The muskrat is a medium-sized rodent native throughout North America. They are sometimes confused with beavers, though they are much smaller. They are semi-aquatic, spending time both on land and in rivers, lakes, and wetlands. Muskrats are mostly vegetarian, feeding on aquatic plants such as cattails, but they are also known to eat mollusks, shellfish, fish, frogs, and sometimes small turtles. Muskrats build dens for their families in the sides of lakes or riverbanks, burrowing up into the den from underwater for protection. Muskrat Cove, a park along the Bronx River which crosses the border between the Bronx and Westchester County, is named for the large population of muskrats that inhabit it.