Nutria

From USFWS National Wildlife Refuge System:

Some invasive species are pretty or at least interesting – especially certain ornamental plants. And then there are nutria, this beaver-like mammal native to South America and brought to the United States to establish a fur trade in the 19th century. Apparently not enough people found a nutria coat very fashionable. In Louisiana for a time, there were even efforts to sell the meat. Since their release into the wild, nutria can be found all across the U.S. As an invasive species, nutria compete for food sources with native animals and often damage natural ecosystems. Now you know. This is National Invasive Species Awareness Week.http://www.fws.gov/invasives/nwrs.html
nutria