A single African giant pouched rat can search an area the size of a tennis court in 30 minutes. A human deminer with a metal detector takes up to four days to cover the same ground. The rat weighs about 1.5 kilograms—too light to trigger the pressure plates on anti-personnel mines, which are typically calibrated to detonate under the weight of a human footstep. The rat doesn’t care about the rusty nails, shell casings, bottle caps, and miscellaneous scrap metal buried in every former conflict zone on earth, because it’s not detecting metal. It’s detecting the scent of TNT. When it smells explosives, it scratches at the ground, its handler marks the location, and a demolition team moves in. The rat gets a piece of banana. The mine gets destroyed. The land gets returned to the people who have been afraid to walk on it for thirty years.
This is not a thought experiment. This is a program that has been running for over two decades, has located more than 155,000 landmines and unexploded ordnances, has released nearly 86 million square meters of land back to civilian use, and has directly improved the safety of nearly six million people across seven countries. The organization behind it—APOPO, a Belgian-registered NGO whose Dutch acronym translates to “Anti-Personnel Landmines Detection Product Development”—was founded because a product design student in Antwerp watched a documentary about landmines and thought about his pet rats.
The origin story
Bart Weetjens was a graduate student at the University of Antwerp in the 1990s when the idea occurred to him. He’d kept rodents as pets since childhood and had recently read about gerbils being used as scent detectors. The connection was immediate: rats have an extraordinarily acute sense of smell—comparable to dogs in sensitivity—combined with a trainability that, while different from canine obedience, is robust enough for operant conditioning. They’re cheap to breed, cheap to feed, native to the tropics where most landmine-affected countries are located, and resistant to many endemic diseases. They can be trained in about nine months. They have a working lifespan of six to eight years.
When Weetjens proposed using trained rats as landmine detectors, the response from the demining community was roughly what you’d expect: he was laughed at for several years. The Belgian government gave him a research grant in 1997 anyway. He recruited his friend Christophe Cox—now APOPO’s CEO—and established a training and research center in Morogoro, Tanzania. The first 11 rats received accreditation under International Mine Action Standards in 2004. By 2006, APOPO’s rats had become what the organization describes as Africa’s preferred landmine countermeasure technology. By 2008, APOPO was the sole operator tasked with clearing Gaza Province in Mozambique.
The species they use—Cricetomys ansorgei, the southern giant pouched rat—is worth a moment of description, because the name “giant pouched rat” undersells both the animal and the weirdness of the whole enterprise. These are not sewer rats. They’re cat-sized, with large dark eyes, prominent whiskers, and cheek pouches they use to store food. They can weigh up to 1.4 kilograms. They’re nocturnal, social, and—according to everyone who works with them—genuinely affectionate. They climb onto shoulders. They lick their handlers. They have individual personalities and are given names: Magawa, Poppy, Peter Parker, Ronan. The APOPO visitor center in Siem Reap, Cambodia, lets tourists hold them, which reportedly divides visitors cleanly into people who love rats and people who discover they do not.
The training
Rats begin socialization at about four weeks old, handled daily so they’re comfortable around humans. Formal scent detection training starts at around five weeks. The rats are taught through clicker training—a click signals a correct response, followed by a food reward—to associate the smell of TNT with positive reinforcement. They learn to indicate a detection by pausing at the scent source and scratching at it. Training takes approximately nine months and includes progressively more complex scenarios: buried samples, outdoor environments, distracting scents, variable weather conditions.
Once certified under International Mine Action Standards, each rat works as part of an integrated team that typically includes manual deminers with metal detectors and sometimes mechanical ground preparation equipment. The rats don’t replace conventional methods. They accelerate them. Because a metal detector alerts on every piece of metal in the ground—and less than three percent of landmine-suspected land actually contains landmines—deminers spend the vast majority of their time investigating false positives. A rat that ignores scrap metal and responds only to explosive compounds eliminates most of that wasted time. APOPO’s integrated mine detection teams can triple the efficiency of a land release process compared to manual clearance alone.
The practical limitations are real. Rats can’t search reliably in thick vegetation. They work in short bursts because they overheat in tropical climates—typically 20 to 30 minutes per session. They search more erratically than human deminers, which means they offer a lower level of assurance that every square meter has been covered. They work best as a complement to other methods, not a standalone solution. APOPO is currently the only organization in the world that uses giant rats for mine detection, which tells you something about both the novelty and the niche nature of the approach.
