The ‘Hero Rats’ sniffing out Cambodia’s minefields

A handler shows one of the 'de-mining' rats to Cambodian villagers.

A landmine clearing rat gets a favourite reward — a banana — after a morning’s effort to sniff out mines still buried in Trach, Cambodia.

African rats are the latest weapon enlisted to clear Cambodia of up to six million landmines.

Handlers So Malen, foreground, and OK Chann guide Hero Rat Cletus across a suspected mine field in Trach, Cambodia.

One of the 14 African giant pouched rats brought from Africa to detect one of the world’s most heavily mined countries in action.

Cambodian team member OK Chann plays with one of the rats after it scurried across a minefield.

The rat in action.

TRACH, CAMBODIA // It’s been a busy morning for Cletus, Meynard, Victoria and others of their band. Tiny noses and long whiskers twitching, they’ve scurried and sniffed their way across 775 square meters of fields to eliminate a scourge that has killed thousands of Cambodians: landmines.

Meet the Hero Rats: intelligent, surprisingly adorable creatures with some of the most sensitive noses in the animal kingdom. Sent from Africa, where they successfully cleared minefields in Mozambique and Angola, they began the same task in northwestern Cambodia early this month and have already scored tangible results.

Two hectares have been declared mine-free around this village where more than 15 people have been killed or wounded by the explosives, forcing some to abandon their homes and rice fields and seek jobs elsewhere.

One villager, Khun Mao, says the rats have been sniffing for suspected mines in a rice field he had been afraid to cultivate for years. He says that while it is too soon to say whether the rodents can remove every mine, “To me, these rats are wonderful”.

“The villagers have started to get excited about farming their land again. You can see the light in their faces,” says Paul McCarthy, the Cambodia programme manager for the Belgian non-profit organisation APOPO, or Anti-Personnel Land Mines Detection Product in English.

On a recent morning, the African giant pouched rats were working two suspected, taped-off minefields. Each rodent wore a harness connected to a rope strung out in a straight line between two handlers standing about 5 meters apart and outside the danger zone. The rodents then darted from one handler to the other, constantly sniffing the ground and only taking time out to scrub their bodies with tiny front paws or to answer nature’s call. The handlers moved a step or two down the field to repeat the process, and a second rat was later sent over the same terrain to double check.

Two-year-old Victoria proved particularly swift — “very active,” one team member calls her. She stars in APOPO’s “adopt-a-rat” fund-raising drive.

At the second field, Merry and Meynard were completing three hours of effort as a midday sun beat down on the parched earth. The pair had earlier nosed in on an explosive, halting just above it and scratching the ground — the learnt response when a rodent detects TNT inside a landmine. A deminer with a detector followed and the mine was dug up and detonated.

Unlike standard mine detectors, the super-sniffers pick up only TNT and not other metal objects. And unlike wage-earning humans, the rats work for peanuts — and their other favourite, bananas.

Theap Bunthourn, operations coordinator for the 34-member team, cited other advantages of using rats: they are cheaper to acquire and train than mine-sniffing dogs and easier to transport. Rats, averaging 1kg, are also too light to detonate a pressure-activated mine, though dogs avoid that danger by staying a few feet away from the explosives they detect.

Each rat can clear an area of 200 square meters in 20 minutes, something a technician with a mine detector would take one to four days to complete. Their sense of smell is so keen that in Africa they are also used to detect tuberculosis in human sputum samples at a rate much faster than the standard laboratory method.

Unlike dogs, the rats do not get attached to their handlers and thus can be rotated among many, Theap Bunthourn says. But Mr McCarthy, a former British Army demolitions expert, recalls watching the student rats “following their trainers like puppies, stopping when they stopped.”

Critics say that rats may offer a lower level of guarantee that an area is mine-free than man-and-machine techniques, that the animals cannot search well in thick vegetation and can only work for relatively short periods in the heat.

“I would never discard any asset that could prove useful, but I can’t envision hordes of rats wiping out minefields in Cambodia,” says Greg Crowther, who heads the UK-based Mines Advisory Group (MAG) in South and South East Asia. One of half a dozen demining outfits operating in Cambodia, MAG employs Belgian shepherds and a variety of mechanical devices.

“I don’t think they can add a whole lot to what dogs can do. But if they can speed up the pace of demining, great. Let’s wait and see,” Mr Crowther says. He adds that there is plenty of work to go around: it will take up to 15 more years to clear the country’s explosives.

Mr McCarthy notes that there was scepticism about using dogs to detect landmines decades ago, “and look at them now”.

“As we accumulate more data, the more we break down the scepticism.” Mr McCarthy says APOPO, the only organisation using rats, does not have the total solution for mine-clearing but just “one fantastic tool in the toolbox”.

The group was founded in 1997 by Belgian Bart Weetjens, who bred rats, hamsters and other rodents as a boy and developed the idea of using rats to find mines while at university.

Even Mark Shukuru was sceptical when he joined APOPO in 2001 at the group’s headquarters in Tanzania. “At first I thought: `Rats finding mines? It’s impossible.’ But they proved they could do it,” he said, noting that in Mozambique they cleared more than 13,000 mines without a single injury, to humans or rats.

Mr Shukuru shepherded the Tanzanian-born rats to Cambodia, one of the world’s most heavily landmined countries, with up to six million mines or pieces of unexploded ordnance still left in the ground from decades of war. The mines at Trach were laid in the 80s by Khmer Rouge guerrillas fighting the Vietnamese army.

Countrywide, about 67,000 people have been killed or injured since 1979, and with more than 25,000 amputees Cambodia has highest ratio of mine amputees per capita in the world, according to demining organisations. A mine accident occurs every other day.

Training the Cambodian rat contingent — eight males and six females — began at four weeks by getting them accustomed to humans. This was followed by a rigorous, nine-month-long boot camp in Cambodia with APOPO, supported by the Cambodian Mine Action Centre, one of a half-dozen demining outfits in the country.

The rats learnt to associate a click with a food reward before being taught to respond to the scent of TNT. When they indicated TNT by scratching, a click was sounded and food followed. Eventually the click became unnecessary.

Before going into the field, the recruits are tested: One missed mine, and they don’t graduate to Hero Rats, registered as the trademark HeroRATs.

Now, they are falling into an operational routine, usually working six days a week and being somewhat pampered when off-duty, sleeping indoors in roomy individual cages on wood shingles and kept healthy by regular exercise walking on a leash or on a running wheel. They are given multivitamins and weighed twice a week (a fat rat is a lethargic rat, one keeper says).

On weekends there’s a special feast of apples, potatoes, watermelon and carrots. But what really drives their mine-sniffing are bananas and peanuts.

After the morning session, Victoria, Cletus and the others rested in portable cages near the fields while handlers offered them bananas, which they grabbed and greedily devoured. Grateful villagers gathered around the cages.

“It’s not often you hear people say that they love rats,” Mr McCarthy said.

* Associated Press