(CNN) Buildings don't collapse very often -- but when they do, it's catastrophic for those trapped inside. Natural disasters like earthquakes and hurricanes can level entire towns, and for the search and rescue teams trying to find survivors, it's a painstaking task.
But an unlikely savior is being trained up to help out: rats.
The project, conceived of by Belgian non-profit APOPO, is kitting out rodents with tiny, high-tech backpacks to help first responders search for survivors among rubble in disaster zones.
"Rats are typically quite curious and like to explore -- and that is key for search and rescue," says Donna Kean, a behavioral research scientist and leader of the project.
In addition to their adventurous spirit, their small size and excellent sense of smell make rats perfect for locating things in tight spaces, says Kean.
The rats are currently being trained to find survivors in a simulated disaster zone. They must first locate the target person in an empty room, pull a switch on their vest that triggers a beeper, and then return to base, where they are rewarded with a treat.
While the rodents are still in the early stages of training, APOPO is collaborating with the Eindhoven University of Technology to develop a backpack, which is equipped with a video camera, two-way microphone, and location transmitter to help first responders communicate with survivors.
"Together with the backpack and the training, the rats are incredibly useful for search and rescue," says Kean.
APOPO has been training dogs and rats at its base in Tanzania in the scent detection of landmines and tuberculosis for over a decade. Its programs use African Giant Pouched Rats, which have a longer lifespan in captivity of around eight years compared to the four years of the common brown rat.
While the search and rescue project only officially launched in April 2021, when Kean joined the team, APOPO had been trying to get the idea off the ground for years but lacked funding and a search and rescue partner to support it. But when volunteer search and rescue organization GEA approached APOPO in 2017 about the possibility of using rats in its missions, the team began exploring the idea.
A key component to the search and rescue mission was the technology to allow first responders to communicate with victims via the rats. APOPO didn't have this -- until electrical engineer Sander Verdiesen got involved.
Looking to "apply technology to improve lives" during his master's studies at Eindhoven University of Technology, Verdiesen interned with APOPO in 2019 and was tasked with creating the first prototype of the rat backpack, to help rescuers get a better idea of what was going on inside disaster zones.
The prototype consisted of a 3D-printed plastic container with a video camera that sent live footage to a receiver module on a laptop, while also saving a high-quality version on an SD card. It attached to the rats with a neoprene vest, the same material that's used for scuba suits.
Verdiesen flew to Tanzania to test out the equipment and says that initially, the rats "didn't really know how to deal with it" but adapted quickly. "By the end, they were just running around with the backpack on, no problem at all," he adds.
With the backpacks working "better than expected," Verdiesen continued to refine the design even after his internship ended, as a volunteer.
But sizing down technology and adapting it for disaster zones hasn't been easy.
GPS can't penetrate the dense rubble and debris of collapsed buildings, says Verdeisen. An alternative is the Inertial Measurement Unit, a location tracker used in the heels of firefighters' boots.
"If you're walking, your foot is going to be still every step or so -- that's where you can recalibrate. With the rats, we're yet to find that," he says. Other engineers are working on similar projects, so he's hopeful they can find a solution.
Verdeisen is also trying to pack more technology into the next version, such as a two-way microphone, while reducing its size. Weighing around 140 grams (4.9 ounces), the prototype was twice as heavy as originally intended -- although Verdeisen says that bulkiness was more of an issue, at 10 centimeters long (3.9 inches) and 4 centimeters deep (1.6 inches).
"The rats were walking up against something that they would normally be able to go under, and suddenly they can't anymore," he explains.
To make it "as small as possible" without losing any functionality, Verdeisen plans to integrate everything onto a single printed circuit board, which will free up more space. This upgraded version of the backpack should be ready later this year, and he hopes one day it can help first responders "to locate somebody that would otherwise not be rescued."
Meanwhile, in Tanzania, Kean is increasing the complexity of the rats' training environment, "to make it more like what they might encounter in real life." That includes adding industrial sounds like drilling to mimic real emergencies.
So far, the results are promising: from her observations, Kean says the rats are responding well to the increasingly difficult simulations: "They have to be super confident in any environment, under any conditions, and that's something that these rats are naturally good at."
Handled from birth, the rats are exposed to a variety of environments, sights, sounds, and people as part of a "habituation process," which makes their gradual exposure to more extreme situations less stressful, according to Kean.
As animals are at the center of APOPO's projects and missions, welfare is a priority. The animals are trained in 15-minute sessions five days a week, and live alone or with same-sex siblings in home cages, which is also where they live out their days once they retire from working life.
Eating a diet of fresh fruit and vegetables, they also get daily playtime in a custom-built playroom -- although, for the search and rescue rats, training is very similar, "just with a little bit of direction," says Kean.
The program is still in development, but Kean estimates it will take at least nine to 12 months to train each rat.
For the next stage of training, Kean says the team will create "levels to mimic multiple floors of a collapsed building" and move closer to "real world scenarios." Once the rats are confident in more complex environments, the project will move to Turkey, where GEA is based, for further preparation in more realistic environments. If that goes well, then the rats would potentially enter real-life situations.
For now, though, Kean and the team in Tanzania are focused on getting the rats through their first phase of training -- and hopefully one day, into the field.
"Even if our rats find just one survivor at a debris site, I think we would be happy to know it's made a difference somewhere," says Kean.