Rats have a reputation as pure pests, yet they do real, measurable good for people. Their most surprising talent is their nose, which trained rats put to work finding hidden dangers and diseases.1PubMed Central. Using trained pouched rats to detect land mines: another victory for operant conditioning Most of that good comes from specific rats in specific roles, though, not from the ones raiding your trash.
Rats That Find Landmines
Giant African pouched rats are used to find buried landmines in Mozambique.2PubMed Central. Using trained pouched rats to detect land mines: another victory for operant conditioning They have an excellent sense of smell, and they weigh too little to set off a mine.3PubMed Central. Using trained pouched rats to detect land mines: another victory for operant conditioning They are also native to sub-Saharan Africa, so they resist local parasites and diseases.4PubMed Central. Using trained pouched rats to detect land mines: another victory for operant conditioning
Training runs on reward. A rat hears a click at the moment it does the right thing, then gets food, typically a small treat. It learns to pause and scratch at the spot where it smells explosive. A handler marks that spot so human deminers can remove the device safely.
On a working day, the rat wears a lightweight harness clipped to a line held between two handlers. It walks along marked lanes, so the ground is covered in a systematic grid. Sessions are short and usually happen in the cooler part of the day, because the animals tire and the work needs steady concentration.
The results are strong. In one year, the rats searched 93,400 square metres and found 41 mines and 54 other explosives.5PubMed Central. Using trained pouched rats to detect land mines: another victory for operant conditioning People sweeping the same ground with metal detectors found no mines the rats had missed.6PubMed Central. Using trained pouched rats to detect land mines: another victory for operant conditioning The rats raised a false alarm only about once for every 300 square metres, within international accreditation limits.7PubMed Central. Using trained pouched rats to detect land mines: another victory for operant conditioning
Metal detectors beep at every nail, can, or shell fragment in the soil. A rat reacts to the explosive itself, not to harmless metal, so human teams make far fewer pointless digs.
Rats That Screen for Tuberculosis
Pouched rats can also be trained to smell tuberculosis (TB) in sputum, the mucus people cough up.8PubMed Central. Rats sniff out pulmonary tuberculosis from sputum: a diagnostic accuracy meta-analysis Across many trials, rats correctly flagged about 87 out of 100 positive samples, and they correctly cleared about 88 of 100 negative samples.9PubMed Central. Rats sniff out pulmonary tuberculosis from sputum: a diagnostic accuracy meta-analysis Judged per patient rather than per sample, they caught about 81 of 100 sick patients.10PubMed Central. Rats sniff out pulmonary tuberculosis from sputum: a diagnostic accuracy meta-analysis
In clinics, rats found more TB cases than the common microscope test.11PubMed. Accuracy of giant African pouched rats for diagnosing tuberculosis: comparison with culture and Xpert(®) MTB/RIF They also flagged many healthy people, wrongly calling more than half of negative samples positive.12PubMed. Accuracy of giant African pouched rats for diagnosing tuberculosis: comparison with culture and Xpert(®) MTB/RIF So rats work best as a quick first screen, followed by a lab test to confirm.13PubMed. Accuracy of giant African pouched rats for diagnosing tuberculosis: comparison with culture and Xpert(®) MTB/RIF The appeal is speed: a rat can check many samples faster than a technician at a microscope, which helps in poor regions with a lot of TB and few labs.
Rats in Rescue and Wildlife Protection
A nonprofit called APOPO is training rats to help find survivors under rubble after disasters.14KKTV. Rescue rats trained to search for disaster survivors Rats are small and agile enough to slip into narrow gaps that rescuers and dogs can’t reach.15Hürriyet Daily News. Backpack-wearing rats to search for survivors beneath rubble in Türkiye – Türkiye News Each rat wears a light backpack with a camera and GPS tracker so teams can follow it live.16Hürriyet Daily News. Backpack-wearing rats to search for survivors beneath rubble in Türkiye – Türkiye News When it smells a person, it pulls a trigger that rings a bell and signals rescuers outside.17Hürriyet Daily News. Backpack-wearing rats to search for survivors beneath rubble in Türkiye – Türkiye News Planned backpacks would add a microphone and speaker so rescuers can talk to a trapped survivor.18APOPO. Sniffing Out Survivors • APOPO
Training starts from the same reward idea as mine detection: the scent of a living human leads to a food treat. The rat must pull the trigger only for a person, not for other smells in rubble. The first rescue rat programs, such as one in Antalya, Türkiye, are just starting, and the hope is faster location of survivors in the first critical hours.