Mozambique: The proof of concept
Mozambique was the program’s defining success. The country’s civil war, which ended in 1992, left an estimated two million landmines across the country—buried in roads, farmland, river crossings, and the areas around schools and hospitals. APOPO began operations in Mozambique in 2006, working with the government’s national demining authority. Tasked as the sole operator to clear Gaza Province, APOPO completed the work in 2012, one year ahead of schedule. The government then expanded APOPO’s mandate to Maputo, Manica, Sofala, and Tete provinces.
On September 17, 2015, Mozambique was officially declared free of all known landmines. APOPO had assisted with clearing five of the country’s most affected provinces, releasing over 13 million square meters of land. The declaration didn’t mean every mine had been found—residual clearance continued, with 16 rats maintained in-country for mop-up operations—but it represented a milestone that many in the demining community had not expected to reach on that timeline.
Cambodia: The ongoing operation
Cambodia presents a different and in some ways more challenging context. An estimated four to six million landmines were laid during the country’s decades of conflict, predominantly in the northern regions along the Thai border. Cambodia has among the highest rates of amputees per capita in the world—more than 40,000 people have lost limbs to explosive remnants of war. Agricultural land remains unusable. Communities remain displaced. The scale of the problem dwarfs what was faced in Mozambique.
APOPO began operations in Cambodia in 2015, partnering with the Cambodian Mine Action Centre in the Siem Reap area. In January 2018, the APOPO Visitor Centre opened to the public, offering guided tours, live demonstrations of mine detection by the rats, and exhibits on the science of scent detection. Tourists can watch a rat named Jordan traverse a simulated minefield, locate a buried TNT sample, and receive his banana reward. Proceeds from the $10 admission go directly back into Cambodia’s clearance program. The operation has also expanded to include HeroDOGs—trained detection dogs that complement the rats in areas where vegetation or terrain makes rat deployment less effective.
APOPO now operates across seven countries for mine action—including Angola, Zimbabwe, Colombia, and, most recently, efforts in Ukraine in response to the massive contamination from the ongoing conflict—and runs tuberculosis detection programs in Tanzania, Mozambique, and Ethiopia. The TB program uses the same scent detection methodology: rats sniff sputum samples through a glass chamber and indicate positive results by pausing and scratching. Since 2007, the TB program has evaluated hundreds of thousands of samples, identified over 13,000 tuberculosis patients who were missed by conventional microscopy at their clinics, and prevented an estimated 32,000 additional infections. In Maputo, the rats increased the TB detection rate by 40 percent.
The Magawa legacy
The most famous HeroRAT was Magawa, an African giant pouched rat who worked in Cambodia from 2016 until his retirement in June 2021. Over a five-year career, Magawa detected 71 landmines and 38 items of unexploded ordnance, clearing more than 225,000 square feet of land. In 2020, the British charity People’s Dispensary for Sick Animals awarded Magawa its gold medal for animal bravery—the first rat to receive the honor in the organization’s 77-year history. He was described as “physically strong” and exceptionally driven, and his handlers utilized him more frequently than other rats because of his consistent performance.
Magawa died in January 2022, shortly after his retirement. His legacy, as PDSA noted, “will live on for decades to come in the lives he has helped to save.” The statement is more literal than it sounds—every mine Magawa found is a mine that didn’t kill someone walking to school or working a field. The cumulative effect of 155,000 detected explosives and 86 million square meters of released land is measured not just in mines destroyed but in the ordinary, unremarkable activities—farming, walking, playing—that became possible again because a rat the size of a small cat scratched at the dirt and got a piece of banana.
The whole thing started because a guy in Antwerp liked his pet rats. Sometimes the most important innovations in the world look absolutely ridiculous from the outside, and the people who propose them get laughed at for years before the results make the laughter stop.
We cover APOPO’s HeroRATs alongside military dolphins, carrier pigeons, and a dozen other cases of animals deployed in service of human conflicts and crises across our Animal Heroes course—including why the best detection technology in a Cambodian minefield weighs less than a Chipotle burrito.