Cat and mouse: scientists train rodents to sniff out drugs, explosives

They're small, they're cheap and they have a nose for trouble - and now scientists might have finally developed a cost-efficient system to turn them into drug and explosives detectors.
In a paper in this month's Scientific Reports, Professor Ma Yuanye and his team say they had found a way to train mice to respond swiftly to different odours with 98 per cent accuracy after just four or five days.
Ma, a neurologist with the Chinese Academy of Sciences' Kunming Institute of Zoology, said his team a developed a system using a box about the size of a briefcase.
Five mice were placed in separate compartments in the box and odours were released.
If a mouse touched the alarm sensor in the presence of the compounds, it was rewarded; if it triggered a false alarm, the reward was decreased or even eliminated.
The responses were transmitted wirelessly from the sensors to a computer, which recorded and analysed the results for each mouse.
False alarms were rare, Ma said.