Cotton Rats

Facts, Identification & Control

Latin Name

Sigmodon hispidus (Say & Ord)

Appearance

The head and body of cotton rats range in length from 13.3 to 21.3 cm. The tail is bare and is not as long as the head and body (7.6 to 16.5 cm). Their bodies are covered with coarse hair. The ears are almost hidden by the hair. The rats are usually gray on their back with black hairs mixed in. The underside is light colored.

Behavior, Diet & Habits

This rat is widespread across much of the country. Its range is from Florida to California and north to Virginia and Kansas. There have been reports of this rat as far north as Illinois.

Cotton rats are agricultural pests. They live in grassy areas and feed on plants. In some areas they have caused considerable damage to row crops. Cotton rats nest on the ground or in shallow burrows. They make trails in the grass where they travel.

Cotton rats move readily from fields into lawns and gardens, especially in suburban and rural areas. Although cotton rats are not usually structural pests, they can invade buildings, especially if they find food available. Cotton rats can easily infest garages, barns, storage sheds and similar structures. Lake homes and hunting cabins that are seldom used are also possible places for these rats to invade.

Reproduction

These rats are very prolific. The female rat can produce as many as nine litters per year, with six young per litter. The young are mature in about a month. When there is plenty of food, these rats can reproduce at an amazing rate. When food is scarce, their reproductive rate is lower.

Signs of a Cotton Rat Infestation

Signs of cotton rat activity can include sightings of the rodent or  shallow burrows with multiple entrances.

More Information

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

The first step in controlling any rodent pest is preventing infestation. 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 droppings, contaminated articles or dead rodents.

If rats have invaded, it is advisable to call a pest control professional who possesses the tools and knowledge to address the problem.