Dog noses beat human eyes

Monday, August 9, 2010

In spite of the distraction posed by a ground squirrel, sniffer dogs' noses proved better than human eyes when it comes to identifying spotted knapweed, says a scientific journal devoted to invasive plant species.

Invasive Plant Species and Management, published by the Weed Science Society of America, cites a study conducted in Montana that pitted trained detection dogs against human eyes. Dogs and humans were equally good at spotting medium and large sized plants. Dogs were better at finding the small ones. Humans found plants 59 per cent of the time, while the dogs' success rate was 81 per cent. "Visual surveys for these plants often reflect only adult life stages, whereas non-flowering plants and inconspicuous life stages can often be overlooked under intense searches."

The study said detection dogs are trained to search for specific odours and have been used to find buried land mines, human remains, and desert tortoises (believe it or not). They key on volatile organic compounds with distinctive odours.

The study's authors say invasive species "have devastating effects on ecosystems and biodiversity that early intervention can prevent." Species like knapweed are hard to contain or eradicate because it is hard to detect low density populations and individual plants.

The German shepherd distracted by the ground squirrel was the least accurate of the three dogs tested the study notes. "Search accuracy might also be improved and detection bias reduced by selecting slow-searching dogs with the ability to concentrate in field settings," the study notes.

Predictably, the researchers called for more research. BF