Posted on August 15, 2025

For centuries, certain rodent species have lived alongside humans so successfully that they’ve earned a special name: commensal rodents. The word commensal means “sharing one’s table,” which is exactly what these pests do — survive and thrive by feeding on our food and sheltering in our spaces.

Here in Connecticut, the most common commensal rodent is the house mouse, followed by the Norway rat and roof rat. While many people think of mice as a small nuisance, the truth is they bring significant health risks, contaminate food, and can cause property damage. Even worse, our everyday sanitation habits — from overflowing trash bins to crumbs in the kitchen — make their lives easier and their populations grow faster.

1. What Are Commensal Rodents?

Commensal rodents are species that have adapted to live in close association with humans. They don’t just pass through — they actively depend on us for survival. The three primary types are:

House Mouse (Mus musculus)

Norway Rat (Rattus norvegicus)

Roof Rat (Rattus rattus)

These rodents have developed extraordinary survival skills in man-made environments, including squeezing through tiny gaps, chewing through packaging, and finding food in the most unlikely places.

2. The House Mouse: Small But Impactful

The house mouse is the most widespread commensal rodent in Connecticut. Measuring just 2.5–4 inches long (excluding the tail), it can fit through openings as small as a dime.

Key facts about mice:

Reproduction: A female mouse can have 6–10 litters a year, each with 5–12 pups. That’s up to 120 new mice annually from a single mother.

Behavior: Primarily nocturnal, but they will be active during the day if food is scarce.

Nesting: Often found in kitchens, attics, basements, behind appliances, storage boxes, and wall voids.

This rapid reproduction means that a small problem can become an infestation in just weeks.

3. How Humans Feed Mice Without Knowing It

Most rodent infestations are not caused by “dirty” people, but by accessible resources. Mice need only 3–4 grams of food per day — crumbs, grease buildup, or a few grains of pet kibble are enough to sustain them.

In homes, mice find food through:

Crumbs under appliances or furniture

Unsealed dry goods like cereal, rice, and flour

Pet food left out overnight

Overflowing indoor trash bins

In restaurants and food businesses, they thrive on:

Food scraps left on floors or prep areas

Grease buildup behind equipment

Open or unprotected food storage

Outdoor dumpsters with gaps or no lids

Outdoors, sanitation issues include:

Garbage cans without tight-fitting lids

Bird seed spills near feeders

Compost piles without rodent-proof enclosures

When food and shelter are consistently available, mouse populations can grow rapidly, often without being noticed until droppings, gnaw marks, or strange odors appear.

4. The Health Hazards of Mice

Many people don’t realize that mice can spread serious diseases — and some of them still exist in the United States today.

Health risks include:

Hantavirus – Spread through rodent urine, droppings, or saliva; can cause severe respiratory illness.

Plague – Caused by Yersinia pestis bacteria, still present in some rodent populations; transmitted via fleas.

Salmonellosis – Spread by consuming food or water contaminated with rodent droppings.

Asthma & Allergies – Rodent dander, droppings, and urine can trigger allergic reactions and breathing issues.

A hidden danger: Mice urinate constantly as they move, leaving behind invisible contamination trails on floors, counters, shelves, and food packaging. This means even one mouse can contaminate far more than it consumes.

5. Why Professional Rodent Control Matters

While store-bought traps and baits might catch a few mice, they rarely solve the underlying problem. Mice are fast breeders, and eliminating them requires addressing both the population and the conditions that sustain it.

KEA Pest Control uses Integrated Pest Management (IPM) to:

Inspect and identify entry points

Seal access gaps and cracks

Remove or reduce food and water sources

Apply targeted control methods for quick and lasting results

Provide ongoing prevention to stop re-infestations

6. Prevention Tips for Homes & Businesses

Seal any opening larger than ¼ inch around doors, windows, pipes, and foundations.

Store all food (including pet food) in airtight containers.

Empty trash daily and use sealed garbage bins.

Sweep and clean under appliances and furniture regularly.

Eliminate clutter where mice can nest.

For restaurants, implement nightly cleaning protocols and secure dumpster lids.

FAQ: Commensal Rodents & Mice

Q: Why are mice called “commensal rodents”?

A: Because they “share our table” — living alongside humans and feeding on our food waste.

Q: Can a single mouse make me sick?

A: Yes. Even one mouse can spread harmful bacteria and viruses through droppings, urine, and saliva.

Q: How do I know if I have more than one mouse?

A: Multiple droppings in different areas, gnaw marks, and nighttime scratching sounds usually indicate more than one.

Q: Do mice still carry the plague?

A: While rare, plague bacteria still exist in certain rodent populations in the U.S., particularly in the western states.

Q: What’s the fastest way to get rid of mice?

A: Professional pest control with exclusion, sanitation improvements, and targeted treatments is the most effective approach.

Protect Your Home or Business Today

Mice don’t need much to survive — but once they’ve moved in, they’re hard to evict without expert help. At KEA Pest Control, we combine proven rodent control strategies with eco-friendly methods to protect your family, customers, and property.

📞 Call 833-795-2714 or visit KEA Pest Control to schedule your rodent inspection today.