Do Rodents Bite?

Rodents are generally shy and avoid humans, but they will bite in specific circumstances, usually when they feel threatened, cornered, or are protecting food or young. Here are some of the situations in which rodents are most likely to bite:

Defensive Reactions: Rodents, especially rats and mice, may bite if they feel trapped or startled. This often happens when someone tries to pick them up or corner them. Even a pet rodent that is normally friendly can bite if it feels threatened.
Handling by Humans: Improper handling or rough treatment increases the likelihood of a bite. For example, grabbing a mouse by the tail or picking up a rat too abruptly can provoke a defensive bite.
Protecting Offspring: Female rodents with young (pups or kits) are more likely to bite if they perceive a threat to their offspring. This protective instinct is strong and can override their natural fear of humans.
Food-Related Aggression: Rodents may bite if food is involved, especially if they are hungry or feel the food is being threatened. Rats, in particular, can become aggressive when hoarding or defending resources.
In a Confinement Situation: Rodents trapped in enclosed spaces, cages, or infested areas where they cannot escape are more prone to bite. Stress and fear in these situations increase aggressive behavior.
Disease or Injury: Sick or injured rodents may bite more readily because they feel vulnerable and stressed. For instance, a rodent carrying a disease or with dental issues may act unpredictably.
Wild Rodents Encountered Indoors: Wild rats or mice entering homes, basements, or attics may bite if they are cornered by humans or pets. Unlike domesticated rodents, wild rodents are less accustomed to human interaction and more likely to defend themselves.

Never attempt to handle wild rodents with bare hands. Use gloves, traps, or hire our professional pest control for rodents in homes or businesses. Rodent bites can transmit diseases such as rat-bite fever, leptospirosis, or hantavirus, so bites should be treated seriously.

Rodent Bites

Rodent bites can be more than just painful—they carry a range of potential health risks because rodents are carriers of various bacteria and viruses:

Bacterial Infections

Rodent mouths harbor bacteria that can cause serious infections if they break the skin. Common infections include:

Rat-bite fever (RBF): Caused by Streptobacillus moniliformis (more common in the U.S.) or Spirillum minus (more common in Asia). Symptoms: Fever, rash, vomiting, joint pain. Can be severe or even life-threatening if untreated.
Tetanus: Rodent bites can introduce Clostridium tetani into the wound, especially if it’s punctured deeply. Symptoms: Muscle stiffness and spasms. Particularly dangerous for people who are not up-to-date on tetanus vaccinations.
Secondary bacterial infections: Wounds from rodent bites can become infected with Staphylococcus or Streptococcus species. Symptoms: Redness, swelling, pus, pain, and warmth at the bite site.

Viral Infections

Though less common than bacterial infections, some viruses can be transmitted indirectly:

Hantavirus: Not always transmitted through a bite. Can be transmitted via contact with rodent urine, feces, or saliva. Severe cases can lead to Hantavirus Pulmonary Syndrome (HPS).
Lymphocytic choriomeningitis virus (LCMV): Can be transmitted by contact with rodent excretions. Rarely, bites from infected rodents may pose a risk.

Allergic Reactions

Some individuals may experience allergic reactions to rodent saliva or the proteins in their bite, ranging from mild itching and redness to more severe reactions like swelling.

Wound Complications

Delayed or improper cleaning of a rodent bite increases the risk of cellulitis (skin infection) or abscess formation.
Rodent bites are often puncture wounds, which close quickly and trap bacteria inside, making infections more likely.

What Do Rodent Bites Look Like?

Rodent bites have some characteristic features that can help identify them:

Appearance of the Bite

Puncture Marks: Rodent bites usually leave two small puncture wounds, often close together, caused by the rodent’s sharp incisors.
Size: The punctures are typically 1–3 mm apart, depending on the size of the rodent. Larger rats leave wider spacing, while mice have closer punctures.
Shape: The punctures are round or oval, sometimes slightly irregular if the rodent shakes its head during the bite.

Surrounding Skin Changes

Redness (erythema): The area around the bite is often red and inflamed.
Swelling: Mild to moderate swelling is common, especially if the bite breaks the skin deeply.
Bruising: Sometimes slight bruising occurs if the bite was forceful.

Secondary Effects

Pain: Rodent bites can be painful immediately and may continue to throb afterward.
Bleeding: Small amounts of bleeding are typical, especially with deeper punctures.
Pus or Discharge: If the bite becomes infected, it may produce pus, have an unpleasant odor, and the surrounding skin can feel warm to the touch.
Red Streaks: In cases of bacterial infection, red streaks may radiate from the bite (a sign of lymphangitis).

Additional Indicators

Multiple Bites: Rodents, especially when cornered, may bite several times in quick succession, leaving multiple paired punctures.
Location: Common bite locations are hands, fingers, feet, or forearms, especially when people try to handle or remove rodents.

Even a small rodent bite should be taken seriously due to infection risk. If the skin is broken, the bite should be cleaned immediately, and medical attention should be sought, particularly if there are signs of infection, fever, or if the bite was from a wild rodent.

What To Do About Rodent Bites

If you get bitten by a rodent, prompt and proper care is essential because rodent bites can easily become infected. Here’s what to do:

Immediate First Aid

Wash the wound thoroughly: Use warm running water and soap. Scrub gently but thoroughly for at least 10–15 minutes to remove dirt and bacteria.
Stop the bleeding: Apply gentle pressure with a clean cloth or sterile gauze until bleeding stops.
Disinfect the bite: Use an antiseptic such as iodine, hydrogen peroxide, or alcohol to clean the wound.
Protect the wound: Cover with a sterile bandage or gauze to prevent further contamination. Change the dressing daily or if it becomes wet or dirty.

Monitor for Infection

Rodent bites can become infected quickly. Watch for:

Redness, warmth, or swelling around the bite
Pus or foul-smelling discharge
Increasing pain or tenderness
Red streaks extending from the wound
Fever or flu-like symptoms

If any of these occur, seek medical attention immediately.

Seek Medical Care When

The bite is deep, punctured, or on the hand, face, or near joints
You haven’t had a tetanus booster in the last 5 years
The bite is from a wild rodent (risk of rat-bite fever or other zoonotic diseases)
Signs of infection develop

Reduce Risk of Complications

Avoid squeezing or handling wild rodents.
Keep pets away from rodents, as bites can occur indirectly.
Maintain good hygiene, especially if cleaning areas where rodents live.

Follow-Up

Continue to watch the wound for at least 1–2 weeks.
Seek follow-up care if swelling, redness, or fever persists.