Why you’ll never hate rats again
Harnessing their superlative sense of smell, a Tanzania-based organisation has trained the much-maligned rodents to detect landmines and diagnose TB — saving lives by a whisker
By Guy Kelly. Photographs by Mia Collis
In the pre-dawn glow of Morogoro, a town in eastern Tanzania, Peter Parker is preparing for a morning’s graft. It is quiet and crisp, the sunrise postponed by the height of the surrounding Uluguru Mountains, but Parker and his roommates — colleagues, really — have been restless in their dormitory for much of the night.
They are in training, and like all eager cadets, by the time they are roused at 6.30am, some are already exercising, some hydrating, some in contemplation, but all are focused. They know the routine by now: a pair of supervisors help them, one by one, on to a bus, then drive them a few miles down a dirt track to a large field, where they are met by dozens of overall-clad trainers. There, they are weighed, have their ears and feet sprayed with factor-50 sunscreen, and are dressed in specially made harnesses, before being split up to be tested separately.
Parker, a consummate professional, takes his place on the bus between Sharon and Oprah. It will strike some as amusing that he has the same name as Spider-Man, but he does not care because he hasn’t heard of him. And besides, what he and his colleagues are training for is every bit as heroic as the exploits of his web-slinging namesake. In a few months, all being well, Parker — who is only 18 months old — will become a specialist in detecting landmines left hidden in some of the world’s deadliest post-conflict zones.
Lives will be saved. The planet will be a safer place due to his expertise. Right now, though, he is attached to a trainer on either side of a plot the rough size and shape of a cricket wicket. He knows he must comb the area in widths, and signal if he finds anything of note. All around him, others are preparing to do the same. Parker takes what I imagine to be a deep breath, and sets off. Within seconds he pauses, indicating the ground beneath him. One of the trainers nods proudly, marking her clipboard. He has found something. He will be rewarded with a mouthful of fruit.
Peter Parker is a rat. Or, to be more respectful, he is an African giant pouched rat. They are larger than our streetwise friends, growing up to three feet long, tail and all, and have bigger ears and longer snouts — but they’re ultimately just as ratty. For the past two decades, Apopo, a non-governmental organisation founded in Belgium, has been utilising their extraordinary sense of smell to find explosives all over the world. The rats have also been trained to detect tuberculosis, while numerous other applications, all based around smell, are being researched.
They are astonishingly effective. Over 20 years, Parker’s forebears have helped clear more than 100,000 mines, giving back almost 25 million square miles of land to a million people who had previously lived in fear. Most who encounter Apopo’s work at a glance assume the rats are employed because they’re more expendable than a human with a metal detector. The truth is, they don’t get blown up — they are far too light (their average weight is around a kilo) to trigger even the most sensitive mine. They’re also much quicker than us: one rat can search over 2,000 square feet of land in around 20 minutes. A human would take a week.
https://www.youtube.com/watch?v=EXaoscx3Wtk
The idea was born in the mid-1990s, when Apopo’s founder, Bart Weetjens, read an article about gerbils being taught to sniff out explosives. Weetjens had bred rodents as a teenager, occasionally hiding treats for them around the house and observing their olfactory powers. He wondered if rodents could be put to work in minefields, and contacted a friend from university, Christophe Cox.
‘It sounded good. Rats were being used for other scent-detection tasks, and I thought it would work,’ Cox, now Apopo’s CEO, recalls. ‘We got support from biologists, received a government grant to test the idea, and set up rat kennels in an old factory in Antwerp. It all moved quite quickly.’
There are more than 50 species within the genus Rattus, but Weetjens and Cox were told by experts that Cricetomys gambianus — or the African giant pouched rat — would be best-suited to their task, given it is ubiquitous in much of rural Africa, lives for up to eight years, can be taught quickly and, unlike a dog, won’t only obey one trainer. The only downsides are that it is principally nocturnal and so sunburns easily, hence the factor-50.
Apopo’s first rat bred in captivity, Onzo, was born in 1998. Seven months later, trials showed emphatically that rats could detect buried explosives, so in 2000 Weetjens and Cox set up in Tanzania.
The organisation’s headquarters and training centre in Morogoro is a small collection of single-storey buildings surrounded by palm trees. Staff come from all over the world, drawn by the unusual nature of the work. They love the rats — who also have dedicated fan groups: I am shown a collection of handmade miniature felt hats (a Santa hat, a chef’s hat) sent in by a British woman.
