The cotton mouse is the largest and heaviest of the three species of Peromyscus found in the park. The cotton mouse is a species of the southeastern states. It is found from southeastern Virginia to southern Florida and west to southeastern Oklahoma and eastern Texas. Cotton mice are most commonly found in timbered swampland along the floodplains of streams and rivers and in brushy areas near water. Cotton mice are nocturnal and are active all year.

Species Measurements:
- Adult Total Length: 175-200 mm (7-8 in.)
- Tail: 70-90 mm (2?-3? in.)
- Hind Foot: 21-26 mm (⅞-1⅛ in.)
- Weight: 28-56 g (1-2 oz.)

Physical Characteristics:
The cotton mouse is the largest and heaviest of the three species of Peromyscus found in the park. In appearance, it is very similar to the white-footed mouse (Peromyscus leucopus). Color ranges from dark sooty to tawny brown above and whitish below. The middorsal area is darker than the sides. The feet are white. The indistinctly bicolored tail is sparsely haired and is less than half the total length. Like all Peromyscus, cotton mice have large eyes and ears.
Adult cotton mice can frequently be distinguished from white-footed mice by hind foot size. The white-footed mouse seldom has a hind foot larger than 23 mm (range 19-24 mm), whereas the hind foot of the cotton mouse is seldom shorter than 23 mm (range 23-26 mm). Thus, the cotton mouse differs from the white-footed mouse in its slightly larger size, its larger hind foot, and its slightly darker color.

Habitat:
Cotton mice are most commonly found in timbered swampland along the floodplains of streams and rivers and in brushy areas near water. They are found around logs, stumps, hollow trees, stone walls, and piles of rocks.

Reproduction:
Breeding usually extends from early spring into fall. The Komareks recorded two females, each containing three embryos, on March 14. Linzey recorded a nursing female (plac. scars 1R, 2L) on August 26, and males in breeding condition in August, September, and October. Gestation requires approximately 23 days. Litters average 3 to 4 young (range 1-7). Young cotton mice are naked, blind, and helpless. The incisors erupt about the seventh day, the young are fully haired by day 10, and the eyes open between days 12 and 14. Weaning occurs between the third and fourth weeks.

Longevity:
The average wild cotton mouse survives for four to five months. Few live longer than one year.

Terrestrial Ecology:
Cotton mice are nocturnal and are active all year. Their senses of smell, sight, and hearing are well developed. Drumming similar to that described for the white-footed mouse (Peromyscus leucopus) has been observed in this species. Food consists primarily of seeds, fruits, nuts, and invertebrates.

Predators and Defense:
All instances of predation involving Peromyscus sp. are reported in this account of Peromyscus gossypinus, since remains of mice of this genus found in the stomachs of predators have not been identified to species. Three timber rattlesnakes (Crotalus horridus) taken near Laurel Creek, Trillium Gap, and Gregory Bald had eaten Peromyscus sp. (Stupka, 1945, 1947, 1954 ). Peromyscus were recorded in the stomachs of 21 of 44 timber rattlesnakes examined by Savage (1967). The stomachs of two screech owls (Otus asio) found at the Townsend Y and near park headquarters also contained remains of these mice (Stupka, 1938, 1949). A long-tailed weasel (Mustela frenata) seen on Mt. LeConte near LeConte Lodge was carrying a Peromyscus. A specimen was removed from the stomach of a bobcat (Lynx rufus) killed along the Newfound Gap Road in Tennessee (Stupka, 1952).

Parasites:
Komarek and Komarek (1938) found roundworms in the stomachs of several individuals. Linzey (1995b) removed a flea, Peromyscopsylla hesperomys, from one specimen.

The cotton mouse is a species of the southeastern states. It is found from southeastern Virginia to southern Florida and west to southeastern Oklahoma and eastern Texas. Although found principally on the Coastal Plain, this species does extend into the Piedmont region and into the foothills of the mountains.

The Komareks stated that cotton mice were frequently found "in the open woodlands and field margins at low elevations where farming activity has produced brush growth and open forest situations." Linzey (1995b) has frequently taken this species in a floodplain along Cosby Creek. Cotton mice have been recorded in the park at elevations ranging from 1,442 to 2,800 feet.

References:

Komarek, E. V. and R. Komarek. 1938. Mammals of the Great Smoky Mountains. Bulletin of the Chicago Academy of Sciences 5(6): 137-162.

Linzey, A.V. 1999. Cotton Mouse. Pages 569-570. In: D.E. Wilson, and S. Ruff (eds.). The Smithsonian Book of North American Mammals. Smithsonian Institution Press, Washington, D.C.

Linzey, D. W. 1968. An Ecological Study of the Golden Mouse, Ochrotomys nuttalli, in the Great Smoky Mountains National Park. American Midland Naturalist 79(2): 320-345.

Linzey, D. W. 1995a. Mammals of Great Smoky Mountains National Park. The McDonald & Woodward Publishing Company, Inc., Blacksburg, Virginia.

Linzey, D. W. 1995b. Mammals of Great Smoky Mountains National Park-1995 Update. Journal of the Elisha Mitchell Scientific Society 111(1): 1-81.

Linzey, D. W. 1998. The Mammals of Virginia. The McDonald & Woodward Publishing Company, Inc., Blacksburg, Virginia.

Savage, T. 1967. The Diet of Rattlesnakes and Copperheads in the Great Smoky Mountains National Park. Copeia 1967 (1): 226-227.

Stupka, A. 1935-63. Nature Journal, Great Smoky Mountains National Park. 28 volumes (years) each with index. (Typewritten copy in files of Great Smoky Mountains National Park library).

Wolfe, J.L. and A.V. Linzey. 1977. Peromyscus gossypinus. Mammalian Species No. 70: 1-5. American Society of Mammalogists.