Ratting on criminals is an essential mechanism in the fight against crime, and this is normally done by whistleblowers and finks (informers). The rats referred to here are the four-legged variety found in research labs. They are quick learners and have sensitive noses, and hence can be trained for the tedious and dangerous work involved in identifying drugs and explosives. In Nature Online, in 2002, it was reported that the University of Baltimore was using rats, fitted with motion sensors, to detect cocaine.
The rats were trained to rear up on their hind legs when they detected cocaine. This action was transmitted to a computer which identified their location and hence that of the illicit drugs. The use of rats in the fight against drugs and crime is growing. In Mozambique, giant “hero rats” were successfully used to detect more than 2,000 land mines, nearly 1,000 bombs and thousands of small arms and ammunition.
They cleared over six million square metres (about two and one third square miles) of land. Countries investing in their use include USA, Israel, Netherlands and Colombia. So why rats? As pointed out earlier they are quick learners and have superior sniffing capabilities. They can be trained to detect drugs, explosives, gunshot residue, blood and other substances.