Oryzomys palustris
TAXONOMY
Oryzomys palustris (Harlan, 1837), near Salem, New Jersey, United States. Tribe Oryzomyini.
OTHER COMMON NAMES
Spanish: Rata arrocera, coludo.
PHYSICAL CHARACTERISTICS
Total length 8.9–12.0 in (225–305 mm), tail length 3.9–6.9 in (100–175 mm), hindfoot length 1.1–1.5 in (28–37 mm). Weight 1.4–3.0 oz (40–85 g). Generalized rat-like appearance. Dorsal coloration range varies from grayish brown to gray. The venter is much lighter. The underfur is water repellent. Eight pairs of mammary glands. The forefoot and hindfoot have four and five toes, respectively. Tail is scaly, long, and nearly naked.
DISTRIBUTION
Endemic to the United States, ranging from southeastern Pennsylvania and southern New Jersey to the tip of Florida and westwards to eastern Texas. There are records from southern Kentucky and Illinois, southwestern Missouri, and southeastern Oklahoma.
HABITAT
Common in wetlands, including marshes at the Atlantic and Gulf coasts. It also inhabits swamps, meadows, and prairies.
BEHAVIOR
Semiaquatic, being good swimmers and divesr. Primarily nocturnal. High-pitched squeaks were associated with agonistic behavior upon females by males in captivity. It constructs spherical grassy nests to sleep in during the day.
FEEDING ECOLOGY AND DIET
Carnivorous, but also feeds on seeds, succulent plant parts, and fungus. Food items may vary seasonally upon resource availability.
Animal items vary, but insects, fiddler crabs, snails are the most common; other animal items are fishes, clams, eggs, and young of long-billed marsh wrens.
REPRODUCTIVE BIOLOGY
Breeding may occur throughout the year, although it may be low during hot summer months. Gestation period lasts between 21 and 28 days. Different average litter size has been reported, 3.6, 4.8, and 5. Newborn weigh around 0.1 oz (3.5 g). Weaning occurs at age 11–20 days. Sexual maturity is reached between 40 and 45 days of age. Life expectancy is generally less than one year.
CONSERVATION STATUS
Not threatened.
SIGNIFICANCE TO HUMANS
Reservoir of the Bayou hantavirus, a pathogenic virus associated with human pulmonary syndrome.
