JOURNAL OF APPLIED BEHAVIOR ANALYSIS 2015, 48, 1–10 NUMBER 1(SPRING) TRAINING POUCHED RATS TO FIND PEOPLE KATE B. LA LONDE WESTERN MICHIGAN UNIVERSITY AMANDA MAHONEY,TIMOTHY L. EDWARDS,CHRISTOPHE COX, AND BART WEETJENS ANTI-PERSOONSMIJNEN ONTMIJNENDE PRODUCT ONTWIKKELING AND AMY DURGIN AND ALAN POLING ANTI-PERSOONSMIJNEN ONTMIJNENDE PRODUCT ONTWIKKELING AND WESTERN MICHIGAN UNIVERSITY Giant African pouched rats equipped with video cameras may be a tenable option for locating living humans trapped under debris from collapsed structures. In the present study, 5 pouched rats were trained to contact human targets in a simulated collapsed building and to return to the release point after hearing a signal to do so. During test sessions, each rat located human targets more often than it located similar-sized inanimate targets on which it had not previously been trained and spent more time within 1 m of the human target than within 1 m of the other targets. Overall, the rats found humans, plastic bags containing clothes, and plastic bags without clothes on 83%, 37%, and 11% of trials, respectively. These findings suggest that using pouched rats to search for survivors in collapsed structures merits further attention. Key words: urban search and rescue, Cricetomys gambianus, scent detection, detection animals Acts of war and terrorism, natural disasters, years to train, are inconvenient to transport, and engineering mistakes, and inadequate mainte- are limited in their capacity to localize the source nance can cause buildings and other structures of human scent (Chiu et al., 2002; Wong & to collapse, potentially trapping people under Robinson, 2004). Moreover, because of their size, debris. Rapidly locating, extricating, and treating dogs typically cannot penetrate rubble, but are these individuals greatly increases the likelihood limited to searching for scent as they move over of their survival. Currently, organized search and and around debris (Federal Emergency Manage- rescue relies primarily on human search teams ment Agency, 2012). that use visual and auditory cues to find victims No proven technique is available for searching (Wong & Robinson, 2004). Trained dogs are through and under debris without the time- also widely used (Chiu et al., 2002; Wong & consuming process of manual or mechanical Robinson, 2004). Although useful, dogs can take rubble removal, and experts have recommended the evaluation of the use of small mammals for This study was supported by U.S. Army Research Office this purpose (Wong & Robinson, 2004). The Grant W911NF-11-1-0464. Dissertation research grants present study explored whether giant African from the Association for Behavior Analysis International provided partial support for the activities of Amanda pouched rats (Cricetomys gambianus) could be Mahoney and Amy Durgin. trained to search for people and to return to their Please address correspondence to Kate La Londe (e-mail: release point after hearing an auditory signal. [email protected]) or Alan Poling (e-mail: alan. [email protected]). Cricetomys are agile, nocturnal, burrowing ani- doi: 10.1002/jaba.181 mals native to sub-Saharan Africa that climb well; 1 2 KATE B. LA LONDE et al. therefore, they should have no difficulty moving 2010; Poling, Weetjens, Cox, Beyene, & Sully, through, over, and around debris. Like dogs, they 2010), a similar training strategy was used in the have a highly sensitive sense of smell, and they present study. have been trained through operant conditioning procedures to detect land mines (e.g., Poling, METHOD Weetjens, Cox, Beyene, Bach, & Sully, 2010; Poling, Weetjens, Cox, Beyene, & Sully, 2010; Subjects, Materials, Setting Poling et al., 2011); to detect the presence of The study took place in Morogoro, Tanzania, Mycobacterium tuberculosis, the bacillus that at the training facility of Anti-Persoonsmijnen causes tuberculosis, in human sputum (e.g., Ontmijnende Product Ontwikkeling (APOPO, Mahoney, Weetjens, et al., 2012; Poling, “Anti-Personnel Landmines Detection Product Weetjens, Cox, Mgode, et al., 2010; Weetjens Development”in English). APOPO is a Belgian et al., 2009); and to detect Salmonella bacteria in nongovernmental organization that uses the scent- horse feces (Mahoney et al., 2014). The rats are detecting ability of pouched rats for humanitarian relatively inexpensive to transport, house, and purposes (see APOPO.org for details about the maintain, are not dependent on a single human organization). Ethical clearance to conduct the handler to work well, and maintain accurate study was obtained from APOPO’s Institutional performance during long periods of repetitive Animal Care Use and Committee. Five pouched work. Moreover, they live 8 or more years in rats (Van, Graca, Torres, Chi Chi, and Ram) captivity, so trained rats can provide valuable served as subjects. The rats, which were selected service over a protracted period, and they are large for the study as newborn pups, came from enough (adults typically have a body length of 