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Damage Prevention and Control Methods:Rat

  • Exclusion 
  • Cultural Methods 
  • Remove dense vegetation 
  • Repellents 
  • Toxicants 
  •  Bait 
  •  Fumigants 
  •  Traps 
  •  Snap traps (rat traps) live traps

It is important that only a licensed applicator implement or supervise the use of toxicants, baits or fumigants.

The cotton rat is a moderately large, robust rodent with a scaly, sparsely-haired tail that is shorter then the combined head and body. Cotton rats have relatively large eyes. The ears are large but almost hidden in the fur. They have four toes plus a small thumb on their front feet and five toes on each hind foot. The cotton rat has very small internal cheek pouches. Distinguishing characteristics are the rough grizzled appearance of the blackish or grayish fur with rather stiff black guard hairs. The total length averages 10 inches (25 cm) including the tail length of 4 inches (10 cm).

The cotton rat may be distinguished from the Norway rat by its smaller size, shorter tail, and longer grizzled fur. Evidence of cotton rat presence is a stem and grass cutting of 2 or 3 inches (5 or 8 cm) in length piled at various locations along the runways, which are 3 to 5 inches (6 to 13 cm) wide. Pale greenish or yellow droppings, about 3/8 inch (9 mm) in length and 3/16 inch (5 mm) in diameter, may also be present along the runways
The cotton rat occurs from the southeastern tip of California, southern Arizona and New Mexico; north to eastern Colorado; Eastward through the southern portion of Kansas and Missouri; through Tennessee and North Carolina and southward along the Atlantic coast through Florida, the Gulf States, and up the Rio Grande Valley

Cotton rats prefer dense cover such as a grassy field, overgrown roadsides, or fence row vegetation adjacent to cultivated fields. They will also occupy meadows, marshy areas, cactus patches and weedy ditch banks. Under this protective cover, the cotton rat will have well-defined runways radiating in all directions from the nesting site.

Cotton rats are normally vegetarian, eating the root, stems, leaves, and seeds from a wide range of plants. They will also feed on sugar cane, fruits, berries, and nuts. Cotton rats will cut tall plants off at the base and continue to cut them into shorter sections. Cotton rats also have carnivorous tendencies and will eat insects, eggs of ground-nesting birds, particularly quail, as well as young birds. They will also eat the carcasses of dead animals

Cotton rats are basically nocturnal but will venture out in the daytime and are active year-round the home range is small - from 1/4 to 3/4 acre (.1 to .3 ha) for females and 1 to 1 1/4 acres (.4 to 5 ha) for males. Cotton rats do not store food or hibernate they can swim and do not hesitate to do so. This species is excitable, pugnacious and aggressive towards mice living in the same fields. Their nest is a crude mass of dry grass fibers stripped from larger plant sterns, placed in shallow surface depressions, among clumps of coarse grasses, underground in shallow tunnels, or under rocks or logs.

The species is very prolific and will breed throughout the year. Several litters may be produced annually, averaging 2 to 15 per litter. The gestation period is 27 days; the young are weaned in 10 to 15 days most young breed for the first time at 2 to 3 months of age. Therefore, several generations may live in the same nest at one time. The average life span is 6 months

Cotton rat populations have great fluctuations and cause the most-serious damage during population peaks. They may damage a variety of crops including alfalfa, grains, grasses, vegetables, peanuts, fruit crops, sweet potatoes, and sugar beets. Cotton rats are especially troublesome in sugarcane and melons. Since these animals will eat quail eggs, a high cotton rat population may have a detrimental impact on quail nesting success. Cotton rats also compete with quail for the same foods.

Last updated: 5/16/2011 11:06:36 AM