Tell a New Yorker that rats can save lives and he might consider it an impossible trick for the beady-eyed sewer dwellers.
But for the past 10 years, a group of Belgian researchers based in Tanzania have been training a species of giant African rats to sniff out land mines and unexploded ordnance.
“When people see they can use these animals for humanitarian purposes, it changes their perception,” said Bart Weetjens, whose nonprofit group, Apopo, has pioneered the use of the African or Gambian giant pouched rat in mine detection. “People find it most fascinating.”
By teaching local residents how to handle the rats — a food source for some Africans — the group hopes to develop a cheap, reliable, indigenous resource for de-mining, an expensive and dangerous process that typically operates in unstable, war-ravaged regions.
“The whole philosophy of the project is to provide local people with tools and techniques so they can manage to deal with the problem themselves,” Mr. Weetjens said.
Mr. Weetjens and Apopo hope the creatures, the largest rats by size in the world, will join hand-held metal detectors, armored vehicles and dogs in the effort to detect and remove land mines, which kill or maim as many as 20,000 people a year, according to the International Campaign to Ban Land Mines.
The campaign, a grouping of about 1,400 nongovernmental organizations from 90 countries, issued a survey last year that listed more than two dozen African countries dealing with buried anti-personnel mines and mine contamination. The problem was especially acute in Angola, Mozambique, Sudan, Ethiopia and Eritrea.
Angola — along with Afghanistan, Cambodia and Colombia — is thought to have one of the world’s most severe problems, with an estimated 7 million land mines hidden in unmarked fields four years after the end of a long civil war, the government said.
With its headquarters at the Sokoine University of Agriculture in Morogoro, Tanzania, Apopo has 50 rats working in Mozambique and plans to expand to Angola within two years if it can secure enough funding. Thirteen other African countries have expressed an interest in the program, Mr. Weetjens said.
“They see it as an African technology,” he said.
In the 3½ years that Apopo has been using fully trained rats in Mozambique, the rodents have cleared about 100 acres of land and found 23 mines. “A few animals … died from old age or food poisoning,” Mr. Weetjens said, but none has been destroyed in an accident.
In the laboratory, young rats — which have long been adopted as pets in Africa and the United States — are first domesticated and taught to associate food with a clicking sound. Then, using the food and clicking as a reward, they are presented with three holes and trained to identify the one releasing the chemical vapors similar to those found in explosives.
In the field, the rat is leashed and made to run in straight lines across a 1,000-square-foot area during 30-minute shifts. Every time it stops to investigate the ground, the handler marks the spot on a paper grid and feeds the rat on the assumption that it has found a mine.
Metal detectors are used to double-check the rats’ work before they extract or explode the mines, Mr. Weetjens said.