Are Brown Rats Dangerous? What You Need to Know

  • MickAdmin
  • March 26, 2023

Brown rats, also known as Norway rats, are common in cities and suburbs worldwide. They are notorious for their scavenging habits and ability to thrive in various environments. However, many wonder if these rodents are dangerous to humans and pets.

While brown rats are not typically aggressive toward humans, they can still be dangerous. They have known carriers of diseases such as leptospirosis, salmonella, and hantavirus. In addition, their droppings and urine can contaminate food and water sources, leading to further health risks.

Despite their potential dangers, brown rats are still valuable to the ecosystem. They help control insect and other pests’ populations and are an essential food source for many predators. However, individuals must prevent infestations and minimize contact with these rodents to reduce the risk of illness and disease.


Physical Characteristics of Brown Rats


Brown rats are also known as Norway rats or sewer rats. They are medium-sized rodents that can grow up to 10-12 inches long and weigh up to 1 pound. They have a long, pointed snout, small ears, and a thick, scaly tail shorter than their body length. Their fur is usually brown or grayish-brown, and they have lighter-colored bellies.

One of the most distinctive physical characteristics of brown rats is their teeth. They have a pair of large, curved incisors in their upper and lower jaws that never stop growing. They constantly gnaw on complex objects like wood, plastic, and metal to keep their teeth from getting too long.

Brown rats have excellent senses of hearing, smell, and touch. Their eyesight is not as good, but they can still detect movement and see well in low-light conditions. They are also agile climbers and can scale walls and trees with ease.

Overall, brown rats are well-adapted to living in various environments, from sewers and garbage dumps to fields and forests. In addition, their physical characteristics make them well-suited for scavenging and surviving in urban areas.


The behavior of Brown Rats


Brown rats, also known as Norway rats, are social animals that live in groups. They are active mainly at night and are excellent swimmers and climbers. Brown rats are also known for their intelligence and problem-solving abilities.

Brown rats are omnivores and will eat almost anything, including fruits, vegetables, grains, insects, and small animals. They are known to be opportunistic feeders and will scavenge through garbage to find food.

These rats are also known for their burrowing behavior. They create extensive burrow systems that can be found in fields, gardens, and even under buildings. These burrows can cause damage to structures and pose a threat to the stability of buildings and other infrastructure.

When threatened, brown rats can become aggressive and will bite. They also carry leptospirosis, hantavirus, and salmonella, which can be transmitted to humans through contact with their urine or feces. Therefore, taking precautions when dealing with brown rats, such as wearing gloves and avoiding direct contact with them is essential.

In summary, brown rats are social, intelligent, and opportunistic animals known for their burrowing behavior and ability to carry diseases. Therefore, taking precautions when dealing with these rats is essential to avoid the risk of disease transmission and structural damage.


Diseases Carried by Brown Rats


Brown rats carry various diseases that can be transmitted to humans. These diseases can be transmitted through contact with rat urine, feces, saliva, or bites. Below are some of the diseases that brown rats can carry:

  • Leptospirosis – a bacterial infection that can cause symptoms such as fever, headache, muscle aches, and vomiting. In severe cases, it can lead to organ failure and even death.
  • Hantavirus – a viral infection that can cause symptoms such as fever, muscle aches, and respiratory problems. In severe cases, it can lead to respiratory failure and death.
  • Salmonellosis – a bacterial infection that can cause symptoms such as diarrhea, fever, and abdominal cramps. It can be hazardous for young children, older adults, and those with weakened immune systems.
  • Plague – a bacterial infection that can cause symptoms such as fever, chills, and swollen lymph nodes. It can be transmitted to humans through flea bites from infected rats.

It is important to note that not all brown rats carry these diseases, and not all people who come into contact with rats will become sick. However, taking precautions to avoid contact with rats and their droppings and to seek medical attention if you suspect you have been exposed to a rat-borne disease is still essential.


Preventing Brown Rat Infestations


Preventing a brown rat infestation is much easier than trying to get rid of one. Here are some steps you can take to keep rats away from your home:

  • Seal all entry points: Brown rats can squeeze through holes as small as a quarter. So seal all entry points, including gaps around pipes, doors, and windows, with caulk, steel wool, or other materials.
  • Remove potential food sources: Rats are attracted to food. Store food in airtight containers, clean up spills, and dispose of garbage regularly.
  • Keep your home clean: Clutter and debris provide hiding places for rats. Keep your home clean and tidy, and remove any clutter or junk from your yard.
  • Trim trees and bushes: Rats can use trees and bushes to climb onto your roof and into your home. So keep trees and bushes trimmed away from your home.
  • Use rat traps: Rat traps can be an effective way to catch and kill rats. Place them where rats are likely to travel, such as along walls or dark corners.
  • Hire a professional pest control company: If you have a severe rat infestation, it’s best to call the professionals. They have the tools and expertise to get rid of rats quickly and safely.

These steps can significantly reduce the risk of a brown rat infestation in your home. Remember, prevention is critical when it comes to dealing with rats.




After reviewing the available information, it is clear that brown rats can pose a danger to humans in certain situations. While they are generally not aggressive towards people, they can carry diseases that can be transmitted to humans through contact with their urine, feces, or saliva.

Additionally, brown rats are known to cause damage to property and infrastructure, which can result in costly repairs. They can also chew through electrical wires, which can create a fire hazard.

However, it is essential to note that not all brown rats are dangerous, and many are harmless to humans. Some people keep pet rats as companions and find them friendly and intelligent animals.

Overall, it is essential to take precautions to avoid contact with wild rats and to keep your home and property clean and free of potential nesting sites. If you suspect a rat infestation, contacting a professional pest control service is best to handle the problem safely and effectively.

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