The Boom Ground Rats: Are HeroRATs The Key to Landmine Detection?

Clearing a field of active landmines is a delicate operation. It requires intelligence, patience and precision.

It’s the perfect job for a rat.

We take a dim view of rats, and for understandable reasons. The most celebrated rat of recent memory was a pizza thief; the most notorious rats in history helped spread a plague that nearly wiped out humanity. But rats are too smart and adaptable to be dismissed as symbols of extreme urban decay or disease vectors. Scientists are putting the unique physiology and abilities of rats to work saving lives by detecting landmines.

Worldwide, landmines killed around 1,600 people last year alone. Most landmine deaths occur in developing countries. At present, 60 countries are threatened by landmines, including large numbers in Africa and Asia. Volatile explosives are spread throughout farmland in countries with primarily agricultural economies. In Cambodia, where landmine death and injury rates are highest, people are forced to work in contaminated fields to survive.

“You’re walking along a main road where there are people walking and driving in cars, but you’re not allowed to step off that main road,” says James Pursey, head of communications for APOPO, a nonprofit organization that trains rats to detect landmines. “You can go about two meters outside the road, otherwise you’re in an area that could potentially have landmines.”

That makes the need to clear landmines all the more urgent. Unfortunately, many government funds allocated for demining have shrunk over the years. It’s a problem that’s inspired radical solutions—from enormous high tech tumbleweed balls to detection animals like dogs and elephants—to accompany traditional human and machine methods of detection.

Rats have several advantages over other landmine finding methods. They can clear 200 square yards of landmine contaminated land in half an hour; an amount of land that would require professional deminers with metal detectors multiple days to traverse.

“If you’re a deminer and your metal detector goes off, you’re going to carefully investigate what’s causing that, even if it’s scrap metal,” Pursey explains.

The rats, meanwhile, ignore common scrap metal as they scurry over the contaminated land and only stop when they smell explosives or TNT. The rodents scratch the ground where they detect the scent, allowing deminers to quickly cover concentrated areas.

And that’s not to mention their most obvious advantage: when rats scurry over a landmine, there’s no explosion.

“The rats are too light to set off the mines, so it’s much safer,” Pursey says. “We have not yet lost a rat to a landmine accident.”

APOPO has trained landmine rats—better known as HeroRATs—for almost two decades. The idea first came to Dutch social entrepreneur Bart Weetjens after watching a documentary about the global landmine problem. Weetjens was already an expert in training rodents and was well aware of their capabilities. He brought the idea back to advisors at the University of Antwerp in Belgium, where the novelty struck instant interest.

“I think they were interested to see if something like that could be done rather than fully believing it could,” Pursey says. “But they also couldn’t really see a reason not to try it.”

Despite the obvious benefits, there was still the issue of overcoming common perceptions of rats. APOPO trains African giant-pouched rats that roughly the size of a cat. Dirty them up and throw them on subway tracks, and they’re the kind of rodents that haunt New Yorkers’ dreams. Even those that eventually come to love them are taken aback at first.

“Lots of our trainers are scared at the beginning. They think the rats are dirty, they think they’re pests,” Pursey says. “But it doesn’t take them long to understand what they can do.”

“I had always thought of them as destructive animals,” says APOPO trainer Pendo Msegu. Born and raised in Morogoro, Tanzania, where the rats often steal garbage and eat crops, she loved animals but took a dim view of the rats.

“I wasn’t a big fan,” Msegu says.

When she heard that APOPO was hiring, she applied for the job. At the interview, the organization’s CEO, Christophe Cox entered holding one of the HeroRATs.

“I was a bit shocked at first,” Msegu says, “but when I saw how he was holding the rat and how the rat was reacting to him, completely calm and gentle, that changed my mind and told me it was okay.”

Over the next several weeks, Msegu noticed how well the rats responded to clicker response training, a method regularly used for dog obedience. The rats learn to associate the sound of a click with a food reward.

It doesn’t stay so simple for long, however. The rats are smart, and particularly adept at performing repetitive tasks. In the quest for food, corners are cut.

“It’s kind of like a constant game to see if we can overcome their shortcuts,” he says. “It works well, and the rats are happy to do it.”

After the nine month training period, the rats are tested based on the International Mine Action Standards (IMAS). When they’re delivered to the country they’re working in, the rats are then retested by the authority oversees mine action in that nation.

Getting the rats into a given country can be difficult due to the bureaucracy and various government agreements necessary to do so. APOPO has operations in Cambodia, Zimbabwe, Angola, and Mozambique, the latter of which has been perhaps its most successful. Over a decade, APOPO’s HeroRATs helped clear more than 13,000 landmines in the country, which was declared mine free in 2015.

The organization is now working to get a program started in Colombia, a country with a long and ugly history of landmine contamination. Most of the landmines there are what’s known as improvised or manmade, containing very little metal and strewn together with plastics and other materials.

“The only way to find the improvised mines is to turn up the sensitivity of the metal detector, but by doing so you increase your rate of false alarms,” Pursey says. “The rats ignore that, so they’re really a perfect tool for Colombia.”

Criticisms of mine detecting rats still exist, centered mainly around safety standards and integration with conventional detection methods. But successes like Mozambique offer hope to countries looking to expedite landmine clearance in a cost-efficient manner. It costs nearly $6,500 to train a HeroRAT, but given the low start up and maintenance costs, it presents a more economical fix.

“We’re getting more interest now from big operators,” Pursey says. “As [government] funding is going down, they realize they need a faster way to do their de-mining. So the skepticism is now turning to interest.”

That attitude is music to APOPO’s ears.

“It really is always a pleasure to see people’s reaction changing about the rats.”