What Are Rats?
Rats are a type of rodent that often live in cities. They are smart and extremely adaptable, which makes them hard to get rid of.
Rats can reproduce quickly. Female rats give birth to three to six litters of eight or more young each year. Young rats leave their mothers after 3 to 4 weeks and start having their own babies when they are around 3 to 5 months old. While pet rats can live longer, the average wild rat doesn't live for more than about a year.
Rats vs. mice
They're both rodents and have a lot in common, including that they may invade your home. The main way to tell the difference is that mice are a lot smaller than rats. Most mice you'll find in your house will be 2.5 inches to 3.7 inches long, not counting their tails. Even a small rat will usually be at least 5 inches long. Other differences include:
- Mice have ears that look big compared to their bodies, unlike rats.
- Rats are more likely to eat foods that are high in protein.
- Both reproduce quickly, but rats can have 1,000 offspring in a year, compared to several hundred for a single mouse.
- Rats are less territorial and more willing than mice to live in places with other rats.
How big do rats get?
Different species of rats grow to be different sizes. Norway rats, also called brown rats, are some of the largest pest rats. They can grow between 13 and 18 inches long and weigh between 7 and 10 ounces.
What do rats eat?
Rats are omnivores and will eat just about anything. They enjoy all types of human food, pet food, bird seed, garbage, compost, and even dog feces.
Are rats dangerous?
Rats can be one of the most dangerous pests. Rats spread more disease to humans than almost any other pest – second only to mosquitoes.
Do rats bite people?
The short answer is yes. Rat bites are more common than you might think. In the U.S., there are over 20,000 reported rat bites each year.
Always take rat bites seriously because rats can carry potentially deadly diseases. Their bites can spread harmful bacteria that cause rat-bite fever. If you're bitten, use soap and water to wash the wound, and contact your doctor right away.
Types of Rats
Around the world, you can find dozens of rat species. But you won't find most of those in your home or garden. If you have rats in your home, they're most likely one of two species.
Norway rats. With brown fur and gray bellies, these rats are larger, stockier, and have shorter tails than roof rats. They average about 13-18 inches long and weigh 7-10 ounces. Norway rats burrow beside building foundations, under garbage and wood piles, and around fields and gardens. Most Norway rats will keep to the basement or first floor when they move indoors.
Roof rats. Also called black rats or ship rats, roof rats have bellies that are gray or white and weigh between 5 and 10 ounces. Their tails are longer than their heads and bodies combined. They often nest in shrubs, trees, and other areas off the ground. Indoors, you can usually find roof rats in cabinets, ceilings, or attics.
Where Do Rats Live?
Norway rats live in every contiguous state of the U.S. Roof rats prefer warmer climates and can often be found along the coast.
Rats may live and nest in your house. You may also see them in your yard or garden. Norway rats are especially known for living near people. Gardens give them food, water, and a place to stay. You may see holes in the ground where rats are burrowing.
Health Risks of Rats
Rats can spread many diseases to both humans and animals, either directly or indirectly. Direct contact involves:
- Being bitten or scratched
- Eating contaminated food
- Touching contaminated objects or surfaces and then touching your eyes, nose, or mouth
- Breathing contaminated air
Indirect contact with rats usually happens when people or animals are bitten by fleas, mosquitoes, ticks, or mites that have bitten infected by rats.
Hantaviruses you can get from rats
A few significant diseases can be caused by inhaling the urine and feces of infected rats. Hantaviruses are a family of viruses spread by mice and rats, and different variants of hantavirus are carried by different rodent host species. “Old World” strains of hantavirus – those found in the Eastern Hemisphere – may cause diseases like hemorrhagic fever with renal syndrome. “New World” hantaviruses – those found in the Americas – may cause diseases like hantavirus pulmonary syndrome (HPS).
HPS is a severe respiratory disease with a mortality rate of 38%. Early symptoms of HPS include fever and muscle aches, especially in the back, hips, shoulders, and thighs. Early symptoms may also include:
- Belly pain
- Chills
- Diarrhea
- Dizziness
- Headaches
- Nausea
- Vomiting
About 4-10 days after early symptoms appear, late-stage symptoms of HPS begin, which often affect the respiratory system. Symptoms like coughing, shortness of breath, and fluid in the lungs are typical.
In the U.S., two types of rats carry hantaviruses. Cotton rats carry a strain of hantavirus called the Black Creek Canal virus. While they mostly live in overgrown areas of the Southeast, cotton rats have been found as far west as California and as far north as Nebraska. Rice rats carry the Bayou strain of hantavirus and are found in marshes from the Southeast to Texas and Pennsylvania.
Two species of mice also carry hantaviruses in the U.S. The white-footed mouse carries a strain called the New York virus. These mice live in wooded and brushy areas of the Midwest and southern New England. The tiny, wide-eyed deer mouse lives all throughout the U.S. and carries the Sin Nombre strain of hantavirus. The Sin Nombre virus is the most dangerous strain, with a mortality rate of 50%.
Other diseases spread by rat droppings
While a hantavirus may be the most devastating disease spread by rodent urine and feces, it is not the only one. Other diseases that are endemic to the U.S. and spread by rats or their droppings include:
- Leptospirosis. A bacteria that spreads through the body fluids of infected animals, leptospirosis is most often caused by exposure to contaminated water, but humans can also be infected through the mucous membranes or cuts in the skin. Symptoms vary widely and can include belly problems, chills, fever, jaundice, and headaches. But some infected people show no symptoms at all.
- Lymphocytic choriomeningitis (LCM). LCM is caused by exposure to the droppings, urine, or saliva of an infected rodent. While it is usually carried by the common house mouse, any rodent can become a carrier. The illness begins with flu-like symptoms but can get worse, causing encephalitis, meningitis, or meningoencephalitis. It's rarely fatal, but getting LCM during pregnancy can cause serious and permanent birth defects or even fetal death.
