The mine clearance rat Magawa dies at the age of 8
One of Cambodia’s top deminers died earlier this month after a highly successful career. His name was Magawa and he was an African giant opossum.
Magawa was part of an initiative by the Belgian non-profit organization APOPO, which uses specially trained dogs and rats to detect the explosive compounds in land mines and unexploded ordnance. Most of her work focuses on South Sudan and Cambodia, where the deadly remnants of late 20th-century wars have killed nearly 20,000 people and injured about 45,000 others since 1979.
Deadly relics left behind by decades of war
Some of the explosives, particularly in eastern and northeastern Cambodia, are relics of the United States’ 1965-1973 war in neighboring Vietnam. The American threats are primarily unexploded artillery shells fired during fighting along Vietnam’s western border, which landed across the border in Cambodia but failed to explode on impact. Similarly, about 1 in 4 cluster bombs dropped during the four years of US carpet bombing from 1969 to 1973 hit the ground without detonating. Many of these also ended up in Cambodia.
From 1993 to 2017, the U.S. government spent $133.6 million cleaning up minefields and unexploded ordnance in Cambodia — part of a total of $400 million in clean-up aid paid to Cambodia, Laos and Vietnam. Thanks to this funding, along with the efforts of several international non-governmental organizations such as the HALO Trust and APOPO, around half of Cambodia’s minefields have been cleared.
What remains is an approximately 750-kilometer stretch of north-western Cambodia along the country’s border with Thailand, an area known as the K5 mine belt. About 1,640 square kilometers of minefields remain to be cleared in the K5 belt, where Vietnamese forces laid minefields in the 1980s after the 1979 invasion of Cambodia.
“Many of the remaining areas are most heavily contaminated, including 21 northwestern districts along the border with Thailand, which contain anti-personnel mines laid by the Vietnamese military and are responsible for the majority of mine casualties,” a 2019 congressional report said.
Another NGO, the HALO Trust, clears hundreds of mines in the area each month.
And it’s a race against time for the many families who have migrated to north-west Cambodia from other parts of the country in recent years, fueled by economic pressures and hopes of making a living from farming in the rural provinces . The mines not only make it dangerous to till the land or even go to school along the Thai-Cambodian border, they also make it difficult to build infrastructure to irrigate fields or provide clean drinking water.
“Aren’t you a bit short for a minesweeper?”
That’s where the rats come in, along with dogs, metal detectors, and other tools. APOPO’s website claims the organization is currently working with about a dozen dogs and 96 rats in Cambodia and South Sudan and is considering expanding to other war-torn countries. While metal detectors track down the metal parts of landmines and duds, the dogs and rats are both trained to sniff out the chemical compounds in the explosives themselves.
Bomb-sniffing dogs are a familiar sign to most modern air travelers, and dogs have been helping warn soldiers of hidden explosive devices such as landmines since at least World War II. But working rats?
APOPO claims that African possums like Magawa are intelligent enough — and have sensitive noses — to get the job done. Under good conditions, a rat like Magawa can sniff out a relatively small amount of TNT buried about 15 centimeters deep from about a meter away. And the rats are smart enough to learn from their trainers how to find the right smell for a reward.
Dogs can do it all, so why train rats? As it turns out, when it comes to pressure-activated anti-personnel mines, size does matter. It takes about 5 kilograms of pressure to activate the pressure switch and detonate the mine. But the heaviest male African possums weigh about 1.5 kilograms, well below that threshold.
But APOPO says it’s not about using dogs or Rats to clear Cambodian minefields.
“Dogs and rats play complementary roles in landmine detection,” explains APOPO. “The perfect mission is a mix of dogs and rats.” The organization sends its explosives detection dogs to survey large areas of dense vegetation, while the rats search smaller areas with less undergrowth more closely.
Win the rat race
Magawa, APOPO’s most successful minesweeper of all time, found more than 100 landmines in five years of work. In 2020 he received a medal from the British charity People’s Dispensary for Sick Animals – becoming the first rodent ever.
Like APOPO’s other demining rats, Magawa was born and raised at the organization’s breeding center in Tanzania. After spending the first few weeks of life with his mother and littermates, Magawa spent more time with his human trainers and was carried around cuddled.
At around 10 weeks of age, Magawa’s trainer introduced a new concept: a device called a clicker that makes a clicking sound when the trainer presses a button. Every time Magawa heard that clicking sound, he got a treat. It didn’t take long to connect: the clicking sound means food is coming!
“Once the rats learn clickers/rewards, they are trained to discriminate between everyday smells and their target smell,” says APOPO. “The rats are introduced to a strong target odor, the strength of which is gradually reduced while dummy odors are gradually added and the training range expanded.”
APOPO is just one of several organizations – part state, part non-state – working to clear landmines and unexploded ordnance from Cambodia’s former battlefields. And these joint efforts are paying off. The Cambodia Mine/ERW Victim Information System, which tracks landmine victims across the country, has reported a steady decline in the annual number of landmine deaths and injuries. In Cambodia, 58 people were injured by landmines in 2017, up from 286 in 2010.
Magawa began searching for real explosives in Cambodia in 2016 and retired last year.
“Every discovery he made reduced the risk of injury or death for the people of Cambodia,” APOPO said.