Giant rats could help detect illegal wildlife trade
- African giant pouched rats have a keen sense of smell. They’ve been used in the past to sniff out explosives and more.
- Now giant rats are learning to sniff out illegally trafficked wildlife, such as pangolin scales, elephant tusks, rhino horn and rare wood.
- Smugglers who deal in illegal wildlife are also often involved in other illegal activities, including human, drug and arms trafficking. So the rats could assist with the global fight against networks that exploit humans and nature.
Frontiers published this original article on October 29, 2024. Edits by EarthSky.
Giant rats could help detect illegal wildlife trade
Pangolin scales, elephant tusks, rhino horn and a rare wood are preferred objects in the illegal wildlife trade. African giant pouched rats, with their keen sense of smell, however, could soon help to intercept this trade. Researchers showed the rats can successfully sniff out parts of endangered animals and remember the scent months after training. Employing them in the field could increase pressure on wildlife smugglers and add a flexibly deployable tool to screen cargo, the researchers said.
In the past, African giant pouched rats have learned to detect explosives and the tuberculosis-causing pathogen. Now, a team of researchers have trained these rats to pick up the scent of pangolin scales, elephant ivory, rhino horn and African blackwood. These animals and plants are threatened and at high danger of extinction.
Isabelle Szott, a researcher at the Okeanos Foundation, is the first co-author of the study published in Frontiers in Conservation Science. Szott said:
Our study shows that we can train African giant pouched rats to detect illegally trafficked wildlife, even when it has been concealed among other substances.
First co-author Kate Webb, an assistant professor at Duke University, added:
The rats also continued to detect the wildlife targets after not encountering that species for a long period.
The researchers conducted their study at APOPO, a Tanzania-based, non-profit organization that provides a low-tech, cost-efficient solutions to pressing humanitarian challenges.
Ratting out wildlife trafficking
The rats – Kirsty, Marty, Attenborough, Irwin, Betty, Teddy, Ivory, Ebony, Desmond, Thoreau and Fossey, some of them named after conservationists and advocates against wildlife trafficking – underwent several training stages. During indication training, the rats learned to hold their noses for several seconds in a hole where the target was. When they correctly performed this ‘nose poke,’ they received a reward with flavored rodent pellets.
In the next step, researchers introduced the rats to non-target odors. These included electric cables, coffee beans and washing powder. Smugglers frequently use these objects to mask the scent of wildlife in real-life trafficking operations. Szott said:
During the discrimination stage, rats learn to only signal the odors of the wildlife targets, while ignoring non-targets.
Researchers also trained the rats to remember smells. At the end of their retention training, they were reintroduced to scents they’d not encountered for five and eight months, respectively. Despite months of non-exposure, the rats showed perfect retention scores, suggesting that their cognitive retention performance resembles that of dogs.
By the end of the training, eight rats were able to identify four commonly smuggled wildlife species among 146 non-target substances.
Good giant rats!
Rats in action
Szott explained:
Existing screening tools are expensive and time intensive, and there is an urgent need to increase cargo screening. APOPO’s rats are cost-efficient scent detection tools. 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 next step, the scientists said, is to develop ways for the rats to work within ports through which smugglers trafficked wildlife. For this purpose, researchers will outfit the rats with custom-made vests. With their front paws, they will be able to pull a small ball attached at the chest of their vest, which emits a beeping sound. This way rats will be able to alert their handlers when they detect a target. Webb said:
The vests are a great example of developing hardware that could be useful across different settings and tasks, including at a shipping port to detect smuggled wildlife.
This proof-of-principle study demonstrates that rats can successfully identify trafficked wildlife. This does not mean that it comes without limitations, the researchers said. For example, they conducted the study in a controlled environment, which is not reflective of the settings in which wildlife is commonly trafficked or screened by scent-detection animals. To deploy rats for this task, the researchers said they would need to develop new methods.
Webb concluded:
Wildlife smuggling is often conducted by individuals engaged in other illegal activities, including human, drug and arms trafficking. Therefore, deploying rats to combat wildlife trafficking may assist with the global fight against networks that exploit humans and nature.
Giant rats learning their roles
Bottom line: Researchers are training giant rats to sniff out illegal wildlife samples in an effort to curb the trade of these materials.
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