Cotton Mouse
Order Rodentia : Family Muridae : Peromyscus gossypinus (Le Conte)

Description. A medium-sized, heavy bodied, white-footed mouse; tail much shorter than head and body, between three and four times the length of hind foot and not sharply bicolor, but darker above than below; ears small (16-18 mm from notch); upperparts mummy brown, the mid-dorsal area suffused with black; sides bright russet; underparts creamy white; feet white, but tarsal joint of heel dark like leg. External measurements average: total length, 180 mm; tail, 78 mm; hind foot, 23 mm. Weight, 34-51 g.

This mouse is most easily confused with the white-footed mouse (Peromyscus leucopus), from which it can be distinguished by larger size (weight usually over 30 g in adults as opposed to 15-25 g in leucopus) and longer skull (27 mm or more in gossypinus and less than that in leucopus).

Distribution in Texas. Found in woodlands in eastern one-fourth of state.

Habits. Cotton mice are typically woodland dwellers and occur along water courses where stumps, down logs, and tangles of brush and vines offer suitable retreats; frequently they occur in woodland areas bordering open fields. They have been trapped in eastern Texas in canebrakes, under logs, and around and in old, tumbledown buildings in wooded areas. That they are adept at climbing and may live off the ground in hollows in trees as indicated by the capture of individuals in live traps set on platforms in trees.

Their other habits are not well-known. Nothing specific is known of their natural foods, although cotton mice are omnivorous. Over one-half of their diet may be made up of animal matter and food availability probably determines the dietary composition. Captive mice seemed to relish rolled oats, wheat, corn, and bread. Green foods were eaten sparingly.

Breeding may occur throughout the year although there is a decline in reproductive activity during the summer months. In Texas, most breeding commences in late August, reaches a peak in November, December, and January and subsides by early May. The gestation period is about 23 days in non-nursing females and about 30 days in females which are nursing a previous litter. Adult females may produce four or more litters a year. The litter size ranges from one to seven and averages three or four. The young are naked and blind at birth. Their ears open in 5 or 6 days at which age their incisor teeth erupt. Their eyes open in about 13 days and shortly after that they begin to eat solid foods. They are completely weaned at an age of 20-25 days. They become sexually mature at about 60-70 days of age.

The name cotton mouse was applied to the species by Le Conte, who found that the mice often used cotton for nest construction. Ordinarily, however, they do little or no damage to cotton or foodstuffs.