25 APOPO’s breeding colony. APOPO began its to 45 cm and weigh 1 to 2 kg) to carry appropriate colony with wild-caught rats and for over a equipment in search-and-rescue applications. As decade has been producing rats for use as we currently envision it, this equipment would research animals and operational land-mine- include a video camera to record images screened and tuberculosis-detection animals. The rats for evidence of living people as soon as a rat exited were experimentally naive and were fitted with a debris and a beeper to signal the rat to return to its subcutaneous passive integrated transponder to release point after a specified search time. A small ensure accurate identification. They were light (not used in the present study) would also be housed in pairs in cages with unlimited access carried to allow a visual-light camera to operate to water and a nest box until Stage 2 training (see and to inform survivors that the rat is a trained below) began, after which they were housed search animal, not a wild scavenger. Rats could individually so that each rat received the proper also carry a reassuring printed message to that amount of food. From the beginning of Stage 2 effect. to the end of the study, on Monday through Given their physical characteristics, and Friday rats were fed only during sessions. On assuming that they can be appropriately trained, Friday afternoon each rat was given a carefully Cricetomys may be useful for searching through weighed weekend allotment of food (e.g., rubble for living humans. In view of our success peanuts, watermelon, small fish, and bananas), in training operational land-mine detection rats and any food not eaten was removed Sunday by exposing them to a series of training stages that morning to ensure proper food deprivation for develop appropriate responding under conditions Monday’s training. During training (Stages 2 that ever more closely resemble the environment through 4) and probe sessions, 45-mg food in which the rats will work operationally (see pellets combined with smashed bananas were Poling, Weetjens, Cox, Beyene, Bach, & Sully, delivered through a large syringe to reinforce POUCHED RATS FIND PEOPLE 3 correct responses. Sufficient food was earned in forced to move over and around objects to sessions so that subjects gained weight over time traverse the room and reach targets. at approximately the same weight as control animals not involved in experiments. Depriva- Design tion of food from the end of each session, or from A discrete-trials within-subjects probe design Sunday morning, to the beginning of the next (Poling, Methot, & LeSage, 1995) was used. In experimental session was an effective establishing this design, after training Stages 1 through 4 were operation for food as a within-session reinforcer. completed and rats reliably located human targets Moreover, bananas are highly preferred food for and returned to the starting location after hearing pouched rats. an auditory signal, each rat was exposed to a Three kinds of targets were used: (a) humans, series of probe trials, each of which provided the (b) large plastic bags filled with recently worn opportunity to find one of three types of targets. clothing (jeans, shirts, and shoes), and (c) large One of the targets was a human, as in training. plastic bags filled with air. Human targets Another target, a plastic bag containing clothes consisted of 15 men and five women, ranging worn by a human with some clothing draped from 15 to 45 years of age. They were residents across the outside, was intended to provide visual of Tanzania, Kenya, the United States, and and olfactory stimuli similar to, but less salient Belgium. During training stages, human targets than, those provided by a human. The third rotated daily and within sessions. During probe target, an air-filled plastic bag, was intended to trials, both previously used and novel human differ substantially from a human. If the rats were targets were used, with the same human never actually searching for humans, not simply serving on more than one trial per rat per day. blundering into them by chance, then they The plastic bags were 30-gallon capacity and should more readily find humans than either of were changed periodically during probe trials. the two other targets and should find the bag The clothes had been worn for 1 day within containing clothes more readily than the air-filled 3 days of probe sessions by someone who was not bag. Comparison of overall detection rates within a target and were handled by nontarget humans rats and across target types provides a means of wearing latex gloves. The plastic bags were determining if this occurred. An alternative handled by humans wearing latex gloves. The arrangement, in which one of each type of target bags and clothing were not present during was presented on each trial, could have been used, training Stages 1 through 4 and were therefore but the present arrangement was selected to novel stimuli during initial probe trials.