They usually work in a grid pattern until they encounter scent of the missing person, and then follow that scent on the wind until they locate the person. They are effective in finding a lost or missing person in large areas or thickly vegetated areas where human searchers would take considerably more time. Area search dogs are not typically scent specific (like a trailing dog) and will locate any human scent in a search area. They are very effective for covering large search areas with high efficiency and accuracy.
Area search dogs must have the ability to work independently from their handler and search large areas for any live human scent. Area search dogs begin their training with puppy ‘run-aways’ where the handler motivates the dog with a favorite toy or food treat and then simply runs away in a straight line a short distance to hide behind an object. The young K-9 then is released to go and find their handler, at which point the K-9 receives a huge reward for locating the subject. They are trained in much the same way as a bird dog, but instead of hunting upland game, they are taught to hunt for and find live human scent. It is basically a big game of hide-and-seek and the K-9 learns that finding the live human in the woods means a huge reward in the form of a toy or food treat. As the K-9 progresses through their training, they are increasingly challenged with more distractions, more difficult terrain and weather conditions, and multiple ‘victims’ to mimic real-life scenarios. A properly trained area search dog is taught to return to its handler upon location of the subject to give a trained indication, and to then lead the handler back to the location of the subject. This allows the K-9 to work at great distances from the handler while still ensuring that they will notify the handler when they have located the subject.
See SAR K-9 Standards with the International Police Work Dog Association