Tens of thousands of unexploded mines is a big global problem, which mainly concerns the countries with low economic development. Every day someone steps on a landmine and those who were lucky to survive are disabled for the rest of their lives. But it seems that there is a way out. Meet HeroRAT - excellent sapper, which does not require large costs.
It may seem like an unlikely combination. Giant pouched rats are not what spring to mind immediately when conversation turns to the global issue of unexploded landmines. However, Bart Weegens, from Belgium has found a low-technology answer to the continuing issue of unexploded mines. A childhood interest in the animals came to mind when he was musing over possible solutions and this led to an extraordinary development.
The idea occurred to Weegens as he realized that rats were both easy to train and had an excellent sense of smell. Combining these two would, he considered, provide a cheap way to detect unexploded mines and – what is more – with limited danger to human life. He founded APOPO, which is a non-profit organization, the aim of which is to train up African Giant Pouched Rats and to deploy them in the field. Not only would the rats be a cheaper alternative to mine clearance methods already in use – he figured that they would be considerably more efficient as well. An army of sniffer rats, would, it seemed save hundreds if not thousands of human lives. Not bad, considering that rats do not generally have a great press with a lot of people.
Having said that, the Giant Pouched Rats used in this project are only a distant relative of the common rat we hold in such great esteem. It is an intelligent species and easy to train – with many new recruits easy to breed. The female of the species can produce up to ten litters a year. Although this is a scary fact, only one to five arrive with each litter, despite the mother having eight nipples. In many African countries they are kept as pets but also are predominantly used as a food source. Perhaps the mine field is a better option than the casserole dish after all.
Initial funding for APOPO was in Belgium. This was given by the Belgian Directorate for International Co-operation. When the rats proved successful in terms of their training it was decided to switch the whole operation to Tanzania in East Africa. There they could be trained in near-to-real conditions and so the team is now based in Sokoine University of Agriculture in Tanzania. The training there proved successful and it was while this was happening that Bart thought of another use for the HeroRATS as they were now called. It had been discovered that the rats could detect tuberculosis in human sputum (the stuff you cough up when you have a cold). Research began on this in 2004.
So, how do the rats do their detection work? There are two methods, direct detection and REST. What happens is that they are trained from young to associate the smell of explosives with a treat – such as a banana or peanut. This reward is vital to the rat doing its work as, akin to our own species – individuals do not like to do something for nothing, after all. The rats move up and down an area the size of a squash court and when they locate a mine they usually sit still and scratch themselves. After that the mines can be detonated by their human helpers.
Why these rats though? As well as having the highly developed sense of smell important in this work they are, as we have seen, easy to tame, breed and train. The cheapness of breeding and maintaining them is further helped by their ability to adapt to a number of environments. Once they are trained the rats seem to actively enjoy performing repetitive tasks and they do not get stressed if their trainers are changed in the way that dogs will. Plus of course – one serious advantage over dogs – they are too light to detonate a mine by themselves if they step on it. A living rat is better than a canine cadaver.
Training is a little time consuming – it can take up to a year. They are trained according to pavlovian principles. A food reward is initially associated with a clicking sound – their favorites being bananas or peanuts. It takes a while for them to learn that a click means food but once they do then the real training can begin. The teaching goes that when they find TNT, indicating it by scratching, then they will hear a click and get their food reward. They are initially trained in cages and once they have learned that indicating a positive sample of TNT means food then they are ready to work in a field of mines.
The REST method of detecting does not involve visiting a minefield at all. REST stands for Remote Explosive Scent Tracing and this is when scent is brought from the mines to the rats. The rats can find explosives present in these samples and it helps to determine the actual boundaries of minefields. This means that more land can be cleared at a quicker rate. Direct detection involves harnessing the rats and proceeding with a systematic search of the minefield. The rat is connected, via a search string, to two trainers and this is how the rat is directed. When TNT is detected the rat will give itself a good scratch and safe detonation can then proceed. In order to ensure that all mines have been detected two or three rats will each search the same area. It is important though, to reward the rat whenever it performs its function.
The HeroRATS are currently deployed in Mozambique where they have enabled over one thousand families to reclaim their land. They have also helped with clearing areas so that power lines can be passed through – so bringing electricity which would not otherwise have been possible to over ten thousand local citizens. It is hoped that they will soon be deployed to Zambia, Congo and Angola as well, but negotiations are still underway. APOPO is actively looking for demining partnerships globally, not just in Africa.