Holochilus

The swamp rats ( Holochilus ) are a genus of Neuweltmäusen who live as shore residents in swamp areas of South America. They were usually placed near the cotton rat ( Sigmodon ), but new molecular genetic analyzes suggest that they ( Oryzomys ) are related with the dense rice rats.

The body length is depending on the type 13 to 22 inches, added an approximately equally long tail. The coat color is beige or brown on the upper side and lower side white. The body is typical of rats shape. Of the externally very similar to cotton rats, the swamp rats differ primarily in the webbing between the toes, as well as by the softer fur.

Are widespread swamp rats in tropical and subtropical South America east of the Andes. Here they live on river banks, in swamps and reed forests. From reeds and leaves a nest is built, which depends up to 3 feet above the water in reeds or bushes. A swamp rat's nest has a diameter of up to 40 centimeters. Residents jump event of danger directly into the underlying water and escape by swimming.

In some regions, swamp rats are extremely common. Among the areas that provide them with perfect conditions, is one of the Pantanal in south-western Brazil. Here one counts in some bushes up to ten nests. In a few years it also comes to sudden population explosions, whose causes are not fully understood. This rapid growth of populations are associated with the incidence of swamp rats in adjacent settlements. But you end up just as suddenly by an equally mysterious mass death of animals.

The following types are known:

• The bald rat ( Holochilus brasiliensis ) lives in Brazil, Paraguay, Uruguay and northern Argentina.
• Holochilus sciureus inhabited Brazil, Bolivia, eastern Peru, Venezuela, Guyana, Suriname and French Guiana.
• The Chaco Swamp Rat ( Holochilus chacarius ) is native to Paraguay and northern Argentina.

A fourth type, Holochilus magnus, is now found mostly in its own genus Lundomys.