Rats
Rattus norvegicus / Rattus rattus
A commensal rodent that lives everywhere humans do.
Rats are intelligent commensal rodents that spread disease, contaminate food, and cause fire hazards by gnawing wiring.
At a glance
- Category
- rodent
- Seasonal activity
- Move indoors as temperatures drop; year-round in urban areas.
- Life cycle
- Females produce 3–12 litters per year with 6–12 pups each. Sexually mature at 5 weeks.
- Common locations
- Attics · Crawlspaces · Sewers · Garages · Behind walls
- Also known as
- Norway rat, roof rat
Entity relationships
Parent entity
Child entities
Related entities
Key attributes
Risk profile
A quick read on how this pest scores across the four factors that matter most.
- Health risk
- High
- Property damage
- High
- Spread potential
- High
- Treatment difficulty
- High
Seasonal activity
When this pest is most active across the calendar year.
Identification & habitat
Confirm what you're dealing with before choosing a treatment path.
How to identify
- Body 7–10" plus tail
- Capsule-shaped droppings 1/2–3/4"
- Grease rub marks along wall runways
- Gnaw marks on wood, pipe, and wire
Where they live
- Attics (roof rat)
- Basements and burrows (Norway)
- Sewers
- Garages
- Wall voids
Signs of infestation
- Dark, capsule-shaped droppings
- Gnaw marks on wood and wire
- Grease rub marks along walls
- Nighttime scratching in walls or attic
Diet
- Grains, meat, garbage, pet food
Behavior
- Neophobic — avoid new objects for days
- Follow the same runways nightly
- Family colonies of 8–15
Reproduction
Sexually mature at 5 weeks; a single pair can theoretically produce 15,000 descendants a year.
Life cycle timeline
Every treatment plan must reach every stage — miss one, and the population rebuilds.
- Stage 10–3 weeks
Newborn
Blind and dependent on mother.
- Stage 23–5 weeks
Weaned
Begins foraging with the colony.
- Stage 31–3 years
Adult
Sexually mature; reproduces continuously.
Health risks
- Leptospirosis
- Hantavirus
- Salmonella
- Rat-bite fever
Property damage
- Gnawed electrical wiring (fire risk)
- Contaminated insulation
- Structural damage from gnawing
Inspection checklist
- Attic walk — check insulation, tunnels, and droppings
- Exterior scan — utility penetrations, weep holes, vents
- Rooftop check for tree branches within 6 ft
- Garage — inspect door bottoms and stored boxes
Professional treatment
The proven, licensed protocol our specialists use in the field.
- 1
Exterior exclusion
Steel mesh and hardware cloth on every entry >1/2".
- 2
Interior trapping
Snap traps set along runways with pre-baiting to overcome neophobia.
- 3
Tamper-resistant bait stations
Exterior stations reduce reinfestation pressure.
- 4
Sanitation and clean-out
Remove contaminated insulation and disinfect.
You can handle
- Steel wool + sealant for very small gaps
- Snap traps in low-traffic garages
Get professional help
- Any activity in attic or wall voids
- Recurring infestations
- Contaminated insulation
What changes the price
- Structural sealing scope
- Attic remediation
- Number of bait stations
- Follow-up frequency
Prevention
Small habits keep rats from coming back after treatment.
Prevent rats
- Seal every opening larger than 1/2 inch
- Trim tree branches away from roof
- Secure trash and pet food
- Eliminate clutter in garages and sheds
Commonly confused with
Quick tells to separate rats from lookalikes.
vs. Mice
Mice are much smaller (2–4") with pointed muzzles and pinhead droppings.
Common myths
Bad advice makes infestations worse — here's the truth.
Poison alone solves rat problems.
Bait without exclusion just kills a portion of a rebuilding population.
Ultrasonic repellers work.
Peer-reviewed studies consistently show no lasting effect on rat behavior.
Frequently asked
Answers to the questions homeowners ask most about rats.
Are rat diseases really a concern?
Yes — leptospirosis, hantavirus, salmonella, and rat-bite fever are documented US infections.
Will they leave on their own?
No. A stable food and shelter source keeps colonies breeding year-round.
How long to eliminate a rat problem?
Trapping + exclusion typically resolves in 2–4 weeks; full attic remediation adds time.
Call a pro immediately if…
- Scratching in walls or ceiling
- Droppings in attic or garage
- Chewed wiring or plumbing
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