Police, military, and security personnel have used dogs for years to locate explosives. In the last decade, homeland security and Middle East battlefronts have created an overwhelming demand for these four-legged finders that cannot always be met. Luckily, Mother Nature offers us a few other ways to detect things that go boom.

1. Bees

Bomb-sniffing dogs are great at their jobs, but they come with some drawbacks. It can take months to train a dog and his human handler, and keeping their skills sharp requires constant practice. Bomb dogs are also expensive, when you consider the costs of training, food, shelter, veterinary bills, and the salary of a dedicated handler. A UK company, Inscentinel, believes they have a cheaper, faster, but just as effective alternative: bees.

To train “sniffer bees," Inscentinel feeds the insects sugar water while exposing them to the smell of dynamite. After that, any time the bees detect dynamite, even in concentrations as small as a few parts-per-trillion, they'll extend their tongue-like proboscises, searching for a sugary treat. The training takes less than 10 minutes, but lasts for the bee's entire six-week lifespan. Although that is quite a bit shorter than the 10-year career of the average bomb dog, with these methods, Inscentinel can train about 500 bees a day, so there are always new sniffers ready to go.

Once the bees are trained, a few dozen are placed inside Inscentinel's handheld device, the Vasor136. Each bee is kept in place with a special bracket, and then monitored with an infrared sensor. If the sensors are set off by extended proboscises, an LCD screen alerts the human operator. Much like their six-legged partners, it only takes a few minutes to train a person to use the Vasor136.

With a quick training time, inexpensive food supply, and relatively cheap maintenance cost for a hive, bees can be a great alternative to bomb dogs. Best of all, in addition to bombs, bees can also be trained just as easily and quickly to sniff out illegal drugs or even some contagious diseases. And you thought they were only good for making honey.

2. Rats

Thanks to that whole Bubonic Plague thing, rats have gotten a pretty bad rap. But Bart Weetjens and his organization APOPO want to change all that with HeroRATS, a program that uses rats to safely and effectively clear minefields.

In case you're wondering, no, they don't just let the rats run across the minefield and see what happens. It typically requires at least 5kg/11lbs of weight to set off a mine, so even the African giant pouched rats used by APOPO, which weigh about 1.5kb/3.3lbs, can run through a minefield unharmed. To clear an area, the rats are accompanied by two human handlers who stand on either side of the danger zone with a wire running between them. The rat is tethered to the wire using a specially-designed harness, and the rodent runs back and forth across the area. If he stops to dig, it means he's detected the scent of dynamite. The mine is marked by a handler and the rat gets a piece of banana as a reward. With this technique, the team can clear a 300-square meter section of land in an hour. In comparison, two people using metal detectors would need two full days to cover the same area. Not only are the rats faster, but they can detect plastic-encased explosives that the metal detectors would miss.

Training HeroRATS takes about nine months at a cost of 6,000€/$7,400. But after that initial investment, they require very little medical care, are inexpensive to feed and shelter, and will live for up to eight years. In addition, they don't typically form tight bonds with specific handlers, a common occurrence with bomb dogs. This means that rats can easily work with any handler and still perform at a high level of accuracy.

Currently, APOPO operates in Mozambique and Thailand, with their headquarters and training facilities located in Tanzania. In addition to clearing minefields, the rats have also been used to detect tuberculosis, increasing the TB detection rates by 43% in partner hospitals. They’re also trying to train rats to enter debris left after an earthquake or other disaster to search for buried survivors.

The idea is catching on in America, too. Just a few weeks ago, the U.S. Army announced that it's working on a new program using bomb-detecting rats, called the Rugged Automated Training System (R.A.T.S.). Although they have no intention of replacing the military’s bomb-sniffing dogs, they’re looking at rats as a potential supplement animal to make bomb detection faster, cheaper, and more easily deployable to more units in the field.

3. Mice

An Israeli company, BioExplorers, is developing ways to train mice for use in public spaces like airport security gates, sports arenas, and even at drive-through toll booths to sniff out drugs or explosives. Similar to the handheld device from Inscentinel, the mice are housed inside an enclosure where they are monitored for signs of reaction to various scents. As a person walks past the enclosure, say just after they pass through the airport metal detector, the mice can get a whiff. If they react, the device beeps and red lights flash to warn a human operator. Training for one type of scent only takes about 10 days, with additional scents requiring a few additional days. But the mice can remember dozens of different scents, so they could become all-encompassing screeners in many different scenarios.

4 & 5. Dolphins and Sea Lions



Photo via the Official U.S. Navy Imagery Flickr account

Since the 1960s, the U.S. Navy has been training bottlenose dolphins and sea lions to detect and mark underwater mines. With the dolphins' underwater sonar capabilities, it’s been said they can detect the difference between a natural soybean and a man-made BB at a distance of up to 50 feet. When you consider that man-made sonar can’t differentiate between a rock and a mine, it’s pretty clear why dolphins are so useful in this capacity. Sea lions, on the other hand, use their excellent sense of sight – five times more powerful than man’s - to locate underwater mines. Once an explosive has been found, the animals point human handlers to the location by dropping an acoustic transponder or releasing a floating marker.

In addition to mines, the Navy’s dolphins and sea lions can also easily locate divers in places they shouldn’t be – say on the underside of a ship in a harbor. When an unauthorized swimmer is found, dolphins bump into the diver’s air tank and attach a strobe light connected to a buoy that floats to the surface so that sailors can apprehend the suspect. Similarly, sea lions clamp a special cuff around the diver’s leg. But instead of a strobe light, the cuff is attached to a line that runs back to a Navy ship, where the sailors aboard simply reel in the diver like the catch of the day.

Although the program has been around for decades, it wasn’t until the 1990s that it became declassified. Since then, the Navy’s dolphins have mainly worked and trained in the waters around their home port of San Diego. However, they have been deployed to patrol for unauthorized swimmers in Puget Sound in 2010, and in the Persian Gulf in 2003, where they helped clear more than 100 mines during the invasion of Iraq. Most recently, they have been considered for a mission in the Strait of Hormuz after repeated threats by Iran to block the Persian Gulf’s only sea passage.

6. Plants



Photo via the Colorado State University Department of Public Relations

With assistance from Professor June Medford of Colorado State University, future bomb sniffers might not even have noses. Medford and her team in the Biology Department have genetically modified plants’ natural receptors to air and soil pollutants to detect explosives and other dangerous chemicals. If these bomb-sniffing plants absorb TNT from the air, an internal switch is flipped and they change color from green to white. Once the TNT has been removed, the plants return to their natural color.

Bomb-sniffing plants could easily become an early warning device for everything ranging from explosives to chemical and biological weapons or even environmental pollutants. The plan is to eventually have certain types of plants set up to detect certain types of dangers. For example, if the hydrangeas planted outside the airport are white, but the roses are still red, you know you have a bomb in the area, but not anthrax. Medford is working to make the gene “plug-and-play”, meaning this new gene sequence could be used on virtually any type of plant, like trees. This would make it possible to use an airplane or satellite to monitor the leaves in a neighborhood to determine the breadth of an area affected by a pollutant.

As of right now, the color change takes place over a couple of hours. While that’s still a great early warning window, Medford hopes to speed that up to only a few minutes in the future.