Roof Rats. How to Spot Them and Get Them Out

The tail gives it away. Pull a roof rat's tail over its back and it reaches at least to the snout. It is dark all over. A Norway rat's tail reaches only to the middle of the skull and is pale below.¹

Roof rats are smaller and sleeker, at 5 to 10 ounces, with a pointed muzzle, a gray to white belly and ears that reach the eyes when folded forward.¹ The roof rat is also called the black rat, house rat or ship rat. Its tail is longer than the head and body combined.¹

See the photos above, and compare with the Norway rat guide. Not sure it is a rat at all? Start at the mice and rats hub.

Roof rats breed fast, though not as fast as mice. The average number of litters is 3 to 5 a year, with up to 8 young in each.¹

They live where they nest. Roof rats usually nest above ground in shrubs, trees and dense vegetation such as ivy. Indoors they pick attics, wall voids, ceiling voids and cabinets. When no elevated place exists, they burrow into soil or live in sewers.¹

They roam far for food, up to 300 feet or more, so a roof rat may live in your landscaping and eat a neighbor's fruit.¹ That means your fix works only if the block works too.

Roof rats are easy to miss from the ground. Check overhead.

• Noises from the attic or drop ceilings.¹
• Rats running along utility lines or fence tops at dusk and after dark.¹
• Fruit or nuts with gnaw marks. Citrus gets hollowed out and left as an empty rind.¹
• Droppings near pet food and food storage.¹
• Roof rats climb, so look for gnawing high up on trim, vents and eaves.
• Nests in firewood stacks, garages and behind boxes.¹
• Smudge marks on beams and pipes where rats run.

Pet cats and dogs that drag in dead rats are another warning sign.¹

Rats contaminate food and gnaw buildings. UC IPM lists typhus, leptospirosis, rat bite fever and foodborne illness such as salmonella, E. coli and campylobacter among the diseases rats can transmit.¹

Plague is rarely found in roof and Norway rats, though it occurs in wild rodents in California. Roof and Norway rats do not carry or transmit rabies.¹

Rats are linked to medically significant allergic responses in people. They also destroy fruit crops and garden plants.¹

The biggest property risk is hidden. Rats living in an attic or wall void chew insulation and wiring unseen. Get an attic inspection before you decide the job is done.

Trap high, bait carefully. Snap traps are the safest, most effective and cheapest way to catch rats. For roof rats, set traps in off-the-ground spots such as ledges, shelves, branches, fences, pipes and overhead beams. Use about a pea-sized amount of bait. Space traps about 10 to 20 feet apart, and use a dozen or more in a heavy infestation. Keep traps away from children and pets.¹

Bait is tricky. Roof rats may not enter bait stations, even stations along established runways. Seal building entry points before outdoor baiting so poisoned rats do not die indoors.¹ EPA keeps second-generation poisons out of consumer products.³

Hire a pro for rats in the attic, repeated trap failure or a neighbor problem. Ask for the sealing plan in writing. See mice and rats for general trap steps.

A typical rat job costs $150 to $600, and about $400 for a 2,000 square foot home. A big infestation or large property can reach about $6,500.²

Sealing entry points runs $150 to $650, an initial inspection $90 to $150, and monthly visits $50 to $75. Fumigation is much higher at $2,000 to $6,500 or more.²

What moves the price? Where the rats live, whether they are in walls or crawl spaces, how much damage there is, and your region. Poorly maintained properties cost more.²

The page we used does not give a separate price for roof rats, so use the rat range and get at least two quotes.

Make the house hard to reach and boring to live in.

• Prune tree limbs that are within 3 feet of a roof.¹
• Remove climbing plants from buildings.¹
• Thin dense plantings and leave at least a 2 foot space between each shrub and between shrubs and buildings.¹
• Seal cracks and holes larger than 1/4 inch with steel wool, wire screen or sheet metal.¹
• Pick up fallen fruit and nuts and clean up garden debris.¹
• Feed pets only what they finish, or bring food inside at night.¹

UC IPM describes no off season for roof rats, so the grid shows steady activity where they live. They have 3 to 5 litters a year, so new rats arrive in every season.¹

What changes is where you see them. Fruit ripens, so trees draw rats at harvest. They also move indoors to attics and wall voids, which are enclosed, elevated spaces.¹

Prune and clean up fallen fruit before the main fruit season, and check the roofline twice a year.

Roof rats are a California and warm-climate pest. UC IPM says they prefer warm climates and coastal ecosystems.¹ The Ohio sources we used do not list roof rats as an Ohio home pest.

A rat in an Ohio attic or basement is most likely a Norway rat, since Norway rats live throughout the 48 contiguous states.¹ Check the tail against the photos above, then use the Norway rat guide.

Ohio law requires pest management companies to be licensed through the Ohio Department of Agriculture. Ask for the license, proof of insurance and workers' compensation, and get at least three bids.⁶

Roof rats are in almost all California cities, and their range is expanding. They like warm climates and coastal areas.¹ Mature landscaping, ivy and fruit trees make good habitat.¹

California limits poison. Three active ingredients are registered for rat control, bromethalin, cholecalciferol and zinc phosphide. Most first- and second-generation anticoagulants are prohibited for most uses, and bait used in and around structures generally must sit in bait stations within 50 feet of a structure.¹

Pest companies hold licenses by branch. Branch 2 covers household pests without fumigation. Applicators and field representatives can work only for a registered company.⁴ Verify a company or individual on the Board's online services page before you sign.⁵