Courtesy of Centers for Disease Control and Wikimedia Commons
Marsh rice rats are medium-sized rodents that have water-repellent fur and are good swimmers. They eat the soft underwater parts of plants as well as insects, snails, bird eggs, and other small animals. Marsh rice rats live in salt marshes and other wet and swampy habitats.
Salt marshes are wet areas right next to the ocean. Salty ocean water that moves with the tides floods and then uncovers the land in a salt marsh twice each day. Sometimes fresh water mixes with the salt water. All of the animals and plants that live in a salt marsh are used to dealing with lots of salt!
Marsh rice rats usually live for less than one year in the wild. Many animals hunt and eat marsh rice rats including owls, hawks, snakes, foxes, and raccoons. For a marsh rice rat, the tall grass that grows in the marsh provides a source of food and a place to hide from predators.
This salt marsh is regularly covered with salt water when the tide rises. By Ryan Hagerty, courtesy of the US Fish and Wildlife Service
This map was made in 1918 to show where the marsh rice rat lived at the time. The range is similar today. By Edward A. Goldman
The above link plus:
Benyus, Janine M. A Field Guide to Wildlife Habitats of the Eastern United States. New York: Simon and Schuster, 1989. Pp. 72-73