High Quality Content by WIKIPEDIA articles! The marsh rice rat (Oryzomys palustris) is a semiaquatic North American rodent in the family Cricetidae. It is found mostly in the eastern and southern United States, from New Jersey and Kansas south to Florida and northeasternmost Tamaulipas, Mexico; its range previously extended further west and north, where it may have been a commensal in corn-cultivating communities. It usually occurs in wet habitats such as swamps and saltmarshes. Weighing about 40 to 80 g (1.4 to 2.8 oz), the marsh rice rat is a medium-sized rodent that resembles the common black and brown rat. The upperparts are generally gray-brown, but reddish in many Florida populations. The feet show several specializations for life in the water. The skull is large and flattened and is short at the front.