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Smell a rat at a crime scene? It's probably the latest police recruit

Dutch police have pioneered a whole new way to rat out criminals by hiring some of the keenest noses in the underworld.

Five brown rats are due to go into active police service next year.Five "sniffer rats" have spent two years at the animal training centre in Rotterdam learning to distinguish a range of scents including blood, drugs and explosives, and communicate with their handlers.

The brown rats are due to go into active service next year, operating under the names Poirot, Magnum, Derrick (a German TV detective popular in the Netherlands) and Jansen & Janssen (the Dutch names for the bowler-hatted detectives in Tintin).


Their sensitive noses – rats have 1,493 receptor genes compared to 1,093 for dogs and 650 in humans – and their small size make them ideally suited for the task, trainer Monique Hamerslag told De Volkskrant.

The trainers at the Levende Have centre have set up a training room for the rats, where they learn to identify suspicious substances kept in jars and hamster wheels and notify their handlers by making a clicking noise.

A radio is left playing permanently in the room to allow the rats to acclimatise to the background noise of a bustling city. When not training in their cages the rats are left to run free.

A sign on the door advises visitors not to carry guns or traces of explosives and adds the message: “Please do not tread on the rats.”

The Netherlands will be the first country in the world to use trained rats in civilian police investigations.

The idea came initially from Africa and Asia, where hamster rats are used to clear fields of landmines. As well as having a keener sense of smell they have the advantage of being less likely to set off the mines than heavier sniffer dogs.

“I thought, if rats can trace mines, the police should be able to use them,” said Hamerslag.

Police plan to deploy the rats initially at crime scenes such as shootings, where they are able to detect gunshot residue on a suspect’s body or clothing.

The rodents can sniff out traces of explosives on somebody’s clothes within seconds, compared to the hour or two it takes to analyse material in a laboratory.

Mark Wiebes, a police innovation manager, told NOS: “We place a type of cloth over the hands of someone who we think may have fired a shot, and then we let the rat sniff the cloth.”

The rats will not take the place of laboratory analysis, but police hope they will speed up the process of identifying which suspects need to be investigated further.

Source: De Volkskrant: Wereldprimeur: politieratten gaan helpen verdachten op te sporen