Common Rodents Found in Long Island Homes & Businesses

Rodents are one of the most common pests found in Long Island homes and businesses. Mice, rats, squirrels, and chipmunks can all create problems, but the most serious issues usually happen when rodents enter structures, nest in hidden areas, or damage property.

Once inside, rodents can contaminate food, damage insulation and wiring, and leave droppings in kitchens, basements, garages, attics, and storage areas. Understanding the most common rodent species found in Nassau County and Suffolk County can help homeowners recognize early warning signs and know when a rodent problem needs attention.

House Mouse

The House Mouse is the most common rodent found in Long Island homes and commercial properties. Because they reproduce quickly and can fit through openings as small as 1/4 inch, a small mouse problem can become a larger infestation if the source isn't addressed.

• Appearance: Small, slender body (2.5 to 3.5 inches long, excluding the tail). Typically light brown or gray with a cream-colored belly, large ears, and a pointed snout.
• Behavior: House mice are curious, active breeders capable of producing multiple litters each year. They are excellent climbers and often travel along walls, utility lines, and other protected areas. Their droppings are small, dark, and rod-shaped.
• Signs of Activity: Homeowners often notice droppings in cabinets, pantries, garages, or basements. Other common signs include scratching sounds in walls or ceilings, gnaw marks on food packaging, and nesting materials such as shredded paper, cardboard, or insulation.
• Location: House mice typically nest in secluded indoor areas close to food and shelter, including wall voids, attics, cabinets, basements, garages, and storage rooms.

Deer Mouse

Often mistaken for the House Mouse, the Deer Mouse is primarily a woodland species but will enter homes, sheds, garages, and other structures, especially during the fall and winter. While less common indoors than house mice, they are an important rodent to identify because they can carry diseases that pose health risks to people.

• Appearance: Reddish-brown to grayish-brown fur with a distinct white belly and white feet. Deer mice have large ears, prominent dark eyes, and a sharply defined color contrast between the upper and lower portions of their body.
• Behavior: Excellent climbers and jumpers. Unlike house mice, deer mice commonly store seeds, nuts, and other food items near their nesting areas. They are primarily nocturnal and tend to avoid heavily populated indoor areas when suitable outdoor habitat is available.
• Signs of Activity: Homeowners may find small droppings in attics, garages, sheds, crawl spaces, or seasonal homes. Nesting materials, stored seeds, and scratching sounds in less frequently used areas of a structure can also indicate deer mouse activity.
• Location: Primarily found outdoors in wooded areas, brush, fields, and properties bordering natural habitats. During cooler weather, they may enter attics, wall voids, sheds, garages, and other sheltered areas to nest and escape the cold.

Norway Rat

Also known as the brown rat, the Norway Rat is one of the most common rat species found on Long Island. Their larger size, burrowing habits, and ability to travel long distances in search of food make them a serious concern for homes, businesses, restaurants, and multi-family properties.

• Appearance: Large, heavy-bodied rat measuring approximately 7 to 9.5 inches long, excluding the tail. They have shaggy brown or grayish-brown fur, a blunt nose, small ears, and a thick tail that is shorter than the length of their body.
• Behavior: Norway rats are primarily ground-dwelling rodents that create burrow systems beneath foundations, sidewalks, sheds, decks, and other structures. They are strong swimmers, excellent diggers, and constantly gnaw on materials to keep their teeth worn down, which can result in damage to wood, pipes, insulation, and electrical wiring.
• Signs of Activity: Homeowners may notice large capsule-shaped droppings, gnaw marks, burrow openings near foundations, grease marks along walls, or scratching sounds coming from lower levels of a structure. Outdoor rat activity is often first noticed around garbage areas, sheds, fences, and dense vegetation.
• Location: Norway rats commonly nest in outdoor burrows, crawl spaces, utility tunnels, and lower levels of structures. They are frequently found near food sources and can enter buildings through gaps around foundations, utility penetrations, garage doors, and damaged exterior openings.

Eastern Gray Squirrel

While generally considered wildlife, the Eastern Gray Squirrel is one of the most common nuisance rodents found on Long Island. Although they're most often seen outdoors, squirrels frequently enter attics, soffits, and wall voids where they can cause damage and create ongoing noise issues.

• Appearance: Gray fur with a white underside and a large, bushy tail. Adult squirrels typically measure 16 to 20 inches in total length, including the tail, and are much larger than mice or rats.
• Behavior: Squirrels are active during the day and are excellent climbers. They commonly chew on soffits, fascia boards, roof edges, and vents to gain access to attics. Once inside, they may build nests, damage insulation, and gnaw on electrical wiring.
• Signs of Activity: Homeowners often hear running, scratching, or rolling sounds coming from the attic during the daytime. Other signs include chewed roof vents, damaged soffits, nesting materials in attics, and squirrels regularly entering or exiting the same area of the roof.
• Location: Commonly found in trees, parks, and residential neighborhoods throughout Long Island. When they become a pest problem, they are most often found nesting in attics, wall voids, soffits, and other elevated areas of homes and buildings.

Eastern Chipmunk

The Eastern Chipmunk is a small ground-dwelling rodent commonly found throughout Long Island. While often viewed as harmless wildlife, chipmunks can become a nuisance when their burrowing activity occurs near foundations, patios, walkways, retaining walls, and other structures.

• Appearance: Small rodent with reddish-brown fur and distinctive dark and light stripes running along its back and face. Chipmunks are easily identified by their striped appearance and expandable cheek pouches used for carrying food.
• Behavior: Chipmunks are active during the day and spend much of their time collecting and storing food. They create extensive underground tunnel systems with multiple entrances and may establish burrows beneath patios, steps, decks, sheds, and other structures.
• Signs of Activity: Homeowners often notice small burrow openings near foundations, sidewalks, patios, retaining walls, or landscaping. Other signs include disturbed mulch, scattered soil around tunnel entrances, and chipmunks repeatedly entering and exiting the same areas of the yard.
• Location: Commonly found in yards, gardens, wooded areas, and landscaped properties throughout Long Island. They frequently establish burrows beneath decks, walkways, patios, stairs, retaining walls, and foundation areas where soil is easy to excavate.

Which Rodents Are Most Likely to Enter Long Island Homes?

While several rodent species live throughout Long Island, some are far more likely to become a problem inside homes and businesses than others.

• House Mouse – The most common indoor rodent on Long Island. House mice can squeeze through openings as small as a dime and often nest in walls, attics, basements, garages, and storage areas.
• Norway Rat – Common around foundations, crawl spaces, burrows, dumpsters, and sewer systems. Norway rats may enter homes and businesses while searching for food, water, and shelter.
• Deer Mouse – More common near wooded areas and properties bordering parks or open space. Deer mice may enter sheds, garages, crawl spaces, and homes during colder weather.
• Eastern Gray Squirrel – Often enters attics by chewing through roof edges, soffits, vents, and other vulnerable areas of the structure.
• Eastern Chipmunk – Usually remains outdoors but may cause property damage through burrowing around patios, walkways, retaining walls, and foundations.

If you're finding droppings, hearing scratching sounds, or noticing signs of rodent activity, identifying the species involved can help determine the most effective control and prevention strategy.

How Dangerous are Rodents?

Rodents can cause serious problems when they enter homes or businesses. Mice and rats constantly gnaw on materials to keep their teeth trimmed, which can damage insulation, wood framing, and even electrical wiring.

Rodents can also contaminate food and surfaces with droppings and urine. Some species are associated with diseases such as salmonella, hantavirus, leptospirosis, and other pathogens that can pose health risks if infestations are not addressed promptly.