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Apopo HeroRATS Clear Landmines Along Cambodia-Thailand Border

January 24, 2020

By Shannon Bush

P. Derr, an Apopo mine-sniffing HeroRAT in Siem Reap, Cambodia. Apopo, which stands for Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling, or Anti-Personnel Landmines Detection Product Development, is an organization that trains and deploys rats, named HeroRATS, for the detection of abandoned landmines as well as tuberculosis.

From January 6th through the 18th, I had the opportunity to join Bill Pickett, Immediate Past President of the Washington State Bar Association, and the Honorable John C. Coughenour, United States District Judge for the Western District of Washington, on a trip to Cambodia as part of their “Building Bridges” initiative. This was their second occasion meeting with professionals in Cambodia’s legal field, having begun the initiative in winter 2019. On our 2020 trip we met with officials and scholars the pair had established ties with last year and established new connections. I’ll post reports about some of my experiences and the people we met over the course of the next few weeks. In honor of the Lunar New Year, the first installment is about a side-trip I made to the Apopo Visitor Center in Siem Reap.

Apopo in Africa and Southeast Asia

In 1995, Belgian Bart Weetjens, who was exploring solutions for the global landmine problem, came across an article about the use of gerbils to detect certain scents. Weetjens, who had pet rats as a child and knew about their acute sense of smell, had an epiphany: he could train rats to detect TNT. After some testing, he launched his project in 1997 using African Giant Pouched Rats as scent detectors. In April 2000, in collaboration with Tanzania’s Sokoine University of Agriculture and the Tanzanian People Defence Forces, Apopo established an office and training facilities in Africa where the rats not only began landmine detection but received additional training to detect tuberculosis in patients. The first group of 11 Mine Detection Rats passed official licensing tests meeting International Mine Action Standards (IMAS) in 2004.

Apopo first began working in Southeast Asia in 2010 when the Thailand Government’s Mine Action Center invited it to survey mine-contaminated areas along the Thai-Cambodian border. Two years later, the organization partnered with the Cambodian Mine Action Center (CMAC) to survey affected areas in Cambodia and in 2014 began demining activities in the country. Presently there are 51 HeroRATS working in Cambodia, dispersed in teams in three provinces: Siem Reap, Preah Vihear, and Oddar Meanchey, the latter two abutting the Thai border.

Siem Reap’s Visitor Center features maps illustrating the legacy of war in Cambodia, attributable to multiple combatants. They depict locations where the US dropped explosives during the war in Vietnam, as well as areas of landmine contamination from the country’s civil war and its war with Vietnam that ended rule by the Khmer Rouge.

One resource UW’s Vietnam historian, Christoph Giebel, uses to demonstrate the severity of the US bombing campaign inside Cambodia during the war in Vietnam is a time-lapse video that condenses bomb strikes over a ten-year period down to a rate of one second for every four weeks. Viewing the video and seeing the map not only gives lie to the claim that US bombing only occurred along the Cambodia-Vietnam border, it serves as a graphic reminder of th grave danger still posed by unexploded ordnance (UXO) decades after the end of formal combat operations. Posters within the Visitor Center, which told the stories of farmers and school children who had been grievously injured or killed by landmines while working or playing in fields, also attest to the fact that the effects of war are ongoing for many Cambodians.

HeroRATS are trained to detect both categories of explosives: various types of ordnance, as well as anti-personnel and anti-vehicle explosives. But rest assured that the rats are valuable members of the team and are not harmed in land clearing operations! As the Visitor Center guide explained, landmines require at least three pounds of pressure to detonate and the rats, although large, are too light to trigger them. Each HeroRAT works with a pair of human handlers to clear previously-surveyed swaths of land suspected to contain mines or UXO. When the rat detects the scent of TNT, it signals by scratching at the ground near the object which is then safely detonated by a member of Cambodia’s Mine Action Center.

Thanks to Apopo and its HeroRATS, these areas are being cleared much more efficiently and effectively than teams working with traditional equipment, such as metal detectors. The HeroRATS, in partnership with the staff of the CMAC, have now cleared approximately 80% of the land first surveyed for project work. But they could use even more help. The initial training for scent detection takes anywhere from 9 to 12 months and costs almost US$8,000 per HeroRAT. After that initial outlay, utilizing rats for detection significantly reduces the cost and time required for clearing operations. With a lifespan of seven years, the rats can work for us to five years before retirement. Or, in P. Derr’s case, semi-retirement at Apopo’s Vicitor Center as its spokesrodent.

To contribute to the amazing work Apopo is doing or to learn more about the award-winning organization, visit