They may not be man’s best friend, but rats and bees are competing with dogs in the search for landmines. Scientists have discovered that the unpopular rodents and insects are surprisingly accurate detectors.
No exterminator necessary. These rats may just save millions of lives
Landmines, one of the most dangerous forms of pollution on earth, scatter the fields and countryside of war-torn countries like Afghanistan, Cambodia, and Angola.
The International Red Cross estimates that 80-120 million landmines are buried in 70 countries. Every day some 60 people are maimed or killed by buried mines.
Europe and other western countries have been busy developing new methods for detecting the buried mines. Everything from high-tech radar devices and satellite locating systems to teams of sniffer dogs have been tried out. Most of the techniques, however, are too expensive for the impoverished countries most often effected by mines.
In the future though, detecting mines may get cheaper and make good use of two annoying pests: bees and rats. Like the more common sniffer dogs, the insects and rodents have inbred biological detection systems, and once scientists learn how to employ these, the creatures could be set loose to uncover mines.
A joint project by Sandia National Laboratories in New Mexico and the University of Montana has demonstrated that foraging bees can be used to collect samples of TNT, the primary ingredient in landmines, and bring the evidence back to the bee keeper.
When they collect pollen from flowers, such as this crocus, bumble bees also pick up trace elements of explosives.
When bees fly from plant to plant collecting nectar and pollen they also attract particles of dust, soil and other air-born elements to their fuzzy, statically charged bodies and bring the samples back to the hive.
"Bees are like flying dust mops," says Jerry Bromenshenk, director of the University of Montana study. "Wherever they go, they pick up dust, airborne chemicals and other samples. If it’s out there, they’ll find it and bring it back."
The experiment is based on the premise that all landmines leak small amounts of TNT into nearby soil and water and that plants growing in such regions will contain traces of these elements in their pollen.
But before bee keepers can train their hives to do search and recover missions, more studies need to be done to determine whether bees can be trained to smell explosives and associate TNT with food (sugar syrup as found in pollen).
It may still be a ways off, but Bromenshenk foresees attaching small diodes onto the backs of several hundred TNT-trained bees and then following them with a radar tracking device.
"The beauty of this approach is that bees are indigenous to every climate on earth," says Susan Bender of Sandia Laboratories. "And you wouldn’t need a million-dollar piece of equipment and extensive training to use it."
A team from the University of Antwerp has successfully tested mine-sniffing giant pouched rats in Tanzania. According to information published in the Frankfurter Allgemeine Sonntagszeitung, the Belgian group of scientists trained a troop of rats for three months before deploying the rodents in the search for different types of mines.
Scientists have long known that rats, like dogs, have a highly-developed sense of smell. In laboratory experiments rats have been trained to detect explosive trace vapors. But in other characteristics, rats far exceed their canine competitors.
Their light weight, for one thing, ensures that the bombs will not accidentally go off when they scurry across a field. They are endemic to nearly every continent and climate and are resistant to most tropical diseases. They are also cheap, and easy to breed.
Rats are inherently inquisitive and they have an intrinsic motivation to search. They are well suited to repetitive tasks and are conditioned to respond to a food reward so they have a strong motivation to remain concentrated.
In the Tanzania experiment, a group of African giant pouched rats were taken to an actual mine field and allowed to search on a long leash until they smelled the explosive vapor. Like a blood hound they then began pointing and digging at the correct spot.
Eight of the rats were successful in detecting mines, leading the Belgian scientists to believe that the unpopular creatures have a bright future as mine sweepers, especially when compared to man’s best friend, the dog.
Over the next years the scientists will continue training and refining the rats’ search techniques. They will also improve the species through selective breeding. Their goal is to use the rats as a cheap and efficient method for clearing suspected landmine areas for developing countries.