Richard Maynard
House mice and Norway rats are the two most common rodent problems in Hampton Roads homes and businesses. Both enter through gaps as small as a quarter inch, both breed year-round indoors, and both require professional exclusion work for lasting control.
Identification
How to Tell Mice from Rats
House mice are small — 12 to 20 cm including the tail — with large rounded ears relative to their head size, a pointed snout, and droppings about the size of a grain of rice (3 to 4 mm). Their fur is typically dusty gray or brown on top, lighter underneath. They are curious and will investigate new objects in their environment.
Norway rats are significantly larger — 32 to 46 cm including the tail — with small, close-set ears, a blunt snout, and droppings 18 to 20 mm long (roughly the size of a raisin). Their fur is coarse and brown to gray. They are cautious and neophobic — they will avoid new objects placed in their environment for several days, which affects trapping strategy.
Grease marks along baseboards and wall edges are a consistent sign of both species. Rodents have poor eyesight and run with their bodies in contact with walls and vertical surfaces, leaving oily smudge marks from their fur over time.
Behavior & Diet
Behavior and Biology
House mice are explorers. They establish small, overlapping territories of 10 to 30 feet and forage constantly. They gnaw on everything — food packaging, wood, electrical wiring, pipe insulation — for both nutrition and to control incisor growth. Their teeth grow continuously.
Norway rats are burrowers. They excavate burrow systems under decks, concrete slabs, compost bins, and building foundations. They are strong swimmers and common in areas near water — Norfolk, Portsmouth, Newport News, and the waterfront neighborhoods of Virginia Beach are high-risk areas. They are cautious, intelligent, and will learn to avoid trap patterns.
Both species breed year-round indoors. A house mouse produces 6 to 12 pups per litter with 6 to 8 litters per year. Norway rat females average 3 to 6 litters per year of 8 to 12 pups. An untreated house mouse infestation can go from 2 to 100 or more individuals in a single season.
Threats & Damage
Health Risks and Structural Damage
Rodents contaminate food and surfaces with droppings and urine carrying Salmonella, Leptospirosis, and Hantavirus. Hantavirus is transmitted by breathing in dust contaminated with the urine, droppings, or nesting material of infected deer mice — a species less common in urban Hampton Roads but present in wooded and rural areas of Chesapeake and Suffolk.
Rodent gnawing on electrical wiring is a significant fire risk. Rodents are implicated in an estimated 20 to 25 percent of fires with undetermined causes nationwide. They strip wire insulation, creating short circuit potential inside walls where the damage is invisible.
In crawl spaces, rodents damage vapor barriers, compress and contaminate insulation, and create entry points for secondary pests including cockroaches and flies that breed in rodent waste.
Prevention & Treatment
Prevention and Professional Exclusion
The permanent solution to rodent control is exclusion: physically sealing every entry point. A house mouse can fit through a gap the size of a dime. A rat can fit through a gap the size of a quarter. Common entry points include gaps around utility pipes at the foundation, cracks in the foundation itself, gaps at the band board (the board sitting on top of the foundation), damaged soffit and gable vents, and the gap between garage doors and the floor when door sweeps are missing or worn.
We use steel wool packed into gaps (rats cannot chew through it), hardware cloth secured over vent openings, expanding foam for foundation cracks, and door sweeps with metal reinforcement on the sweep edges.
Bait stations and snap traps eliminate the existing population. Exclusion keeps them from being replaced. Without exclusion, control is temporary. See our rodent control service page for our full Hampton Roads rodent elimination and exclusion program.