In many formerly warring regions, landmines remain scattered underneath the countryside. And finding them is no easy task. The most common solutions, like bomb-sniffing dogs and metal detectors, are costly and time-consuming. Now, a nonprofit organization called APOPO thinks that there’s a better solution: Bomb-sniffing rats.
"The idea was very strange," APOPO Cambodia’s operations coordinator Theap Bunthourn tells Michael Sullivan for NPR. "Cambodian people kill rats. [They] don't like rats. But they're cost-efficient, they're easy to transport, they're easy to train, and they don't set off the mines because they're too light."
These aren’t your typical subway rat: The African giant pouched rat is about the size of a cat, writes Rachel A. Becker for National Geographic. While their eyesight isn’t great, they have an impeccable sense of smell and are able to identify and detect the smell of TNT from amounts as small as 29 grams, Sullivan reports.
The rats are also cheaper and easier to train and handle than dogs, which are commonly used to clear Cambodian minefields. While dogs can only work with the handler they bond with, the rats will happily hunt mines for anyone holding their leash, as long as they get a tasty reward whenever they find a mine.
When fully trained, a rat can search over 2,000 square feet in 20 minutes. It could take a human with a metal detector as much as four days to scour the same area, APOPO training manager Abdullah Ramadhan tells Becker.
While training still costs about $6,500 per rat, the little explosives experts have helped find about 13,200 mines in Tanzania, Mozambique, Angola and Cambodia over the last 20 years.
The giant rats are trained to hunt mines from infancy, learning to distinguish the smell of TNT from other industrial smells, like motor oil and battery acid. When a rat finds a landmine, they stop and scratch at the ground. A person then double-checks the site with a metal detector and if a mine is found, it is safely detonated.
The rats undergo rigorous testing before they are allowed in the field, "Some rats do fail," Tim Edwards, APOPO’s head of training, tells Sam Jones for The Guardian. "We’re doing dangerous work and we don’t want to put rats into the field that can’t do it."
Mines aren’t the only thing APOPO is training rats to hunt. The next target is identifying diseases like tuberculosis and cancer from saliva. But while there are some skeptics who doubt the rats’ abilities, Edwards still has faith in the giant rat’s powerful nose.
"There’s so much potential," Edwards tells Jones. "It’s just a matter of finding the time and the resources to investigate it."