There are offices and staff accommodation, as well as a rat playpen and two rat kennels — one for the boys, one for the girls — housing 200. Inside the kennels, every rat has his or her own cage, containing an exercise wheel, ramps, nests and bark or newspaper shavings, which they personalise but keep meticulously neat. In captivity as in the wild, where African giant pouched rats live underground in burrows, they take the time to create separate chambers for sleeping, eating, playing and excretions. There is also an on-site retirement home, where rats that have reached seven or eight years old, experienced a performance dip or suffered health problems, see out their days in comfort.
It takes around nine months to train a rat to sniff out explosives. Babies, known as ‘pups’, are kept with their mothers for 10 weeks, when they are named and chipped (they are easily confused at a young age, so occasionally a Sharpie is needed to mark their tails too), before being started on a rigorous training programme.
The rats are naturally affectionate but skittish (even scaring themselves with their own sneezes), so early exercises harden their tolerance to noise. One test, approved by animal-welfare officers, involves placing a baby rat on the bonnet of a car. A trainer then honks the horn and starts the engine. When the rat doesn’t flinch, it’s passed. There’s no point having a scaredy-rat in a minefield.
There is little method to christening the rats, besides whim and wit. Some are named after rock stars (Bowie, Blondie, Dylan), some after footballers (Ronaldo, Hazard), others after politicians (Clinton, Winnie, Magufuli), and a few just have wonderfully everyday monikers. Like Stephen. Poor old Stephen.
In one corner of the compound, Obeni is being put through his paces in a sandpit. He is wearing a small harness, homemade by one of Apopo’s staff. The rats are taught to identify explosives (TNT) using click training — associating the sound of a click with a food reward. Trainers place the scent of TNT inside stainless-steel ‘tea eggs’. When a rat is near these, a click is heard. They soon get it.
The next challenge is to distinguish between TNT-positive and TNT-negative tea eggs, especially once they are buried in the ground. The rats’ harnesses are clipped to a string, attached at either end to a trainer. (In a real minefield, humans sweep narrow ‘corridors’ to make safe pathways, leaving rectangular expanses for the rats to scour, so the animals are trained in the same way.) To indicate he’s found something, Obeni must make a shallow scratch at the ground. Dig in the right spot, and a click is heard. He scampers to one of the trainers, who feeds him a mouthful of crushed avocado, banana and peanuts — it’s very Gwyneth, the rats’ diet — before he returns to look for more.
Once the sandpit has been mastered, Obeni will be taken to the field where Parker currently trains with real deactivated mines. Before they pass training, rats must complete a blind test, finding all landmines in a 400m2 area with no more than one false identification. Achieve this, and they become what Apopo calls a ‘HeroRat’, ready for action.
Apopo, whose biggest donors are the players of the People’s Postcode Lottery, has so far deployed its rats in Angola, Mozambique, Zimbabwe, Laos, Vietnam and Thailand, and there are plans to move into Colombia. But the primary site at the moment is Cambodia, one of the most heavily mined countries in the world. Dr Cindy Fast, an American who is head of training and behavioural research at Apopo, recently returned from seeing her charges in action there.
‘I saw a rat right in front of me indicate very strongly that it had found something,’ she says. ‘Based on how she was scratching I knew there was something there. They brought in the metal detector and, sure enough… The humans dug pretty deep, and there was a massive unexploded ordnance. I see it in training every day so I know they can do it, but to see it in real life gave me goosebumps. It saved a life, that rat. No question.’
Humans tend not to like rats, generally with good reason. The old adage about us being no further than six feet from one at any time — especially in London — is a myth, but it is generally agreed that they number in the billions. Their collective noun is a ‘mischief’.
They carry pestilence, bite babies, decimate crops, compromise buildings, and can squeeze their tiny, flexible skeletons through any crack wider than half an inch. They eat one another, thrive in squalor, chew and scratch at anything they bump into (in part because their teeth and nails never stop growing), move in a way that cannot fail to feel threatening, and a pair could — if they had the energy and romantic spark — produce 15,000 pups in a year.
While a few cultures revere them, centuries of Western literature, folklore and popular culture make clear we do not. History too — even if a recent study suggests the Black Death may have been spread by lice and fleas. If you ‘smell a rat’, you suspect somebody of grave deceit. If you are upper-class and English, you might bellow ‘Rats!’ when you witness a Tory lose a by-election. People from the Isle of Man can’t even say the word, lest bad luck befall them (they prefer ‘longtails’).
Mice have Mickey, Danger Mouse, Stuart Little and dozens of other adorable ambassadors. Rats have Ratty from The Wind in the Willows — who may or may not be a water vole, anyway — and Remy from Ratatouille. But they also have dramatically negative portrayals in works by Beatrix Potter, JK Rowling, Arthur Conan Doyle and George Orwell. Rarely are they celebrated.
