Marsh Rice Rats In-Depth


The marsh rice rat is a rodent that is in the cricetidae family. It is found mainly in North America. It is found in the wetland habitats like salt marshes and swamps. The rat weighs around 40-89 grams translating to 1.4-2.8 oz. This rat is medium in size and resembles the common brown or black rat. Its upper parts are usually gray or brown, but the Florida populations are usually reddish in color. The feet of the rice mouse have got some specializations, allowing it to do well in water. It has a large skull that is rather flattened. The front of the head is short.

The marsh rice ray was discovered back in 1816 by john Bachman. Marsh rice rats are nocturnal and they can build runways.

Marsh rice rats have got a tail that is scaly. His tail is usually longer than the body and the head. The rat is grayish brown in color, and it lives within tidal marshes in different parts of the world.

AppearanceMarsh Rice Rats 1

The body of marsh rice rat is usually slender and is covered in very coarse and grayish brown kind of fur. It also has blackish hairs. The tail is around 7 inches in length. The belly, the feet and the tail underside is whitish or light grayish. The rats are around 5 inches in length and they weigh around 3 ounces.

The marsh rice rat has different color codes on its coat with the upper parts being grayish brown and a head that is a bit lighter. The under parts and the feet are white. The rat also has some small cheek pouches. The ears look like the upper parts in color, but there is light hair right at the front. Its tail has got a dark brown color but appears much paler below.

As this rat swims, its fur traps air and this causes it to be more buoyant. This also reduces the event of heat loss. The female marsh rice rats have got some eight mammae.

The front feet have got four digits while the hind ones have got five. The fore feet do not have the ungula tufts. The hind feet are rather broad and the fifth digit is somewhat shorter. There most of the pads are much reduced and so are the tufts. However, these feet have got interdigital webs that are rather small.


Marsh rice rats are mostly nocturnal. They live within swamps and tidal marshes. They prefer areas that have a lot of sedges and grasses. They are semi aquatic, meaning that they do spend time in water and on land.

RangeMarsh Rice Rats 2

These mice are abundant in Delmarva Peninsula as well as the coastal plains of Virginia and Maryland.


Marsh rice rats are opportunistic feeders. The rat will eat anything that is available in its surrounding. This includes aquatic plants, sedges and grasses. Also, they feed on fiddler crabs, bird eggs, fishes, snails, and even insects.


There are some animals that feed on the marsh rats and they include owls. There are other predators such as snakes, foxes, raccoons, weasels, minks and hawks.

Life cycle and reproduction

Breeding in these rats occurs a couple of times from March to October. The females usually reproduce a couple of litters that have 3 to 5 young ones every year. The rats build nests that are the size of a softball and woven with sedhers and grasses. The nests are well hidden way above the mark of the high tide.

The gestation of the rats lasts around 25 days. The young are totally helpless and blind at birth. Their eyes open in the second week after birth. At this time, the young ones can eat solids. Sexual maturity in the females is achieved by the sixth week of life. Usually, the life span of the marsh rice rats does not exceed one year.

Dental formula

Marsh rice rats have a dental formula of×2.  This adds up to 16. There is one lower and one upper incisor and three lower and three upper molars. This is the norm in the muroid rodents. The incisors are very well developed, especially the upper ones and they are strongly opisthodont. The chewing edge is just behind the teeth’s vertical plane. Molars are bunodont. Cusps are much higher than connecting crests. They are also low crowned.

More factsMarsh Rice Rats

  • The marsh rice rats are highly skilled as swimmers and they can dive for over 30 feet in the water.
  • They have undercoats that are water repellant
  • The rats occasionally take over the nests of other animals such as the blackbirds and make them their own
  • Marsh rat uses the feet so as to propel its body while in the water.
  • If the rat comes face to face with danger, it usually hides under water. The common natural enemies of the rat include snakes, foxes, raccoons, minks, hawks and owls
  • It is a solitary kind of animal. It is also very territorial
  • This rat cleans fur and defecates away from its burrows. It does this in very specific areas
  • The marsh rice rat doesn’t hibernate when winter comes. It remains active through the year.
  • Its mating season is between march to October
  • Females can have around 8 quarters in a single year. The females can actually conceive right after birth.

The Common names

There are many names that have been proposed for this rat. The people who described it earlier used the term rice meadow –mouse or rice field mouse. Rice rat, swamp rice rat and marsh mouse came in the early 1900. There are different subspecies that received common names like the swimming rice art and Florida marsh mouse and central Florida rice rat. Other terms that have been used to refer to this rat include Texas rat mouse, everglades rice rat, and Cape Sable rice rat and bangs marsh mouse.

Marsh rice rats are considered to be a threatened species within Illinois. It is an endangered species within Florida Keys. However, the populations of the rats in other areas are stable and quite large.

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