Rats can also learn to detect smuggled pangolin scales, rhino horn, elephant ivory, and a threatened African hardwood.19Frontiers in Conservation Science. Ratting on wildlife crime: training African giant pouched rats to detect illegally trafficked wildlife They ignored items smugglers commonly use to hide these goods.20Frontiers in Conservation Science. Ratting on wildlife crime: training African giant pouched rats to detect illegally trafficked wildlife So far this has been shown in lab tests, not at real ports. If it carries over, a rat could quickly check cargo samples before officers open anything, which matters because shipping containers are too many for people to search by hand.
Why Medicine Depends on Lab Rats
Rats have been among the most-used lab animals for well over a century.21PubMed Central. The Laboratory Rat: Relating Its Age With Human’s Their bodies, organs and genes are similar to ours in many ways.22PubMed Central. The Mighty Mouse: the impact of rodents on advances in biomedical research They are also small, easy to keep, and breed quickly, so studies run faster.23PubMed Central. The Mighty Mouse: the impact of rodents on advances in biomedical research Almost every human gene linked to disease has a counterpart in the rat.24University of Cambridge. Rats A counterpart means the rat has a version of that gene doing a related job, not an identical one.
Rat research has advanced treatments for heart disease, diabetes, wound healing, nerve repair and organ transplants.25University of Cambridge. Rats New drugs are widely tested on rats for safety and effectiveness before people take them.26University of Cambridge. Rats Rats are also used to study behaviour because they have larger brains than mice and are less timid.27University of Cambridge. Rats
Rats don’t think like humans, and many treatments that work in rats fail in people. That’s why human trials follow before a treatment is approved.
Rats also helped reveal how brains make maps. Studying them uncovered brain cells that track where an animal is and which way it faces.28PubMed. Spatial cognition in bats and rats: from sensory acquisition to multiscale maps and navigation In young rats, the direction-sensing cells appear first, before their eyes even open.29PubMed. The development of spatial and memory circuits in the rat
How Wild Rodents Help Forests and Soil
Rodents carry seeds away from parent trees and bury them in the soil.30PubMed. Bold rats (Niviventer confucianus) are more effective in seed dispersal: evidence both under enclosure conditions and in the field Forgotten stashes sprout, helping forests regrow.31PubMed. Bold rats (Niviventer confucianus) are more effective in seed dispersal: evidence both under enclosure conditions and in the field Bolder rats bury seeds in more scattered spots and carry them farther, making them better seed spreaders.32PubMed. Bold rats (Niviventer confucianus) are more effective in seed dispersal: evidence both under enclosure conditions and in the field Near forest edges, though, rodents move fewer seeds, which slows regrowth there.33Global Ecology and Conservation. Reduced rodent-mediated seed dispersal at forest edge hinders regeneration
Rodents bury seeds in many small stashes to save food for lean times. The animal cannot remember every stash, so some seeds stay in the soil, where burying also shelters them from being eaten or drying out.
Burrows work the soil too. At normal numbers, they let air into the ground and help it hold water.34Ecological Frontiers. Research progress on the impact of small rodent disturbance on grassland ecosystem Soil microbes become more active and nutrients cycle faster.35Ecological Frontiers. Research progress on the impact of small rodent disturbance on grassland ecosystem Droppings and dragged-in plant material add nitrogen and potassium.36Soil Science. Burrowing Through the Literature: The Impact of Soil-Disturbing Vertebrates on Physical and Chemical Properties of Soil When burrows get too dense, plants are stripped and soil erodes.37Ecological Frontiers. Research progress on the impact of small rodent disturbance on grassland ecosystem
Rodents are also food. Owls, hawks, snakes and foxes depend heavily on them. After fires in parts of Patagonia, introduced black rats became main prey for native predators.
