Nutria, also called Myocaster coypus (latin for mouse beaver), are large rodents native to South America that wreaked havoc on the Chesapeake Bay's wetlands when they were imported in the 1940's for the fur trade.But now nutria face their last stand on Maryland's Eastern Shore. There are almost none left alive after an intensive, more than decade-long trapping campaign by federal and state government agencies.Wildlife managers conducted a successful eradication campaign against the invasive species because they eat the roots of wetlands plants. This accelerates the erosion of marshes that are important breeding grounds for fish and birds, and also work as water pollution filters that clean the Chesapeake Bay.