Dutch police recruit rodents to rat on criminals

‘Employed’ by the Dutch police innovation centre, their ‘boss’, the police officer in charge of the project, Monique Hamerslag, said she got the idea from the way rats are used in Tanzania to sniff out landmines.

Rats can learn to sniff out any odour, from drugs to explosives. In the future they could even sniff out blood or money to help to move along investigations.

Costing much less than dogs both to keep and to train, rats need only 10 to 15 days to learn to distinguish a certain smell. Tea strainers containing different substances are attached to the cages and when the rat detectives identifies gunpowder, they are rewarded with a ‘click’ sound and a sunflower seed.

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Perhaps surprisingly, given rats’ fearsome reputation, the main disadvantage to using them in investigations is their shyness.

”It’s best to bring the smell to the rats and not the other way round,” Ms Hamerslag told AFP. “That means we have to take samples and bring them to where the rats live.”
— morse, f., (2013) 'rats to sniff out criminals', http://www.independent.co.uk/news/dutch-police-recruit-rats-to-sniff-out-criminals-8851198.html
As strange as rodent detectives may seem, they aren’t the only unconventional animals used by law enforcement. The American Defense Advanced Research Laboratory (Darpa) has been training bees to sniff out explosives since the late 90s. The same methods used to seek out molecular hints of pollen can be, in theory, exploited to detect small particles of explosives.

Further east, five-year-old Santisuk — a macaque monkey — joined the police force in Thailand to improve community relations. Dressed in his bespoke uniform, with a yellow badge proclaiming “Monkey Police”, Santisuk’s duties include checkpoint control and helping residents pick up coconuts.

And finally Officer Lemon was employed by the Yoro police station in Kyoto, Japan, making him Japan’s first police cat. Lemon helps to keep Japanese officers happy and is frequently called out to situations that involve suspicious phone calls, as he is said to have a calming effect on the victims.
— Tufnell, N. (2013) Dutch poice recruit rat detectives to sniff out crime, Wired UK