Chimpanzees Used in Research
by Steven J. Schapiro, Ph.D.
Michale E. Keeling Center for Comparative Medicine and Research
Our group at the University of Texas has pursued techniques to refine the handling and management of non-human primates in the laboratory for several years now, with the direct goal of enhancing their welfare. We also try to improve the manner in which the research is done on the animals, because we feel animals with enhanced welfare are better research subjects, as they are less likely to be adversely affected by stress. We study both the behavioral and physiological effects of psychological factors related to the management and research use of nonhuman primates, including how training chimpanzees to cooperate with biological sampling procedures can make research with chimpanzees better.
Training techniques, especially those focusing on positive reinforcement procedures, provide captive primates with some control over what happens to them—a part of their natural existence typically difficult to provide in captivity. Our project aimed to determine whether voluntary participation in blood collection procedures affected physiological values in the blood of chimpanzees.
Preliminary analyses of older data indicated the technique used to collect blood from the animals affected a number of physiological values. We found the values obtained when subjects voluntarily presented themselves for an anesthetic injection appeared to indicate they were less stressed than in the samples obtained when the anesthetic injection was non-voluntary (in most cases this meant the anesthetic was administered using a dart gun). The latest project was designed to directly address whether blood collection procedures influence these values.
Our subjects were seven adult chimpanzees living in different-sized social groups. All were trained to provide a voluntary, unanesthetized blood sample using a blood sleeve device (simply a plastic tube for an animal to put an arm in). The tube had a handle at the far end for an animal to grip, and the cut-out portion on its top provided safe access to a vein in the arm. A chimpanzee would place an arm in the sleeve, hold it still and allow us to draw a blood sample. When he or she cooperated with the procedure, the chimpanzee would be rewarded with food.
Voluntary blood samples were obtained two or three days before the collection of an anesthetized blood sample, and the physiological values were compared across the two samples per subject. Although we were really trying to compare unrestrained (voluntary) to restrained (anesthetized) samples, the way our experiment was designed made it difficult to make this comparison in the absence of the effects of the anesthesia—so another way to look at the study is as a comparison of unanesthetized to anesthetized samples. Our study demonstrates it is possible to train multiple chimpanzees to voluntarily provide a conscious blood sample, and our findings show the technique used to acquire the blood sample affects many important physiological values.
Incidentally, we hope you are wondering why stress-related hormones such as cortisol have not been mentioned. We are somewhat uncomfortable with the use of cortisol as a measure of stress in nonhuman primates, yet we are in the process of analyzing cortisol and some other relevant factors from the samples that we have collected. These results should considerably enhance our ability to interpret our findings.
This study is important in our continuing quest to refine the techniques we use when working with nonhuman primates, especially chimpanzees. We still need to do more, but we assume voluntary sampling techniques using animals trained with positive reinforcement techniques are better for the animals and better for science. We always try to demonstrate studies will more directly address experimental hypotheses when more refined techniques are used to handle and work with the animals; better data obtained from subjects trained to cooperate with research procedures should accomplish this goal.