- Rat-bite fever (RBF). In North America, RBF is caused by the bacteria Streptobacillus moniliformis. The bacteria spreads through saliva via bites – as indicated by the common name – but can also spread through contact with the urine or feces of an infected rodent. RBF starts with flu-like symptoms but can quickly lead to infections throughout the body, which are fatal about 10% of the time.
Rats and the plague
Plague is perhaps the most well-known disease rats spread through indirect contact. Plague is a bacterial disease that killed millions of Europeans in the Middle Ages. In modern times, untreated plague can still cause serious illness or death. About seven cases of plague are reported in the U.S. each year, mostly in Western states.
Plague can take on three main forms:
Bubonic plague. Symptoms include fever, chills, headaches, weakness, and swollen lymph nodes.
Septicemic plague. Beginning with similar symptoms as bubonic plague, septicemic plague can get worse to cause internal bleeding and parts of the body, like the fingers, toes, or nose, to turn black and die.
Pneumonic plague. Along with a headache, fever, and weakness, pneumonia quickly develops, making it hard to breathe and causing chest pain, coughing, and sometimes watery or bloody mucus.
Signs You Have Rats
Unless you have many rats in your home, you could have rats and never see them. If you think you might have rats, there are several signs you can look for.
Some common signs of a rat infestation include:
- Rat droppings around your home, garage, or pet food dishes
- Chewed holes around your baseboards or door frames
- Burrows under garbage bins or in your yard, garden, or compost piles
- Rat nests behind boxes or inside sheltered spaces like wood piles or drawers
- Sounds like something is scratching or moving between the walls or in the attic
- Rats seen around your property or walking along fence tops or utility lines, often around dusk
Is It Rat Poop?
Rat droppings are typically easy to identify: black or dark brown pellets that are slightly larger than grains of rice. Mouse droppings look similar, but they’re much smaller. You will often find droppings in piles, and if you’ve found one, there are likely more because rats use their urine and droppings to mark trails for other rats to follow. When cleaning up rat messes, be very thorough – traces of urine or feces could leave an odor and attract more rats.
Is rat poop dangerous?
Rats are known to carry disease. They can have many types of bacteria and viruses within their bodies. They also attract disease-infested pests like fleas, which is how the bubonic plague, or Black Death, spread across 14th-century Europe. If you find rat poop, there's no need to panic. But you should take steps to carefully clean it up and get rid of any rats in your home.
How to clean up rat poop
Because contact with rat poop and pee can lead to dangerous and life-threatening infections, use extreme caution when cleaning. Inhaling particles from rat droppings can cause diseases like hantavirus, so be very careful not to clean up the droppings in a way that kicks up dust, like sweeping or vacuuming.
To lower your risk of infection, follow these steps when cleaning up rat urine and droppings:
- Wear rubber or plastic gloves. Consider a dust mask as well in case you accidentally kick up dust.
- Spray the area with a bleach solution or household disinfectant. The bleach solution should be 1.5 cups of household bleach in 1 gallon of water. If using a household cleaner, make sure the label reads “disinfectant.”
- Apply the cleaner liberally until the area is very wet, and let it sit for 5 minutes.
- Wipe up the urine and feces with a paper towel.
- Place the paper towel in a covered garbage can that is regularly emptied or a garbage bag you plan to dispose of right away.
- Mop or sponge the area again with the cleaning solution.
- Wash your gloved hands with soap and water before removing the gloves.
- Dispose of the gloves and wash your hands again.
If the rat poop seems recent, take steps to get rid of rats in your home. The longer rats are there, the greater your chances are of getting sick from them.
How to Get Rid of or Prevent Rats
To get rid of rats, there are several steps you can take:
Remove potential places for them to live. Clear out dense garden beds and shrubs, and keep garbage, compost, or wood piles away from your home.
Prevent access to food. Keep garbage, pet food, bird seed, and other possible food sources in galvanized cans with fitted lids. Remove any uneaten food from the dishes after feeding your pets.
Block entry points. Seal any cracks around your foundation, floors, doors, or windows that are wider than one-fourth of an inch.
Use scents rats don't like. Try repellents that have a smell like mothballs that rats don't like. Plant mint, lavender, or citronella, or scatter mint leaves, peppermint oil, or cinnamon around your house. Place cotton balls with vinegar where you see their nests.
Set traps. Rat traps come in a variety of lethal and nonlethal options. If you have Norway rats, put traps in dark areas close to the walls and any place you see droppings. If you have roof rats, place traps along ledges, shelves, beams, and tree branches.
Use rat poison. There are many types of rat poisons. Carefully follow all safety and usage directions for the product you choose. Rat poisons are toxic to humans, pets, and other animals. Avoid using them indoors, and keep them out of reach of children.
Call an exterminator. If you can't get rid of rats yourself or would rather someone else do it, call an exterminator. Search for companies in your area and ask them about their methods to make sure you are comfortable with them. While this is most likely to work, it's also the most costly option.
A word on getting rid of rats humanely
You can't humanely kill rats. So the best way to deal with them is to keep them out or try to make your yard and house less appealing to them. You should never use glue traps for any pest. Poisons you might use for rats also could kill foxes, owls, or hawks that eat rats. If you're going to use a kill trap, it's best to use a strong snap trap made from wood and metal, not plastic.
Killing rats with baking soda
You may have read you could use baking soda to kill rats. The idea is that the powder will react with their stomach acids in ways that will kill them. But this method is unlikely to work. If it did work, it would also be a slow and painful death. You could end up with dying rats hiding in your home where you can't find them. For all these reasons, this isn't a good way to try to get rid of rats in your home.