Cotton Rats

Facts, Identification, & Control

Latin Name

Sigmodon hispidus (Say & Ord)

Appearance

What Do They Look Like?

  • Size: The head and body of these pests range in length from 13.3 to 21.3 cm. Their tails are 7.6 to 16.5 cm in length.
  • Color: Cotton rats are usually gray on their back with black hairs mixed in. Their undersides are light in color.
  • Characteristics: Their bodies are covered with coarse hair. Their ears are almost hidden by the hair and their tails are bare with no fur.

How Did I Get Cotton Rats?

Leaving open bowls of pet food in yards and on porches can attract cotton rats. These pests may also enter homes through open holes in structures looking for food and shelter.

How Serious Are Cotton Rats?

Cotton rats are agricultural pests that may cause considerable damage to row crops. They live in grassy areas and feed on plants in crop fields and gardens. These rats are not usually structural pests, they can invade buildings, especially if they find food available.

These rats chew on grass and pile it up along soiled pathways. Yellow or greenish colored fecal pellets often build up near areas where these pests thrive that cause contamination.

Diseases
The hispid cotton rat is medically important because it is a host for hantavirus pulmonary syndrome (HPS). This disease can become airborne when rat droppings or carcasses are disturbed and people who inhale the airborne virus can become infected. These rats have also been found infected with plague and murine typhus.

Signs of Infestation

Possible signs of a cotton rat infestation include:

  • Droppings
  • Rodent sightings
  • Shallow burrows with multiple entrances

How Do I Get Rid of Cotton Rats?

What You Can Do
To discourage cotton rats, keep grass and weeds near all buildings mowed as short as possible. Seal up openings that might allow rats to enter. Since these rats can carry the virus for HPS, be very cautious when handling contaminated articles, dead rodents, and droppings.

What Orkin Does
Your local Orkin technician is trained to help manage cotton 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 cotton rats in their place and out of your home or business.


Behavior, Diet, & Habits

Nests
These nocturnal rats are active year-round, building nests both underground and above the surface. They move readily from fields into lawns and gardens, especially in suburban and rural areas. If the cotton rat population is very large and their nesting sites are located near a homeowner’s lawn, their movements can form runways in lawns that extend from nests to food sources.

Where Do They Live?
Cotton rats live in a wide variety of areas with heavy vegetative cover and where these areas are rarely, if ever flooded. They may at times inhabit overgrown ground cover around sidewalks or roadsides. These rodents are often found living in:

  • Barns
  • Brush along fence lines
  • Ditches
  • Gardens
  • Grassy fields
  • Hunting cabins
  • Lake homes
  • Storage sheds
  • Uncut grass

Geographical Range
Cotton rats are widespread across most of the country. Their range is from Florida to California and north to Virginia and Kansas. There have been reports of these rats as far north as Illinois.

What Do They Eat?
Cotton rat pests eat:

  • Eggs from ground-nesting birds
  • Grasses
  • Plants

Reproduction
Cotton rat infestations grow quickly due to the pests’ prolific rate of reproduction and begin breeding two or three months after being born. Populations can swell to over 140 rodents per acre. Females can produce as many as nine litters per year, with six young per litter. The young mature in about a month.

When there is plenty of food, these rats can reproduce at an amazing rate. But when food is scarce, their reproductive rate falls significantly.