In Mozambique, special squads of raccoon-size rats are sniffing out lethal explosive devices buried across the countryside, remnants of the country’s anticolonial and civil wars of the last century.
In neighboring Tanzania, teams of rats use their twitchy noses to detect TB bacteria in saliva samples from four clinics serving slum neighborhoods. So far this year, the 25 rats trained for the pilot medical project have identified 300 cases of early-stage TB – infections missed by lab technicians with their microscopes. If not for the rodents, many of these victims would have died and others would have spread the disease.
“It’s fair, I think, to call these animals ‘hero rats,’ ” said Bart Weetjens, the Belgian conceiver of both programs.
Support from the World Bank, UN, and various land mine eradication groups may encourage the spread of Hero Rat action to more countries, including Angola, Zambia, and Congo.
For both TB and land mines, the rats are trained to respond to the sound of a clicker; when the rat makes the scratching motion that means it has detected an explosive or the odor of disease, the handler or trainer responds by snapping the clicker, which means a nut or fruit is on the way.
So why don’t the animals just scratch every few minutes to win a treat?
“That would be human behavior,” said Weetjens. “Rats are more honest.”