In the fight against the illegal trade in elephant ivory and rhino horns, these cute rodents must now make a difference


You may have thought that dogs in particular are equipped with an excellent sense of smell. But rats also appear to be an unexpected ally in detecting smuggled wildlife goods.

There are people who believe that certain products from wild animals have healing properties, can increase their social status, or simply make a lot of money. Examples include elephant tusks and rhino horns. Fortunately, much is being done to detect and intercept such ‘wildlife products’. For example, dogs can detect specific odors, such as ivory, and thus find illegally traded goods. But our four-legged friends receive help from an unexpected source. Because researchers have now also trained rats to perform the same task.

Sense of smell
We have known for some time that some animals are equipped with more than an excellent sense of smell. It is not without reason that we rely on the muzzles of dogs to detect drugs, explosives and more recently even… the coronavirus. But some rodents also appear to have a particularly good sense of smell. For example, detecting explosives is not just for dogs, the Gambia hamster rat also seems to be good at this. Moreover, in the past, researchers have also taught this rat to detect the bacteria that causes tuberculosis. Now, a team of researchers has trained the Gambia hamster rat to detect the scent of pangolin scales, elephant ivory, rhino horns and African blackwood. These animals and plants are endangered and at high risk of extinction.

More checks
Current detection methods for such wildlife assets are often expensive and time-consuming. That is why there is currently an urgent need for more controls on freight. “We see the Gambia hamster rat as a valuable addition to the fight against the illegal wildlife trade,” researcher Isabelle Szott tells Scientias.nl. “Our study shows that we can train these rats to detect illegally traded wildlife goods, even if they are hidden among other materials.”

De training
In the study, a number of rats – Kirsty, Marty, Attenborough, Irwin, Betty, Teddy, Ivory, Ebony, Desmond, Thoreau and Fossey; some of which are named after conservationists and fighters against wildlife trafficking – different training steps. For example, the rats learned to hold their noses for several seconds in a hole in which the target odor was applied. If they performed this ‘nose poke’ correctly, they received a tasty reward.

This rat receives a reward in recognition of completing its task well. Image: APOPO

Washing powder and coffee beans
In the next phase, the rats were introduced to non-target odors. These included electrical cables, coffee beans and washing powder – items often used to hide the scent of wildlife. “During this phase, the rats learn to identify only the odors of the wild animals, while they have to ignore the other odors,” Szott explains. The rats were also trained to remember odors. At the end of this training phase, they were again confronted with odors that they had not smelled for five and eight months respectively. Despite the long time that had passed, the rats were still able to detect the target odors just fine. This indicates that their ability to remember information is comparable to that of dogs. At the end of the training, eight rats were able to identify four commonly smuggled wildlife goods among as many as 146 other substances.

Benefits of rats
Why do researchers now want to use Gambia hamster rats in the fight against illegal trade in wildlife goods? “They are cost-effective, which makes them an interesting choice, especially in developing countries,” Szott explains when asked. “In addition, rats have specific skills that can complement existing detection methods such as dogs and X-ray machines. A major advantage of the rats is that they can easily change trainers. Moreover, they are very versatile in their use; rats are light and small enough to be lifted up to check the vents at the top of shipping containers.”

Impressive
Szott is very impressed with the ability of these rats to intercept illegal wildlife goods. “Although the rats have proven themselves many times over the years, it remains impressive to see how quickly they learn new odors, how accurately and quickly they work and what they can do,” she says.

Vest
The next step is to find ways for the rats to work in ports where smuggled wildlife goods are traded. For this purpose, the rats are fitted with special vests. With their front legs they can pull a small ball attached to their chest that makes a squeak. In this way, the rats can warn their handlers when they have found a target odor.

This rat wears a vest with a ball attached to it that emits a beep. Image: APOPO

Other animals
In addition, the researchers plan to train the rats to recognize even more target odors. “We are convinced that the rats can also learn to detect other odors when necessary,” Szott argues. “We want to continue working with port authorities to identify more wild animal species, such as turtles or lion products. The more pressure we put on smuggling networks, the more expensive it becomes for them to remain active.”

Smuggling of wildlife products, such as ivory and rhino horns, often goes hand in hand with other illegal activities, including human trafficking, drug trafficking and arms trafficking. Using rats against these smuggling practices can therefore help in the global approach to criminal networks that exploit both people and nature. The researchers will therefore continue their important work and will continue to train the rats. “We are already working with port authorities, customs and police,” said Szott. “There is really a lot of interest in the rats. For example, we have already received requests from ports in Singapore and France. However, it will require the support of every country to import our rats, deploy them and accept their findings as evidence in court.”