rounding up sheep to assisting the visually impaired, which are of great importance to special economic interests or nar- row segments of the population. Specially bred and trained working dogs are critical front-line assets in military and law enforcement functions such as suspect apprehension, ex- plosives detection, and narcotics interdiction, so dogs have a particularly pervasive influence on life in the developed world, especially in this dangerous age of terroristic threat and globe-spanning, low-intensity warfare. Working police and military dogs are employed in large numbers throughout the nations of Western Europe and North America, and they are increasingly being adopted by governmental agencies in much of the rest of the world, including Asia, Australasia, South America, and Africa. As in the case of humans, it is be- coming clear that some individuals are better suited to some tasks than are others (Wilsson and Sundgren, 1997,1998; Murphy,1998;Slabbert and Odendaal, 1999;Serpelland Hsu, 2001; Svartberg, 2002). We summarize findings from a project using personality to predict performance in explo- sive detector MWDs at Lackland AFB. Study 1 shows that interval-scaling methods yield reliable measures of personal- ity; strong reliability coefficients were obtained across be- haviors assessed. Study 2 shows that behavioral codings made by non-experts from videotaped behaviors agree with codings made by experts. Study 3, a field-task analysis, pro- vides information about factors influencing performance in the field. Discussion focuses on how the research can illumi- nate links between personality and work performance and can be used to improve selection and training of MWDs. 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Sci 64, 269–28 Svartberg, K., 2002.Shyness-boldness predicts performance in working dogs.Appl.Anim.Behav. Sci.79,157–174. Vazire,S., Gosling,S.D.,Dickey,A.S.,Schaprio, S.J., 2007.Measuring personality in nonhuman animals. In: Robins,R.W., Fraley,R.C., Krueger, R.F. (Eds.),Handbook of Research Methods in Personality Psychology. New York,Guilford, pp. 190–206. Wilsson,E., Sundgren, P.-E.,1997.The use ofa behavior testfor the selection of dogs for service and breeding, I: Method of testing an uating test results in the adult dog, demands on different kinds of dogs, sex and breed differences. Appl. Anim. Behav. Sci. 53, 279– Wilsson,E., Sundgren, P.-E.,1998.Behaviour testfor eight-week old puppiesdheritabilities of tested behaviour traits and its correspond to later behaviour. Appl. Anim. Behav. Sci. 58, 151–162. WILL THE SWEDISH POLICE BE ABLE TO FIND TRACKING DOGS IN THE FUTURE? Lasse Eriksson* Swedish Police Dog Centre, Karlsborg, Sweden *Corresponding author: eriksson-lasse@telia.com The Swedish police buy all their dogs on the open mark About400 of our police dogs are trained for tracking. Of these, 300 are German shepherds (GS). About 50% of the police dog missions in Sweden are track related. Most missions take place in urban environments, but trackin 10 km in forest terrain isnot uncommon. Therefore, trackingitself has to be self-rewarding for the dogs. However, ability to track isnotmuch considered when selecting breeding stock. Of the about2900 GS born annually in Sweden, only 14% (year 2000) participate in trials that include some kind of tracking. According to o experience, 10%-20% of the Swedish GS have a desire tracking that is sufficient for police service. From several hunting breeds, we can learn that tracking ability can be clearly improved by selective breeding. Therefore, it is of interesto consider if tracking ability will diminish with time if not selected for. If this is the case, there is a risk the Swedish police will find iteven more difficult to find competent GS tracking dogs in the future. Key words: tracking;police dog; Germanshepherd; breeding EFFECTS OF EARLY REARING ENVIRONMENT ON BEHAVIORAL DEVELOPMENT OF GUIDE DOGS D.L.Duffy,J.A. Serpell* Center for the Interaction of Animals and Society, Department of Clinical Studies, School of Veterinary Medicine, Unive of Pennsylvania, Philadelphia, PA 19104 *Corresponding author: serpell@vet.upenn.edu We compared puppies that had been exposed to one of differentrearing environments during the first8 weeks post-whelping: 240 Journalof Veterinary Behavior, Vol 4, No 6, November/December 2