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.
The computer drew its conclusions from the responses of all five mice, rather than any one individual, to increase accuracy.
The whole set-up cost less than 100 yuan (HK$126), according to the scientist.
"It is a fully automated process. Human intervention in training will become history," Ma said.
Scientists have spent decades looking for ways to turn small animals with sharp noses such as rodents and insects into bomb detectors but training mice is time consuming.
Yunnan province, where Ma's institute is based, has a special demand for detectors. The province borders several countries in Southeast Asia and the region is a hub for drug traffickers and terrorists.
China's customs and border patrols now mainly rely on dogs and machines to detect explosives and narcotics but dogs also take a lot of time to train and machines are bulky and expensive to use.
That could change with the newly developed mouse-training system.
"It can be used indoors or outdoors, almost any areas in need of chemical detection, especially places unsuitable for dogs or impossible for big machines," he said.
"We built the system with extra mobility and reliability so it could be used in any place, at any time, by anyone."