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Giant African Rats Detect Land Mines and TB for a Living

So yesterday, I adopted an unborn land-mine-detecting African giant pouched rat (Cricetomys gambianus) from Tanzania. Did I spend 20 minutes figuring out what I was going to call it, as one of my many privileges as an adoptive parent?

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


So yesterday, I adopted an unborn land-mine-detecting African giant pouched rat (Cricetomys gambianus) from Tanzania. Did I spend 20 minutes figuring out what I was going to call it, as one of my many privileges as an adoptive parent? You bet. It eventually came down to a character from my favourite video game, and as I figured The Chosen Undead would be tempting fate just a little too aggressively under the circumstances, Knight Solaire of Astora was born. Or rather, will be born in two weeks, as an email promptly informed me once I’d made my first monthly payment for my new son or daughter’s future tuition.

APOPO - which stands for Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling in Dutch, or Anti-Personnel Landmines Detection Product Development in English - is an organisation that trains and deploys rats, named HeroRATS, for the detection of abandoned land mines and tuberculosis. Founded in 1997 by Belgian rat-enthusiast, Bart Weetjens, APOPO partnered with the Tanzanian People’s Defence Force and the Sokoine University of Agriculture in a city called Morogoro in the southern highlands of Tanzania, where they now maintain their headquarters and training facilities.

Since 2000, they've bred hundreds of trained and accredited rats that have so far found 1,500 buried land mines across an area of 240,000 metres squared in Tanzania, and 6,693 land mines, 26,934 small arms and ammunitions, and 1,087 bombs across 9,898,690 metres squared in Mozambique. They’re also operating in Thailand, Angola, Vietnam, Cambodia and Laos. And don’t panic - they’re too light to be setting off any buried explosives.


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A spin-off project that trains tuberculosis-detecting rats has so far produced 54 accredited rats for use in 19 TB clinics in the Tanzanian city of Dar es Salaam. Since 2002, they’ve screened 226,931 samples and identified 5,594 TB patients.

Other than being super-smart, these are by no means ordinary rats. In fact, they’re not even ‘true’ rats at all - they belong to an entirely different family (Nesomyidae) from your regular house rat (Muridae). Growing to around 0.9 metres (3 feet) long - their tails make up half their length - and 1.4 kilograms (3.1 pounds) in weight, African giant pouched rats are pretty humungous. They’re native to Sub-Saharan Africa, ranging from Senegal to Kenya and from Angola to Mozambique, where they live in communities of 20 or so, relying on their keen senses of hearing and smell to make up for their relatively poor eyesight.

Get ready for it, because this is the adorable part - the 'pouched’ reference in the species’ name doesn’t refer to the kind of pouch that carries babies, but rather the kind that sits on the inside of the cheeks for extra food storage. So these guys are pretty much giant, really intelligent hamsters.

Land mine detection training typically takes about nine months from when a rat pup opens its eyes at four weeks old. First the pups are socialised, encouraged to interact with their caretaker and trainer, their kennel-mates, and the outside world. They’re exposed to a range of different stimuli, including radios, flowers, coffee, and different surfaces such as grass, concrete and soil, to ensure they’re comfortable and familiar with whatever they’ll end up encountering. Very important is getting them familiar with the HeroRAT lorry, which will eventually transport them to and from their training grounds.

“During one week, I will be taking the pups outside the kennels for about 20 minutes every day. I let them smell different odours like tea, coffee and oil, they get to hear different sounds like a ringing phone and human voices and they get to wander around on different surfaces as sand, wood, grass and concrete,” caretaker Albert Carol says at the APOPO website. "I make sure they are exposed to all kind of smells, textures and sounds, but especially to being handled by people. Every individual pup gets plenty of attention and learns to be held and carried by the trainers.”

Next, the rats are trained in associating a 'click' sound with a food reward - bananas are their favourite. They work with a target scent, TNT, to earn a click and a reward. The difficulty is increased when they’re exposed to various scents before progressing to sandbox training, where the target scent will be buried under sand and the rat must walk in ‘lanes’ up and down systemically to scout the entire area.

And then they finally make it to the training grounds. Here’s what it looks like:

Once this training is complete, the rats are put through a rigorous and independent two-day exam, during which they must undergo a 'blind test' where not even their trainers know where the sample land mines are buried, so they can’t unwittingly give their rats visual cues. Only if the rats score 100 percent in this test will they be accredited and their trainers officially licensed to operate on actual minefields around the world.

African giant pouched rats usually live to eight years old, making them a pretty great investment. This also goes for the TB-detecting rats, one of which can evaluate in 10 minutes more samples than a lab technician can do in an entire day.

I’ve only just adopted one of these rats (for $7 USD per month), and Knight Solaire of Astora is expected to be born in two weeks, so I can’t say much about the experience yet, but you do get a really sweet certificate and a portal on the website where you can log in and see how your HeroRAT’s training is going, and then eventually, how many land mines it's detected.

And now here’s a ridiculous song about them that will definitely get stuck in your head:

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