Roof Rats

Facts, Identification, Control

Latin Name

Rattus rattus

Appearance

What Do They Look Like?

roof rat image
  • Size: These rats can be over 40 cm long. They are smaller and sleeker than Norway rats.
  • Color: Roof rats can be black or brown.
  • Characteristics: These rodents have long tails, large ears and eyes, and pointed noses. They have smooth fur with hairless, scaly tails that are longer than their heads and bodies.

How Did I Get Roof Rats?

Roof rats can fit through holes as small as one-half inch in diameter. Because they prefer to be high in the air, these rodents may climb on power lines or tree branches to get on the roof.

Entry Points
These rats have no problem reaching almost any area of the house, so many homeowners struggle to keep these pests out. These rodents often enter homes from:

  • Chewing entry holes
  • Damaged vent covers
  • Gaps in shingles
  • Squeezing through cracks

How Serious Are Roof Rats?

Roof rats can cause extensive and costly damage from:

  • Chewing on electrical wires
  • Damaging furniture and storage boxes
  • Ripping up insulation

Diseases
Roof rats spread diseases like salmonellosis through pantry foods contaminated with their droppings. These rats can also transmit rat bite fever through bacteria in their mouth. Trichinosis may be contracted through eating undercooked meat of animals that have fed on rats. Rats contaminating food or food preparation surfaces can transmit food poisoning.

Roof rats are the principle reservoir of plague throughout the world. Historically, infected fleas have transmitted serious plagues from rats to humans. Bubonic plague was a scourge in Europe several times throughout history. There are still outbreaks of plague in the United States and around the world today.

Hantavirus
Hantavirus pulmonary syndrome is transferred via inhalation of:

How Do They Transfer Diseases?
Common ways roof rats transmit diseases are from:

  • Bites
  • Contamination
  • Droppings
  • Fleas that feed on the rodents
  • Physical contact

Signs of Infestation

Droppings
Droppings are a good indicator of roof rat activity. Their droppings are 12 to 13 mm with pointed ends, whereas Norway rat droppings are 18 to 20 mm and capsule shaped.

Grease Marks
Grease marks along surfaces can be signs of an infestation. Grease marks are produced as the rodent travels along an edge, and the oils in their fur are deposited.

Visual Sightings
Sightings of live or dead rodents indicate rodent activity. If roof rats are seen exposed, it often indicates their hiding spaces are all filled by other rats or that they have been disturbed, such as by construction. You can find indoor nests constructed in insulation area including attics.

How Do I Get Rid of Roof Rats?

What You Can Do
Here’s how homeowners can help prevent roof rat infestations:

  • Block Entryways: To prevent a roof rats from nesting in your home, make sure that all windows and vents are screened.
  • Trim Trees: These rodents can get to the roof from the branches of trees. Trim all tree branches to further prevent entry.

What Orkin Does
Your local Orkin technician is trained to help manage roof rats and similar pests. Since every building or home is different, your Orkin technician will design a unique program for your situation.

Orkin can provide the right solution to keep roof rats in their place and out of your home or business.


Behavior, Diet, & Habits

What Do They Eat?
Roof rats are food hoarders, stashing supplies of food such as seeds and nuts. These rodents prefer to consume fruits (sometimes referred to as the “fruit rat” or “citrus rat”) and nuts, although roof rats are omnivorous and will feed on almost anything available to them. These rodents consume:

  • Fruits
  • Grains
  • Meats
  • Nuts
  • Tree bark
  • Seeds

Where Do They Live?
Roof rats are highly adaptable. They are nocturnal by nature and are accomplished climbers. They prefer to live in high places, but may live in a variety of environments if necessary. Their nests can be found in:

  • Attics
  • Buildings
  • Garage storage spaces
  • Piles of rubbish or wood
  • Rafters
  • Roofs
  • Trees
  • Wall voids

Reproduction
Roof rats become sexually mature between two and five months, producing four to six litters per year that consist of six to eight young each. The common lifespan of these rodents is about one year.

In dense populations, these rodents will establish a social hierarchy, wherein dominant males mate more than subordinate males. These rats are prodigious breeders and can breed year-round. Within a year, one female may be responsible for up to 40 new rodents.

Roof Rats & Disease Video