The nutria is a large rodent that looks like a large rat or a beaver. Wikipedia Oh rats.

A very large rodent that looks like a beaver with a rat-like tail is destroying coastal Louisiana, chomping its way through the state's wetland vegetation and removing the plants and grasses that are critical to preventing these marshes from turning into open water.

The nutria, a web-footed animal with shaggy, brown outer fur and large, orange teeth, is originally from South America. The swamp creature was brought to the United States in the early 19th century and farmed for its fur. But as fur declined in popularity over the next century, many farms were shut down. Some animals were released into the wild by their owners, others are believed to have escaped.

By the 1950s, there were around 20 million nutria running around coastal Louisiana, according to the U.S. Geological Survey. Today that number has been vastly reduced thanks to a series of efforts to control overpopulation, including a $4 bounty on each nutria tail and an extensive trapping and harvest program. There is also a growing market for nutria meat, which is high in protein.

The large rodents have voracious appetites, which in turn, is destroying Louisiana's wetland vegetation. Wikipedia Documentary filmmaker Chris Metzier, who is currently making a movie about nutria called "Rodents of Unusual Size" (taken from the name of creatures that lived in the fire swamp in "The Princess Bride"), said in an interview with Take Part that the Louisiana nutria population is presently around 5 million.

Nutria are known for their hearty appetite and remain a serious threat to Louisiana's wetlands because they feed on the roots of plants. Without the root system to hold the soil together, the land becomes even more vulnerable to erosion and flooding.

The Louisiana government estimates that at any one point in time, nutria impact more than 46,000 acres of Louisiana's coastal wetlands. The silver lining is that that number is down from 80,000 acres, before nutria-control methods were implemented in 2002.