for National Geographic News
Dogs have long been used to sniff out land mines in war-torn regions. But now they may have some welcome competition: rats and bees.
A Belgian company has trained African giant pouch rats (Cricetomys gambianus) to locate buried bombs, while researchers at the University of Montana are using honeybees to screen large areas for unexploded ordinance.
The efforts highlight the quest to find low-cost alternatives to safely detect underground explosives.
An estimated 80 million mines lay buried in more than 60 countries. Each day 50 people, many of them children, are killed or injured, according to the Landmine Survivors Network in Washington, D.C., an organization that provides peer counseling and prosthetics to victims throughout the world. The cost in human life is compounded by mines' impact on regional economies, where land is put off-limits to farming and development.
In Mozambique, an African country littered with land mines from decades of civil war, 20 rats were recently used to search for explosives. So far, they've been successful. In November, the animals found nine mines in one day along the Limpopo Railway, says Bart Weetjens, director of APOPO, the Belgian research company that trains the animals.
The Mozambique National Demining Institute accredited the technology in late September, allowing for the work to take place. Weetjens notes this is the first time the African giant pouch rats have been deployed in real mine fields.
The rats combed three minefields along a rail line that connects the port city of Maputo with neighboring Zimbabwe. Despite the railway's economic importance, few trains travel this dangerous stretch. People fear vibrations caused by trains will trigger the instable explosives.
Cheaper Than Dogs
APOPO came up with the idea of using rats while searching for a cheap and efficient way to detect mines. A trained rat costs about U.S. $2,000—about $10,000 less than a mine-sniffing dog. Other advantages include the rats' relatively small size (15 inches/40 centimeters), which make them easy to maintain and transport; their resistance to most tropical diseases; and their highly developed sense of smell.
"Rats are able to detect most types of mines," said Weetjens. "In principle they could detect all mines because of the explosive content, if it weren't that some devices have been manufactured with accurate sealing, which leaves no escape for explosive trace vapors. But these can easily be found with a metal detector."
Rats conditioned to TNT odors are trained to walk on a leash, which is attached to a bar that moves forward into a suspected field. When the animals smell explosive material they scratch or bite at the location. The rat's light weight—one-and-a-half to three pounds (0.7 to 1.5 kilograms)—does not trigger the mine.
A rat and handler can search 180 square yards (150 square meters) in about half an hour.
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