Giant three-pound rats, trained to detect illegal poaching

African giant in the pocket rats (Cricetomys gambianus) could be the next line of defense in the illegal wildlife trade. A team of researchers trained these three-pound rats pick up the scent by elephant ivoryrhino horn, pangolin scales, and a small tree called African blackwood. All of these animals and plants are listed as endangered or at high risk of extinction and are traded illegally. The findings are detailed in a proof-of-principle study published Oct. 30 in the journal Frontiers in conservation science.

“Our research shows that we can train African giant possums to detect illegally traded wildlife, even if they are hidden among other substances,” study co-author and Okeanos Foundation behavioral scientist Isabelle Szott. said in a statement.

Sniffing things out

Previously, African giant possums were trained for this detect explosives and even the pathogen that causes tuberculosis. This new research to test their ability to detect wild animal scents was conducted on APOPO. The Tanzania-based nonprofit aims to protect both people and animals with trained rats and other scent-detecting animals.

It included 11 rats–Kirsty, Marty, Attenborough, Irwin, Betty, Teddy, Ivory, Ebony, Desmond, Thoreau and Fossey. They all underwent various phases of scent training. They learned this during the indication training hold their nose for a few seconds while in a hole where the target odor was placed. If the rat correctly performed what the team called a “nose poke,” they were rewarded with flavored rodent pellets.

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Next were the rats introduced to some non-target odors. This included coffee beanselectric cables and washing powder. Wildlife traders often use these items to mask the scent of wildlife.

“During the discrimination phase, rats learn to identify only the odors of the wild animal targets, while ignoring non-targets,” Szott said.

So were the rats trained to remember smells. At the end of this training, they were reintroduced to smells they had not encountered for five and eight months. Even with such a long period of non-exposure, they showed high retention scores. Their cognitive retention performance is potentially as strong as one dog.

By the end of the training, eight rats were able to identify four commonly trafficked species among 146 non-target substances.

“Existing screening tools are expensive and time-consuming and there is an urgent need for more cargo screening,” Szott said. “APOPO’s rats are cost-efficient odor detection tools. They easily access tight spaces, such as cargo in packed shipping containers, or can be lifted high to shield the ventilation systems of sealed containers.”

Getting rats to work

According to the teama good next step is to develop ways for the rats to work in the ports where smuggled wildlife is traded. These include the ports of Mombasa, Kenya, and Dar es Salaam and Zanzibar in Tanzania, This is evident from data from the United Nations Office on Drugs and Crime.

To do this, the rats would be equipped with custom-made vests. They can attach a ball to the chest of the vest with their front paws, which makes a squeaking sound. This way, the trained rats can let their handlers know when they detect a target.

With their forelimbs they can pull a small ball onto the chest of their vest, which makes a squeaking sound. In this way, rats can alert their handlers when they detect a target.

“The vests are a great example of developing hardware that could be useful in a variety of environments and tasks, including in a shipping port to detect smuggled wildlife,” study co-author and Duke University neuroscientist Kate Webb. said in a statement.

(Related: How science became dependent on the humble laboratory rat.)

Although the rats in the study were able to successfully identify the odors associated with trafficked wildlife, there are still some some limitations. The research was conducted in a controlled environment and therefore does not reflect the situation in the real world, where wildlife is often traded or screened by scent-detecting animals. According to the team, new methods must be developed to use these rats.

“Wildlife smuggling is often carried out by individuals involved in other illegal activities, including human, drug and weapons trafficking,” Webb said. “That is why using rats to combat wildlife trafficking can contribute to the global fight against networks that exploit people and nature.”