Sniffer dogs that are trained with so-called "pseudo-explosives" cannot reliably detect real explosives, according to a new study.
Genuine explosive materials are traditionally used to train dogs to detect explosives and to test their performance later on.
However, challenges arising from the acquisition, storage, handling and transport of explosives have motivated the development of "pseudo-explosive" or "pseudo-scent" training aids.
These products attempt to mimic the odour of real explosives, yet remain non-hazardous. The intent is that a canine trained on a pseudo-explosive would be able to detect its real-life analog, and vice versa.
Researchers at the Indiana University-Purdue University Indianapolis (IUPUI) tested how well a group of 17 dogs were able to locate three types of explosives and their pseudo-versions: single-base smokeless powder, 2,4,6-trinitrotoluene (commonly known as TNT), and a RDX-based plastic explosive (Composition C-4).
The dogs trained on simulated explosives could sniff out the genuine article only 14 per cent of the time.
Similarly, dogs trained on real explosives responded to pseudo-explosives only 16 per cent of the time. In fact, on the whole, the animals only had a nose for the materials upon which they were trained.
For example, dogs trained on real explosives were able to locate them 81 per cent of the time. Dogs trained with the pseudo-explosive versions had a very similar success rate of 88 per cent.
The failure of the dogs to be "cross-trained" does not mean that the pseudo-explosives contain the wrong ingredients.
Researchers determined via chemical analysis that the volatile compounds given off by pseudo-explosives consist of various solvents, additives and common impurities that are present in authentic explosives.
"The exceptional sensitivity of the canine's nose and the impressionable nature of its temperament have made canines a valuable tool when it comes to sweeping for hidden bombs and explosives," researchers said.
"However, dogs trained on pseudo-explosives performed poorly at detecting all but the pseudo-explosives they were trained on.
"Similarly, dogs trained on actual explosives performed poorly at detecting all but the actual explosives on which they were trained," they said.
