... Upon study, the rats' advantages emerged.
Their olfactory senses are superb. They're native to Africa, so tropical disease is no problem, and they don't grow heavier than the 3 to 10 kilograms required to trip a mine, Bach said. It also helps that the mine-sniffing rats are not bonded to individual trainers or prone to ennui, as dogs are, he said.
"If you compare them to canine mine detectors, it's pretty much the same in terms of sensitivity and capability," Bach said, noting that dogs are better equipped to work in brush or high grass that might conceal a rat.
"Rats are not going to oust dogs in this industry, but it's a very positive complement," he added. "You could say they work for peanuts."
Indeed, said Weetjens, cost is especially an advantage in Africa. It takes limited skill and only six to eight months to train a rat -- or a year for the "slow" rats because "some rats are smarter than others," said trainer Mushi, who oversees 14 rats.
The cost to train a rat is 6,000 euros ($7,700), roughly a third of what it costs to train a dog....