Text Size: A  A  A

Marsh Rice Rat

Oryzomys palustris

Marsh rice rats have a scaly tail that is usually longer than their head and body. (Roger Barbour)
Marsh rice rats have a scaly tail that is usually longer than their head and body. (Roger Barbour)

The marsh rice rat is a grayish-brown rodent with a long tail. It lives in tidal marshes near the Chesapeake Bay in Delaware, Maryland and Virginia.


  • Long, slender body
  • Coarse, grayish-brown fur with some blackish hairs
  • Scaly tail that is usually longer than the head and body (about 7 inches long)
  • Belly, feet and underside of tail are light grayish or whitish
  • Grows to about 5 inches long and weighs less than 3 ounces


  • Lives in tidal marshes and swamps
  • Prefers areas with plenty of grasses and sedges
  • Semi-aquatic, meaning it spends time both on the land and in the water
  • Mostly nocturnal


  • Found throughout the Delmarva Peninsula and within the coastal plain in Maryland and Virginia


  • An opportunistic feeder, meaning it eats whatever is available
  • Foods include insects, snails, fishes, bird eggs and fiddler crabs as well as grasses, sedges and aquatic plants


  • Owls are a major predator
  • Other predators may include hawks, minks, weasels, raccoons, foxes and snakes
  • Will often dive underwater when threatened

Reproduction and Life Cycle:

  • Breeds several times between March-October
  • Females can produce several litters of 3-5 young each year
  • Builds a softball-sized nest of woven grasses and sedges in hidden areas above the high-tide mark
  • Gestationperiod lasts about 25 days
  • Young are born blind and helpless
  • By early in their second week of life, young open their eyes and are able to eat solid food
  • Females reach sexual maturity within six weeks of age
  • Usually does not live longer than one year

Other Facts:

  • A skilled swimmer that is able to dive more than 30 feet deep and swim across nearly 1,000-foot stretches of water

Sources and Additional Information:


Click tabs to swap between type and habitat.

410 Severn Avenue / Suite 112
Annapolis, Maryland 21403
Tel: (800) YOUR-BAY / Fax: (410) 267-5777
Directions to the Bay Program Office
Terms of Use | Privacy Policy
©2012 Chesapeake Bay Program | All Rights Reserved