Mice and Rats: Facts, History and How to Keep Them Out of Your Home

Mice and rats often cause fear or disgust, but these small rodents have a surprising history. They have lived alongside humans for thousands of years, traveled the world on ships, played a role in major historical events and contributed to many scientific and medical discoveries. At the same time, wild rodents can spread diseases and damage homes, so it's important to know how to prevent infestations safely.

Mice vs. rats

Although people often confuse them, mice and rats are different species:

House mouse (Mus musculus): small, usually 7 to 10 centimeters long without the tail, with large ears, a pointed nose and a thin tail.
Brown rat (Rattus norvegicus): much larger and heavier, with a blunt nose, small ears and a thick tail. Also called the Norway rat, it often lives in sewers, basements and burrows.
Black rat (Rattus rattus): slimmer, with large ears and a long tail; an excellent climber, also known as the roof rat.

Signs of their presence include droppings, gnaw marks, nests made of shredded material, scratching noises and greasy marks along walls.

Rodents in history

Rodents spread around the world by traveling with humans on ships and caravans. The black rat is historically associated with the spread of plague, including the Black Death in the 14th century, which killed a large share of Europe's population. The plague bacterium was carried by fleas on rats. Recent research suggests that human fleas and lice may also have played an important role in its spread.

Rats also traveled with explorers and colonists, reaching islands where they affected native birds and other wildlife, a problem conservationists still work to solve today.

Remarkable abilities

Squeezing through small gaps: mice can pass through openings about the size of a pencil's width, and rats through slightly larger gaps.
Strong teeth: their incisors grow continuously, and they gnaw to keep them worn down, which is why they can damage wood, plastic and wires.
Agility: rats can climb, swim and jump.
Intelligence: rats can learn mazes, recognize patterns and solve problems.
Social behavior: they live in groups and communicate with sounds, some beyond human hearing.
"Laughter": researchers have described ultrasonic vocalizations that rats make during play and when tickled.

Rodents in science

Laboratory mice and rats are among the most important animals in biomedical research. Mice share most of their genes with humans, and their short life cycles allow scientists to study genetics, diseases and treatments. Research involving rodents contributed to advances in vaccines, cancer treatment, neuroscience and many other fields. This research is regulated to protect animal welfare, and scientists follow principles to reduce, refine and replace animal use when possible.

Rats that save lives

African giant pouched rats are trained by organizations to detect landmines and tuberculosis, thanks to their excellent sense of smell. They are light enough not to trigger mines. One of these rats, named Magawa, became famous for finding dozens of landmines in Cambodia and received a gold medal for animal bravery from a British veterinary charity in 2020.

Rodents in culture

In the Chinese zodiac, the rat is the first of the twelve animals, associated with intelligence and resourcefulness.
Mickey Mouse first appeared in "Steamboat Willie" in 1928, one of the most famous animated films in history.
Rodents appear in fables, literature and films, sometimes as villains and sometimes as clever heroes.

Health risks

Wild rodents can spread diseases through droppings, urine, saliva and bites, and by contaminating food. Examples include:

Hantavirus: in the Americas, transmitted mainly by breathing particles from droppings and urine of infected wild rodents, such as deer mice.
Leptospirosis: spread through water or soil contaminated with rodent urine, a particular risk during floods.
Salmonellosis: from contaminated food.
Rat-bite fever: a bacterial infection from bites or scratches.

Rodents can also damage electrical wiring, increasing the risk of fires, and contaminate stored food.

How to keep rodents out of your home

Seal entry points: fill holes and gaps in walls, floors, foundations and around pipes with steel wool, metal mesh or sealant.
Store food properly: keep food, including pet food, in sealed containers.
Manage trash: use bins with tight lids and take garbage out regularly.
Reduce clutter: remove places where rodents can hide and nest.
Maintain the yard: trim vegetation near the house, store firewood away from walls and remove fallen fruit.
Fix leaks: rodents need water.

Dealing with an infestation

Snap traps placed along walls are effective for small problems. Use poisons with great caution, since they can harm children, pets and wildlife; many experts recommend leaving them to professionals. For large or persistent infestations, contact a licensed pest control professional.

Cleaning safely

The CDC recommends not sweeping or vacuuming rodent droppings, which can spread particles into the air. Instead:

Ventilate the area for at least 30 minutes.
Wear rubber or plastic gloves.
Spray droppings and urine with a disinfectant or a bleach solution and let it soak.
Wipe up with paper towels and dispose of them in a sealed bag.
Disinfect the area again and wash your hands thoroughly.

Pet rodents

Pet mice and rats bred in captivity can be friendly, intelligent and affectionate companions. Pet rats can learn their names and tricks. They need spacious, clean cages, proper food, enrichment such as toys and tunnels, social companions of the same species and veterinary care.

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Frequently asked questions

What is the difference between a mouse and a rat?

Rats are much larger, with thicker tails and blunter noses. Mice are small, with large ears and thin tails.

Are mice dangerous?

Wild mice can spread diseases and contaminate food, so infestations should be controlled.

How do I clean mouse droppings safely?

Ventilate, wear gloves, spray them with disinfectant, wait and wipe them up. Don't sweep or vacuum them dry.

Can rats really detect landmines?

Yes. Trained African giant pouched rats help locate landmines in several countries.

How small a hole can a mouse fit through?

Mice can squeeze through very small openings, about the width of a pencil.

Do pet rats make good pets?

Yes, for many people. They are social and intelligent but need space, companionship and care.

Conclusion

Mice and rats are small animals with a big role in history, science and culture. By understanding them and taking simple prevention and cleaning steps, we can avoid health risks at home and appreciate these rodents from a new perspective.