Is that a bomb I smell before me? (Image: Barrie Watts/Alamy)

ONE day, there may be more than X-ray machines and full-body scanners awaiting you at the airport. Listen out for the snuffling of sniffer mice as you pass through security.

The critters will not be angling for a snack, though. They are part of a bomb-detecting unit created by Israeli start-up company BioExplorers, based in Herzeliya, which claims that trained mice can be better than full-body scanners and intrusive pat-downs at telling a bona fide passenger from a terrorist carrying explosives.

Eran Lumbroso conceived the mouse-based explosives detector while serving as a major in the Israeli navy. Along with his brother, Alon, he founded the company and built a device that looks much like an average airport metal detector or full-body scanner.


Along one side of an archway, a detection unit contains three concealed cartridges, each of which houses eight mice. During their 4-hour shifts in the detector, the mice mill about in a common area in each cartridge as air is passed over people paused in the archway and through the cartridge. When the mice sniff traces of any of eight key explosives in the air, they are conditioned to avoid the scent and flee to a side chamber, triggering an alarm. To avoid false positives, more than one mouse must enter the room at the same time.

“It’s as if they’re smelling a cat and escaping,” Eran says. “We detect the escape.” Unlike dogs, which are often trained for explosives and drugs detection, mice don’t require constant interaction with their trainers or treats to keep them motivated. As a result, they can live in comfortable cages with unlimited access to food and water. Each mouse would work two 4-hour shifts a day, and would have a working life of 18 months.

What’s more, mice beat dogs for olfactory talent, and by much more than a nose: dogs have 756 olfactory receptor genes, while mice have 1120, resulting in a more acute sense of smell.

Attacks such as the recent bombing of Domodedovo airport in Moscow, Russia, are fuelling interest in exploring new methods for keeping travellers safe. Low-tech alternatives may appeal to people who fear new full-body scanners are exposing them to harmful radiation and invading their privacy. “Animals’ noses are always a good solution, and the mice don’t see you naked,” says Bruce Schneier, who runs the blog Schneier on Security.

However, Schneier adds that there are drawbacks that could prevent their widespread use. For instance, their cages need regular cleaning, and new mice would have to be trained all the time because of their short working life. And while useful for explosives, they could never replace current baggage scanners and metal detectors.

Nonetheless, the company ran its first field test in December last year at Azrieli Center, a large shopping mall in Tel Aviv. More than 1000 people passed through the detector, 22 of whom were asked to hide mock explosives in pockets or under shirts. All 22 packages were detected, the Lumbrosos claim, adding that the false-alarm rate was less than 0.1 per cent.

Like a moth to an explosive Moths have an exquisite sense of smell, so their ability to sniff out improvised explosive devices was recently tested by Andrew Myrick and Tom Baker at Pennsylvania State University in University Park. The team built a detector using four live moths which were immobilised in thin, aerated tubes. Different chemicals produce distinct voltages on the antennae that the moths use to sense aromas, so the team wired up the moths to record these levels. Software inferred the explosive source’s direction and distance based on the strength of signals coming from the insects. The detector was then able to home in on it to within 20 centimetres from 23 metres away.