Chemical matching dogs

Dogs are commonly used for their superb sense of smell and ability to track and detect small particles across distance (as seen in drug/bomb dogs).

But during the 1900's another ability of the dog was used, it's sense of taste.

Before fingerprint analysis become prevalent method of tying suspects with crime scene objects it was often difficult to prove if a suspect had actually attended a crime scene. What officers did was to get specially trained dog units to move over a crime scene or specifically its objects of interest (knifes, guns etc...) and licking each item to get a taste of any traces left on the items.

Once the dog had had a good licking session, the police would organise a line up (like the visual line ups down today). When a dog was brought into the line up room it would often set the suspects on edge helping them to release sweat this was crucial to the dogs identification process. The dogs had been taught to lick human hands and to get excited when they remembered a taste found at the crime scene.

It had taken years to fully train the dogs to do this sort of work but the results spoke for themselves. Eventually more scientific methods of proving that a suspect had been at the crime scene were introduced and unfortunately the dog licking was phased out. Dogs still continue to help police with their noses and their attacking ability.