The pelage is brown on top with some white underneath, especially on the underside of the tail, which gives this genus the common name of cottontail. Ears are of medium size, around 2.6 inches in length.
Hair is short and thin.
The diet of S. aquaticus consists of marsh and swamp plants and reeds as well as cultivated plants. The soft green pellets are reingested to maximize the nutrients gained from food. Reproduction During the breeding season, males fight to gain access to females in estrous. Breeding in this species occurs almost year round. After a gestation period of 40 days, between 1 and 6 young are born.