Human Remains Detection, or HRD, is also a part of airscent in the sense that the dogs are working to locate remains by taking in and processing the air around them. Unlike live-find, the scent changes depending on the stage of decomposition, which is why HRD dogs require specialty training.

HRD Dogs work alongside their handler in close proximity to strategically and systematically search through an area. Trained dogs are capable of disregarding the odor of animal remains and differentiating between a human bone and that of a deer or elk for example. Due to the high level of training required handlers work diligently to maintain their skills.

The use of HRD dogs is varied and can include crime scenes, burned sites, clandestine and historical burials, natural disasters, water recovery and other situations. Handlers and their dogs pursue different avenues for their training through external workshops, seminars and other training opportunities.

Trailing is a scent-specific discipline that uses the natural hunting abilities of the dog were it still wild and following prey and combines it with the handler’s understanding of scent theory.

Trailing in SAR requires the collection of a hopefully uncontaminated article of the person the dog is meant to search for or something where their scent may be concentrated like a car seat, pillow, door handle. Dogs and their handlers spend countless hours working through different scenarios with articles, volunteer subjects, scent pictures, as well as variations in age and contamination of the trail.

Trailing differs from tracking in that the dog is able to use and take in the surrounding environment and use airscent or the scent on the ground to distinguish and follow one person’s scent and then be able to correctly identify that person. In tracking, the dog has some limitations in where its nose is allowed to be in relation to the exact “track” where a human has walked, and is limited in scenarios where the scent has been blown away, like in a busy urban concrete setting.