Ratting on wildlife crime: The hero rats busting the smuglers

The Illegal Wildlife Trade (IWT) in flora and fauna is a criminal industry estimated at US $7–23 billion annually. Despite efforts to fight the scourge, detection is challenging, as smugglers often hide illegal items very well.

But there is an unlikely hero in the fight against wildlife crime. Research shows that African giant pouched rats can detect and remember smells of several illegally trafficked wildlife products, including pangolin scales, rhino horn, ivory and endangered hardwood.

Scientists at Tanzania’s APOPO Training and Research Centre trained nine rats to detect targets, even when hidden. “These results provide the foundation to train rats for scent-detection of illegally trafficked wildlife to combat IWT," explained Isabelle Szott, researcher at the Okeanos Foundation.

“The rats also continued to detect the wildlife targets after not encountering them for a long period,” explained Dr Kate Webb, an assistant professor at Duke University. The unique attributes of rats could allow them to complement existing screening technologies. Rats are cheap to train and maintain, can work with multiple handlers, live long, and have a sophisticated sense of smell.

Unlike dogs, handlers can teach the rats to detect multiple target smells in weeks. They can navigate tight spaces and access the contents of sealed shipping containers by sniffing the ventilation systems.

“Existing screening tools are expensive and time intensive and there is an urgent need to increase cargo screening,” Szott explained. In the future, they will determine whether they can deploy rodents at ports and borders to complement existing technologies. Rats could be a powerful tool to protect endangered species and disrupt wildlife crime syndicates.

How they trained the rats

The team taught the rats to hold their noses in a hole with the target scent. They rewarded the rats doing this successfully. The team then exposed the rats to non-target odours, including coffee beans, washing powder, and electric cables. They learned to signal only wildlife-related odours. Eight of the 11 rats could identify four commonly smuggled wildlife species among 146 non-target substances.

This article appeared in the second edition of ThisWildEarth. Read our publications here.

A rat in a chamber training with target scents.

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