Rats take over the illegal wildlife trade by sniffing out rhinoceros tusks, horns

Wildlife crime is among the top illegal industries globally, ranking fourth behind arms, drug and human trafficking. It is estimated to be worth up to $23 billion a year, with pangolin scales, elephant tusks and rhino horns being the most sought-after items on the black market.

But its cost is far greater than money, as pushing these species to the brink of extinction, destroying entire ecosystems and causing untold suffering to animals are just some of the far-reaching consequences that threaten our planet’s biodiversity.

The Wildlife Conservation Society reports that around 35,000 elephants are illegal poaching every year. This means that an elephant is killed every 15 minutes for its ivory. Meanwhile, 499 rhinoceros were lost for illegal hunting in South Africa last year, scoring 51% grow compared to 2022.

To deal with persistent ones threat of poaching, scientists have now turned to Giant African pouched rats for help, according to a study published in Frontiers in Conservation Science.

The research, led by Isabelle Szott, Ph.Da researcher at the Okeanos Foundation and one of the study’s co-authors, shows how these nocturnal animals can detect the scent of animals and plants listed as threatened or endangered. Pangolin scales, elephant ivory, rhino horn and African black wood are just the beginning of what these rats can learn to identify.

Giant African rats rely on their sense of smell and hearing

Native to sub-Saharan Africa, Giant African pouched rats (Cricetomys gambianus), also known as Gambian rats, are the largest rat species. They weigh up to 9 kilograms and have very poor eyesight. To compensate, however, they must rely heavily on their senses of smell and hearing.

This, according to Kate Webb, Ph.Dassistant professor of psychiatry and behavioral sciences at Duke University and first co-author of the study, is exactly what led the research team to consider these rats in detecting poaching materials. “Working with the Endangered Wildlife Trust (EWT) in South Africa, we began investigating the potential of detection rats to combat the illegal wildlife trade,” said Webb. Interesting Engineering (IE) in an interview. “We believe that tackling the illegal wildlife trade requires innovative approaches while remaining cost-effective, scalable and flexible.”

Webb, who is also the US scientific advisor to APOPO, a non-profit organization based in Tanzania, says the organization has been training giant rats for scent-related tasks, including detecting mines and tuberculosis in biospecimens, for 25 years. “We thought rats had a special set of skills that could make them valuable members of the fight against the illegal wildlife trade,” she adds. “For example, one of the key advantages of rats is that they are easily transferable between trainers.”

Neuroscientist explains how adaptable rats are when it comes to deployment strategies. “Rats are light and small enough that they can be lifted to cover the vents located at the top of the shipping containers.”

The training process

Named Kirsty, Marthy, Attenborough, Irwin, Betty, Teddy, Ivory, Ebony, Desmond, Thoreau and Fossey, the rats went through various stages of training. “You might recognize some of the rat names,” says Webb.

“Many of them were named after conversationalists and advocates against wildlife trafficking, for example we have David Attenborough, Steve Irwin, Dian Fossey, Betty White, Henry David Thoreau and Teddy Roosevelt!”

Webb explains how they were all trained using positive reinforcement techniques.

“During cued training, rats learn to perform a specific behavior (here in the form of sticking their nose in a hole for a set period of time) while being presented with a target odor, such as pangolin scales,” adds the neurologist. “When the rats perform the so-called nose poke correctly, they are rewarded with food.”

The rats then underwent discrimination training where they were exposed to non-target odors such as electrical wires, coffee beans and washing powder.

These are often used to hide the scent of wildlife in real traffic operations. “Here, a nose poke into a hole containing a so-called non-target does not result in a food reward, while nose pokes at wild targets continue to be rewarded,” says Webb. “During the discrimination stage, rats learn to signal only the odors of wildlife targets while ignoring non-targets.”

Teaching rats to detect wildlife requires advanced training, as traffickers are constantly devising new methods to hide their contraband. To enhance the smell memory of rats, scientists exposed them to a wide range of items. Once their retention training was complete, the rats were presented with odors they hadn’t smelled again in five and eight months.

Remarkably, despite the long gap, the rats demonstrated perfect retention scores, suggesting that their cognitive retention abilities are similar to those of dogs. Furthermore, eight of them successfully identified four commonly trafficked wildlife species from a list of 146 non-target substances.

“These rats performed exceptionally well when faced with this challenge, detecting wildlife targets and ignoring nearly 150 non-target items, including biologically relevant odors such as the odor of another rat or food tasty like peanuts,” says Webb.

“I wasn’t necessarily surprised that it could work so well, but our findings just underscored what incredible olfactory abilities these rats have!”

When asked about the welfare and ethical treatment of the rats, Webb ensures that each rat is well cared for, receiving a nutritious diet, regular exercise, mental stimulation, enrichment and loving attention from their experts.

“Each of our rats is considered an extremely valuable asset, making animal welfare a priority,” explains Webb. “If a rat decides to stop working, or if its performance has declined, or if it suffers from age-related health problems, it is retired.”

Practical uses and additional steps

The next phase, Webb explains, involves training the rats to work in the ports. They will be fitted with specially designed vests, each with a small ball attached.

When the rats use their front paws to shoot the ball, the vest will emit a sound, alerting their handlers that a target has been detected. “We see rats as an additional and complementary tool to combat the illegal wildlife trade,” says Webb. “They are cost-effective, which makes them an attractive option, especially in developing countries.”

The neuroscientist points out that rats could also be employed to control areas in shipping ports where dogs cannot reach, such as container vents. “The more pressure we can put on traffic networks, the higher the operational costs for them,” adds Webb. “Developing new and innovative methods to combat illegal wildlife trade signals to poachers and smugglers that we are invested and resolute in our fight against all forms of illicit trade.”

After several successful tests in port environments, the researchers are confident that further operations will require the support of each country not only to import the rats, but also to implement them and recognize their findings as evidence.

As for whether African pouched rats could be used for other detection capabilities, such as human trafficking and drug trafficking, Webb is confident they can be trained to identify a wide range of substances.

“We believe rats have the potential to support more efficient and cost-effective screening and serve as an additional deterrent,” Webb concludes. “Wildlife smuggling is often carried out by people involved in other illegal activities, including human, drug and arms trafficking, and therefore deploying rats to combat wildlife trafficking can help in the global fight against networks that exploit people and wildlife .”