Giant rats trained to sniff out smuggled ivory and rhino horn

Cheap, easy to train and with a long lifespan – these rodents could replace sniffer dogs

A spaniel’s nose has long been used to catch smugglers and contraband, but scientists have now found an unusual replacement for the traditional sniffer dog.
African giant pouched rats have been trained by scientists to recognise the scent of illegal animal products such as rhino horn and elephant ivory.
Demand for these products is decimating population numbers of at-risk species as illegal poaching sees hunters kill the animals and harvest parts of their bodies for sale on the black market.
Many parts of Asia have high demand for ivory, horns and scales where they fetch enormous sums of money before being used in traditional medicine formulas.
Authorities are trying to stop the trade to save many species from being hunted to extinction and scientists have turned to giant rodents the size of rabbits equipped with a jacket and leash to help.
The rat species has previously been trained to identify signs of tuberculosis and explosives and now 11 of them – Kirsty, Marty, Attenborough, Irwin, Betty, Teddy, Ivory, Ebony, Desmond, Thoreau, and Fossey – were trained to spot wildlife trafficking.
Rats, the scientists say, are ideal sniffer animals and have already been trained to identify the aroma of landmines and tuberculosis.
They are cheap, easy to train, can work with a range of humans, have a long lifespan (the African giant pouched rat can live up to nine years) and have a good sense of smell.
Their size and nimbleness also allows them to access nooks and crannies other detection methods would not be able to reach, scientists say.
The rats were taught to recognise the smells of prohibited products and rewarded with a food treat in the form of flavoured food pellets. They were then trained to only signal when the smell was present and not when they encountered other powerful scents, such as coffee and laundry detergent.
Analysis showed that participant animals were able to remember the smells after several months and the rodents had cognitive skills on par with dogs.
By the end of the study seven of the original 11 rats were able to accurately determine when they were close to rhino horn, elephant ivory, pangolin scales and a threatened African hardwood.
“The rats also continued to detect the wildlife targets after not encountering that species for a long period,” said study first co-author Dr Kate Webb, an assistant professor at Duke University.
“Rats are cost-efficient scent detection tools,” added Dr Isabelle Szott, a researcher at the Okeanos Foundation, and first co-author of the study published in Frontiers in Conservation Science.
“They can easily access tight spaces like cargo in packed shipping containers or be lifted up high to screen the ventilation systems of sealed containers.”
The scientists now want to train more rats and deploy them at ports and border crossings to crack down on the wildlife trade.
“Wildlife smuggling is often conducted by individuals engaged in other illegal activities, including human, drug, and arms trafficking,” said Dr Webb.
“Therefore, deploying rats to combat wildlife trafficking may assist with the global fight against networks that exploit humans and nature.”