How Can Search Dogs Help?
Search dogs can help law enforcement and managers of emergency services by providing skilled and qualified dogs to perform a variety of tasks using their amazing noses—which are 100 times more sensitive than a human’s:
Also known as article search. Dogs can be trained to search for specific scents (bomb dogs, arson dogs, narcotics dogs, etc.) Dogs have even been trained to detect cancer cells in the human body, and seizure dogs can warn their owners when a seizure is on the way.
Evidence dogs are most often trained to find items with human scent in a wilderness environment (e.g. cell phones, wallets, gloves, keys, etc.) Wind and weather dissipate the fresh human scent over time. The longer the item is in place, the more difficult it becomes to detect. Depending on the item and conditions, most evidence dogs can still detect items placed 2-3 days ago—some even longer. Fresh human scent or trails left by searchers passing through the area does not affect the dog’s ability to locate the item, which is its own scent source. Before the dog searches the area, however, and while he is searching, the area should be cleared of any additional scent-generating sources, such as human searchers combing the area.
The certified evidence dog is also trained to find any article that is “out of place” in its environment. An item tossed into an open field not only bears human scent, but retains its own scent (plastic, metal, chemical, paint, paper, whatever) which is gradually dissipated while it absorbs other scents around it, till eventually it becomes a part of the environment. The dog will find items with human scent in the wilderness, but his “out of place” training also enables him to identify items that have been recently added to an urban environment filled with human scent (e.g. stolen currency stashed in a warehouse).
Lost Person Location
There are basically two ways that dogs use scent to find a lost person:
Tracking/Trailing Dogs follow a scent trail left along the route where the person recently passed. Some dogs track the missing subject by following his footprints from the point last seen (PLS), using the scent of the crushed vegetation and other disturbances to the surface where the subject’s feet have made contact as well as the scent of the person leaving the track. More commonly, dogs trail their subject, using the scent that explodes off each person from all over his body, leaving an invisible cloud of scent that hangs in the air above the track and gradually drifts away from the track, depending on conditions. Thus trailing dogs will often work parallel to the actual track left by the subject. Both tracking and trailing dogs typically work in harness, on a long lead, as they follow scent.
Area Search Dogs find the lost subject by air-scenting, which process is also known as wilderness search or area search. It is not necessary for the air-scenting dog to be anywhere near the track left by the subject, nor to have a point last seen (PLS). These dogs work off-lead, ranging widely as they search large areas for airborne human scent, which spreads from the subject’s current location, moved by wind, temperature, and air pressure in varying directions from the scent source. When the dog hits even faint traces of the spreading scent, he will follow it back to its source, and then alert his handler (by whatever trained means he has learned) that he has found the subject. In some cases the dog will return to the handler to lead the handler back to the subject’s position. Area search K-9 teams do not search randomly; they are usually assigned sectors with varying degrees of probability of detection of the lost or missing person.
A sub-category of air-scent training is urban/disaster search for live victims in the aftermath of a tornado, hurricane, earth\quake, flood, or terrorist attack. Area search dogs are also used to cover disaster scenarios, since they employ the same skills in locating hidden victims in buildings and under rubble as they use in wilderness search. However, additional training on rubble and unstable surfaces, agility training and directional command training are strongly recommended.
Human Remains Detection (HRD). Also known as cadaver search.
Land HRD dogs are trained to search for the different types of scent that we associate with a person who is no longer alive. Human remains detection dogs must not only find strongly scented source materials; they must also alert on such items as hair, fingernail clippings, teeth, or band-aids with a few drops of blood from an accidental cut. HRD dogs can locate materials that are suspended or buried, as well as human remains that are at ground level.
Water recovery dogs search for drowning victims or the remains of subjects submerged in water. Scent from the remains rises through water, and dogs work from a boat, searching for traces of the surfacing scent as they cover likely areas of the stream or lake. Some HRD-trained dogs alert from the shoreline, using airborne scent, to help pinpoint a submerged scent source.