Resourceful canine handlers have found that dogs can be trained to detect human remains long after death., despite burial or attempted concealment. Trained dogs are able to distinguish between human remains, animal remains, and a wide range of other odors that would normally be expected to distract them. Thus, their ability to distinguish between sources of similar biological odors enhances their application in the area of Human Remains detection (HRD)...Bodies buried, disarticulated bodies, bodies submerged in water, or hidden in vehicles or structures have been efficiently located by HRD teams.Cadaver dogs are trained to use their powerful sense of smell to locate a missing body. The dogs can do this because as a dead body decomposes it gives off gasses with a distinct smell. The dogs are taught to recognize and alert to this smell, even in very small concentrations, and to follow the smell to its source. The gasses will even rise through the earth from a buried body, or up through the water from a drowning victim.
Humans shed millions of microscopic skin cells (called rafts) on a continual basis. As a person moves along, these particles leave an invisible trail that is detectable to a dog. Some fall to the ground or catch on blades of grass, trees, or other obstacles, while some are carried along on air currents. The closer the dog is to the 'victim' the more concentrated this trail becomes.