Potentially lethal searches for land mines may soon be far safer with the creation of mechanical sniffer dogs that can smell almost as well as the real thing.

Scientists and engineers in the United States have unlocked the secrets of a dog's extraordinary sense of smell and used the discovery to produce a mechanical replacement, according to a story in New Scientist. Gary Settles, a mechanical engineer at Penn State University, used special photography to record images showing the air currents produced by sniffing dogs.

The images showed that part of sniffer dogs' success was due to the fact that they separated scent-laden inhaled air from exhaled air, preventing the scent from becoming mixed-up.

A team at Tufts University, Massachusetts, was using Settles' research to develop an artificial nose that "breathes" air in and out like a dog, the magazine said.