Keen-nosed rats could save pangolins from extinction

The pangolin, an endangered anteater that is one of the world’s most poached animals, could use a hero. Fortunately, a big rat is training for the job.

Actually, 11 African giant pouched rats are. At a research center in central Tanzania, the 2-foot-long rodents are learning to detect the smell of pangolins’ armor-like scales, which are smuggled to Asia for use in sham traditional remedies. If the rats succeed, they and their twitching noses could eventually deploy to ports, national park borders and even highways to sniff out illegal shipments and help bust traffickers.

The species already has a strong track record in detection. The Belgian organization APOPO has been training their “heroRATS” to find land mines for 20 years, and it says the animals have helped clear more than 100,000 mines from former war zones. In the past decade, the rats have been used to detect tuberculosis, a highly infectious disease that public health facilities often miss. They can screen 100 mucus samples in 20 minutes — a job that would take clinics four days — and APOPO says they’ve boosted TB detection by 40 percent at the clinics they work with.

Now, with funding from U.S. Fish and Wildlife Services, the organization has begun training the keen-nosed rodents to help another animal — one at risk of going extinct. Demand for pangolins, reclusive animals that look like walking pine cones, is so great that some conservation groups say their populations in Africa and Asia have dropped 90 percent in the last decade. Smugglers often pack their dried scales with other pungent products, like coffee and wax, that can throw off detection dogs.

The rats, which APOPO breeds at its headquarters in the city of Morogoro, are introduced to people when they’re four weeks old. They’re then trained for months using basic Pavlovian conditioning: The rat hears a click and gets a treat — avocado or banana — when it sniffs a target scent. Eventually, various scents are placed in holes, and the rodent gets the food reward when it stops and lingers over the target.

Using rats to ferret out pangolins could have advantages over other methods, said Cynthia Fast, APOPO’s head of training and behavioral research. X-rays are used at some ports, but they’re expensive and can bottleneck operations. Dogs sometimes struggle in withering heat and can contract some fly-borne diseases, but not the giant rats, Fast said. And while the rats can be very affectionate, they don’t bond with individual handlers, making their training and deployment more seamless than that of detection dogs.

“They bond in general with people. If you come and visit our center, you see them following certain people around, not even on a leash. It’s the cutest thing,” Fast said. “But they do it indiscriminately.”

The trainee rats have all been named after celebrity wildlife conservationists — one is Fossey (for Dian, the gorilla researcher); another is Betty White, after the actress and animal activist.

Fast said the pangolin-sniffing rats won’t be put to work for another two to five years.