The underparts are soiled white, white, or creamy. The conspicuous ears are practically naked. Many individuals are mottled with gray, or almost spotted, mainly on the anterior half of the upper parts. This mottling may be inconspicuous, may form irregular small spots or large blotches, or may cover almost all of the upper parts. In some forms there is a fairly definite, almost white stripe across the back just behind the shoulders.
Females have eight mammae.
These rats dwell in forests and thickets. They are nocturnal but have been seen foraging during the day, at which time they behave as if they were almost blind, sitting on their haunches and sniffing in all directions. They can climb well, using the long tail for balancing, and can swim. Reproduction takes place at various times of the year. Litters numbered 1-5, most commonly 4, young.