Are City Rats Good for Anything
A few small upsides exist. Sewer rats eat food waste that could otherwise help clog pipes.38ExJet. Sewer Rats City rats also store lead from their surroundings in their liver and kidneys.39PubMed. Are soft tissues of urban rats good indicators of exposure to heavy metal pollution? A study conducted in one of the most polluted basins of Buenos Aires, Argentina Testing wild rats therefore gives a cheap, quick measure of lead pollution in a city, which can warn of health risks to people living in the same area.40PubMed. Wild rats as monitors of environmental lead contamination in the urban area of Milan, Italy A cluster of high readings points to places where people, especially children, may be exposed and where soil or dust testing is worth doing.
The downside is bigger. Black and brown rats have been spread by people far beyond their native range, so in many places they are invasive. In places like New South Wales, introduced predators and habitat loss have left only 8 of 28 native rodent species non-threatened.41Wildlife Research. Ecological attributes and conservation of native rodents in New South Wales On one island, clearing habitat helped black rats while native rats declined.42PubMed Central. Differential population responses of native and alien rodents to an invasive predator, habitat alteration and plant masting Rats near homes can also carry diseases and gnaw wiring and food stores.
Many countries have native rat species that are shy and rarely enter homes. The rats in buildings are almost always brown or black rats, so protecting native rodents doesn’t mean tolerating house rats.
At home, seal gaps and keep food and trash in sealed containers. Traps work, while poisons can also kill owls and pets that eat poisoned rats, and those predators help keep rodent numbers in check. A rat’s value elsewhere doesn’t make an indoor infestation safe.
Rats Are Smarter and Kinder Than You Think
Rats will free a trapped cagemate in distress.43PubMed Central. Helping a cagemate in need: empathy and pro-social behavior in rats They quickly learn to open a door to rescue a cagemate stuck in water, and they don’t bother opening it for a cagemate that isn’t distressed.44PubMed. Rats demonstrate helping behavior toward a soaked conspecific Most chose to help the soaked cagemate before taking a food reward.45PubMed. Rats demonstrate helping behavior toward a soaked conspecific Rats that had been soaked themselves learned to help faster.46PubMed. Rats demonstrate helping behavior toward a soaked conspecific Scientists call this empathy-like behaviour, because it is hard to know exactly what a rat feels.
Rats also make high-pitched calls when tickled, beyond human hearing.47PubMed Central. Rat 50 kHz calls reflect graded tickling-induced positive emotion The more calls they make, the more they seek out what they experienced during tickling, a sign of real enjoyment.48PubMed Central. Rat 50 kHz calls reflect graded tickling-induced positive emotion
Pet rats are domesticated brown rats, social and trainable. They do best in pairs or groups, can learn names and tricks, and enjoy gentle handling.
Using Natural Rat Control on Farms and Yards
Farmers are increasingly replacing rat poisons with natural methods like encouraging predators.49Journal of Pest Science. Biodiversity patterns of small mammals and their natural predators: implications for rodent pest management in agricultural systems Nest boxes in fields let barn owls and kestrels settle near crops.50PubMed. Avian predators as a biological control system of common vole (Microtus arvalis) populations in north-western Spain: experimental set-up and preliminary results In one study, kestrel numbers rose faster, and voles became one of their main prey.51PubMed. Avian predators as a biological control system of common vole (Microtus arvalis) populations in north-western Spain: experimental set-up and preliminary results
A box gives a barn owl or kestrel a safe place to raise young, and hunting pairs feeding chicks catch many rodents nearby. Predators need time to settle, so a new box may not make a difference in the first season. They help keep numbers down but rarely wipe out a rodent population, so they work best alongside tidy habitat.
Habitat matters as much. Rice farmers in Vietnam cut poison use by 75% by clearing burrows, weeds and straw piles and planting together.52PubMed. Ecologically based management of rodents in the real world: applied to a mixed agroecosystem in Vietnam Rat damage and crop yields stayed the same as with usual methods.53PubMed. Ecologically based management of rodents in the real world: applied to a mixed agroecosystem in Vietnam
At home, an owl box can help on larger rural properties. Removing woodpiles, debris and dense weeds takes away hiding places. Working with neighbours helps because rats move between properties.