I consider this as I watch Carolina, one of nine Apopo-trained rats working at a laboratory in Dar es Salaam, a few hours east of Morogoro, identifying tuberculosis in a human. Apopo has used rats to detect TB since 2007, and has so far screened more than half a million samples, halting over 117,000 potential infections. A quarter of new cases of TB are found in Africa, so Apopo’s work — in Tanzania, Mozambique and Ethiopia — is invaluable, especially as diagnosis can be difficult and expensive.
When somebody has TB, their sputum (saliva and mucus coughed up from the respiratory tract) contains compounds produced by a bacterial pathogen. These have an odour. Some doctors have claimed to be able to smell it on very ill patients, but it is recognisable to some animals at an early stage.
Animals such as rats, especially if they are taught by Apopo, which uses a similar training technique for TB detection as it does for explosives. In Dar es Salaam, sputum samples from 100 patients who have presented symptoms to Apopo’s partner clinics have just arrived by motorcycle courier. After being rendered sterile, the petri dishes are opened and placed into racks by Apopo staff.
The smell is unbearable. ‘Is that… TB?’ I ask, inwardly wondering if I have a rat’s super sense of smell. Nashon Edward, the laboratory supervisor, smiles. ‘No, if that was TB, we would all be in a lot of trouble. That’s just the smell of sputum.’
The rats will still be able to identify which dishes contain the relevant bacteria. Carolina is the favourite of training supervisor Fidelis John. She was named after his daughter, born months before her. He adores the rats.
‘You only have one life and these animals save lives. I feel very proud to be working with them. We have a beautiful relationship,’ John says. ‘Before I started here I thought they were pests, but now I know how intelligent they are. The world needs to learn the good that comes from rats.’
In a testing room, John sits opposite a spotless glass tank. A rack of 10 samples is slid into a tray beneath, leaving the sputum exposed to the air. Carolina is dropped in at one end for her daily shift. She scampers from one sample to another, sniffing exuberantly, her claws clattering on the stainless steel, and stops at the third. She scratches. John clicks, and Carolina totters back to the start, where a pipette delivers her a snack.
On his clipboard, John has a chart showing where control samples are. Carolina finds them with ease, but also scratches at two other dishes. These may have been marked as negative by doctors; now they’ve been identified by Carolina, they’ll be re-checked using WHO-approved confirmation tests.
Nobody is ever diagnosed solely on the strength of a rat’s verdict, but if these samples do indeed contain TB, Carolina could well have saved a life. And it took her minutes: a rat trained by Apopo can evaluate 100 samples in 15 to 20 minutes. A human with a microscope could take as long as a week.
Muhammad Said, a 24-year-old welder from Dar es Salaam, knows how it feels to have his life saved by a rodent. In April 2018 he was coughing and sweating through the night, but a doctor told him he was negative for TB. His sputum was sent to Apopo for secondary screening, where a rat disagreed. The rat was right.
‘I had no idea rats could do this,’ Said says. Today he is visiting the facility, and handling a rat for the first time. After six months’ convalescence, he is healthy again. Had his symptoms gone unrecognised, he might not have lived another month. ‘I went on medication for TB and now I am working and playing football again. It’s strange being here. I thought rats were vermin…’
There is still a stigma around rats, Christophe Cox says, even among those who know Apopo’s work. ‘We’ve come up against the mine-action community — who are quite a conservative, often military-based industry — who viewed it as a kind of black magic. But this is changing. People are becoming more interested in our work.’
Funding permitting (you can help, including by ‘adopting’ a rat), Apopo now has grand plans to put the rodents to further use. Research has begun to ascertain if rats could be trained to detect samples of endangered animals, such as pangolin scales, in the luggage of smugglers. Or to pick up the smell of contaminated water. And rats equipped with ‘miniature hi-tech backpacks’ could be sent into the rubble of collapsed buildings, where even dogs can’t fit, to find survivors.
‘The trouble with that one,’ Cox adds, dryly, ‘is what happens if the rat comes across a well-stocked kitchen on his way through the building?’
In Morogoro, where a marmalade sun is up and gently beating down on the rats and their trainers, Peter Parker is his usual industrious self. Twenty rats have been summoned to Cambodia, where they are urgently needed, and Dr Cindy Fast insists Apopo will ‘only take the best of the best’.
Parker hurries up and down his patch. He is faster than most. Scurry, scratch, click. Scurry, scurry, scratch? Yes. Click. I leave him to it, but a few weeks later I’m told he’s passed with flying colours. Paperwork permitting, he is on the next flight to Cambodia.
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This article was originally published on The Telegraph.
© Telegraph Media Group Limited 2020
