and Geographic Reference, 2nd Ed. D. E. Wilson & D. M. Reeder (Eds.). Washington, DC: Smithsonian Institution Press, 1993. For an introduction to and review of primate nomenclature see the chapter by Maryeva Terry in A. M. Schrier (Ed.), Behavioral Primatology: Advances in Research and Theory (Vol. 1). Hillsdale, NJ: Lawrence Erlbaum Associates, 1977. All correspondence concerning the Newsletter should be addressed to: Judith E. Schrier, Psychology Department, Box 1853, Brown University Providence, Rhode Island 02912 [401-863-2511; FAX: 401-863-1300] e-mail address: [email protected] Current and back issues of the Newsletter are available on the World Wide Web at http://brown.edu/primate ACKNOWLEDGMENTS The Newsletter is supported by Brown University Cover photograph of a Douc Langur (Pygathrix nemaeus), taken at the San Diego Zoo by Paul G. Wilde, June 1997 Copyright © 2008 by Brown University Nonhuman Primates Mask Signs of Pain Roland Plesker1 and Valentin Mayer2 1Paul-Ehrlich-Institut, Langen, Germany and 2 Medical doctor, Egelsbach, Germany Introduction consists of more individuals and they have access to two or three of these cages, attached to each other in one It is known that wild animals have good reasons to room. Usually, different species of primates are kept in mask signs of pain and illness in nature. First, they might different rooms (but there are two exceptions). be priority targets for predators if they show signs of pain or illness. Second, social-living individuals might lose Recording of behavior and wounds: When any signs of their social rank if they do not appear to be perfectly fit. injuries/illnesses were detected in the monkey colony When kept in captivity, the question of whether ani- (blood in the cage, blood or wounds detected, strange be- mals mask signs of pain is important for monitoring their havior of individuals), experienced animal caretakers or health. Since there are no generally accepted objective veterinarians observed the particular monkey for at least criteria for assessing directly the degree of pain that an five minutes to detect and describe its actual behavior ac- animal is experiencing (Morton & Griffith, 1985), indirect curately. The observed behavioral changes were scored criteria must be used. For example, changes from the according to the following criteria: species-specific “normal” behavior can be used as an in- 0 = no detectable behavioral changes; 1 = slight dication of pain (Smith et al., 2006; ILAR Committee on behavioral changes such as slow motion of one ex- Pain and Distress in Laboratory Animals, 1992, p. 41). tremity, behavior otherwise normal; 2 = obvious behavioral changes, such as avoiding use of one arm It can be difficult to recognize pain in primates since or leg, slight depression; 3 = severe behavioral they will often appear to show little reaction to it (Wolf- changes such as clear apathy or unconsciousness. ensohn & Honess, 2005, p. 60). Also, experts know that conscious nonhuman primates frequently mask signs of Afterwards, the monkeys were anesthetised (general pain (Fortman, et al., 2001, p. 115; ILAR Committee on ketamine-xylazine anesthesia) and the wounds or illnesses Pain and Distress in Laboratory Animals, 1992, p.41). were described in detail by veterinarians. Photos of the However, it is difficult to prove this scientifically, since injuries were usually taken. The injuries/illnesses were animals cannot communicate in ways that can be readily independently scored according to the following criteria: understood by people (Hughes & Lang, 1983; Soma, 1 = only skin affected in a single wound; 2 = mus- 1987). cles involved in a single wound or multiple wounds; 3 = significant loss of tissue or general body condi- In this study, we try to compare primate behavior after tion affected. detection of wounds or illnesses to imagined human be- havior in “comparable situations”. Moreover, we try to Imaginary comparison to humans: For comparison of compare both behaviors to the “objective” severity of the monkey behavior to imagined human behavior, an ex- wounds or illnesses in an attempt to prove, scientifically, perienced medical doctor was consulted who had no ac- whether primates really mask signs of pain routinely. cess to the monkey behavior scores. Dr. Mayer was told the sex and age group (e.g., juvenile) of each “patient” Animals and Methods and the sizes of the wounds were translated to human di- Animals: The primate colony at the Paul-Ehrlich-Institut mensions. Photos of the monkey wounds were used to in Langen consists of 144 nonhuman primates (62 males, give a better notion of the wounds in the imagined hu- 82 females): 57 African green monkeys (Chlorocebus mans. The doctor was also told that the imagined patient aethiops = 40%), 41 rhesus macaques (Macaca mulatta = could not speak to explain the pain. He was asked how 28%), 21 pig-tailed macaques (Macaca nemestrina = human patients of similar (relative) age and size and of 15%) and 25 cynomolgus monkeys (Macaca fascicularis the same sex would behave if they came to him with those = 17%). They are group-housed in an experimental in- wounds or illnesses, and he answered on the basis of his door facility. experience with human patients. A five-minute “observa- tion period” of the imaginary human behavior followed, There are 38 cages, made of steel; each is 300 cm x during which the behavioral changes the doctor expected 125 cm x 225 cm. The animals are mostly housed in to find in each situation were scored as described above harem groups (1 male and 2-3 females with their off- for the monkeys’ behaviors. spring). Sometimes a group of this size is restricted to one cage (the only cage in a room); sometimes the group Results Monkeys: Fifty-eight cases of injuries/illnesses in non- First author’s address: Paul-Ehrlich-Institut, Abteilung 4 ZT, P.- human primates were reported in a six-month period. Of Ehrlich-Str. 51-59, 63225 Langen, Germany [e-mail: these, 54 cases were included in the study. Three cases [email protected]]. 1 were excluded because a wound was detected on the end Discussion of the tail only; in one case the definite reason for illness- When wild animals are kept in captivity, it is ex- related behavioral changes could not be determined.