I saw this nutria this afternoon in a small canal not far from home. Nutria are considered to be an invasive species, and as a result have taken over the area with no natural enemies here.

Information about the nutria from Wikipedia:

"The coypu (from Spanish coipú, from Mapudungun kóypu, Myocastor coypus), also known as the river rat or nutria, is a large, omnivorous, semiaquatic rodent and the only member of the family Myocastoridae. Originally native to subtropical and temperate South America, it has since been introduced to North America, Europe, Asia, and Africa, primarily by fur ranchers. Although it is still valued for its fur in some regions, its destructive feeding and burrowing behaviors make this invasive species a pest throughout most of its range. Coypus live in burrows alongside stretches of water. They feed on river plant stems."