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Life-saving wonder rats

AS A newly qualified veterinary surgeon, I spent a year working in Africa. I was researching tickborne diseases in Swaziland, a small landlocked country the size of Wales, between South Africa and Mozambique. At that time – the mid-1980s – South Africa was still under the thumb of full-scale apartheid, with Nelson Mandela in jail, and civil war had reduced Mozambique to a complete no-go area.

Refugees used to come across the borders of both countries into Swaziland, which seemed like an oasis of peace and prosperity in comparison.

There have been unimaginable changes in the past 20 years. Swaziland has been devastated by AIDS, with almost 40 per cent of the adult population testing HIV positive. South Africa has been led to democracy by Nelson Mandela, and the civil war in Mozambique ended in 1992, with the country now enjoying peace and productivity.

I’d like to go back to southern Africa one day, to revisit old friends and places. I keep an eye on news from the area, and this week, I came across a remarkable true story that almost sounds like fiction. In Mozambique, pet rats are being used to clear mine fields.

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When I heard this at first, I presumed that the poor rats were being sent scuttling across land-mined fields, being blown to pieces when they scamper across a detonator. In fact, the mine-clearing scheme is far more clever and humane than that.

Landmines are a huge problem in Mozambique. The country's villages, farming land and roads are a patchwork of minefields, planted by both sides during the 16-year long civil war. The mines remain active, despite the fact that the war ended many years ago. They continue to kill and injure Mozambicans, preventing normal daily activities like farming and movement through the countryside.

Landmines are remarkably difficult to remove. Armored mine-clearance vehicles are only effective on level, smooth surfaces. Metal detectors locate any metal object, leading to numerous false alarms. Dogs are good at detecting the explosives in landmines, but they are heavy enough to trigger the landmines themselves, and they tend to get bored with the repetitive work.

The idea of using rats as mine detectors is brilliant. Rats have a highly developed sense of smell and are easy to tame and train, as my ten year old rat-owning daughter will tell you. They are small, cheap and easy to maintain and transport. They are very adaptable, living comfortably in all sorts of environments. And once they have been taught a task, rats love to perform repetitive tasks. They are more easily transferred between trainers compared to dogs, since for rats, the key motivating factor is the food reward rather than the social kudos of impressing their owner.

The rat mine-clearing project is run by an organization called Apopo, which is funded by the Belgian government. The rats are not the Brown Rats that are kept as pets in Ireland, nor are they the wild version of the same species. The heroic mine clearing rodents are giant Gambian pouched rats, a species that sounds suitably impressive.

They are trained at an agricultural university in Tanzania, then shipped to Mozambique for their working lives.

The rats are highly efficient workers, moving rapidly across fields, sniffing as they go. They are quick and methodical. They wear harnesses attached to an overhead guiding wire. The area to be cleared is divided into a grid by these guide wires, allowing a field to be methodically cleared. Two rats can clear an area measuring 15 metres by 15 metres in an hour. A human being with a metal detector would take two weeks to do the same job.

The rats are trained using the same type of ‘clicker training’ that is used to train pet dogs here in Ireland. When the animal carries out the desired behaviour, a metal clicker is pressed, and a tasty reward is given. The animal learns to associate the behaviour with the noise, and the noise with the food. The clicking noise can be timed very accurately to ensure that the right behaviour is being encouraged. Clicker training can teach dogs – and rats – new tricks very rapidly and effectively.

The rats are taught to alert their trainers to the presence of explosive in the ground by scratching the area with their front feet. They are not heavy enough to detonate the mine, so there is no risk to their own safety. When they are seen to be scratching the ground, their trainer presses the clicker, and the rat scampers back to the trainer to collect his reward of a piece of banana. The rats receive all of their food as rewards for carrying out this behaviour, and on days when they are not working, they are trained in ‘dummy’ set up situations.

To maintain their enthusiasm, the rats only work – or train – from Monday to Friday.

They are allowed to have the weekends off-duty, when they are fed in the normal way, with no need for explosive-sniffing to earn their dinner.

I am not sure that Giant African Pets will ever achieve popularity as pets, regardless of their intelligence, but isn’t it wonderful that they are helping create a safe environment for everyone, in that far away corner of Southern Africa?

See for more details about the mine-clearing rats