In Focus: Nutria Are Somewhat Cute, But an Invasive Pest Nonetheless


If a beaver and a rat had a baby, it might look something like a nutria.

The semiaquatic rodent, which is an invasive species in the Northwest, sports large, orange teeth and a rat-like tail. Yet, its webbed feet and hands, affinity for water and face-shape resemble the native beaver. 

Adult nutria average 24 inches long, with the tail usually accounting for half that. On average, males weigh between 12 and 20 pounds, while females are slightly smaller. 

According to the Washington Department of Fish and Wildlife (WDFW), nutria are native to southern parts of South America, but in the 1930s, they were sold throughout North America to fur farmers and as a means of controlling unwanted aquatic vegetation.

Now, the rodents, albeit somewhat cute as babies, are a pest throughout Western Washington’s wetlands. In Centralia, they frequent Fort Borst Park by the lake, and can often be found around dusk as they come up to the shorelines to eat grass and weeds. Nutria are herbivores.

“Nutria damage is related to burrowing and feeding. Nutria construct burrows in the banks of rivers, sloughs and ponds, sometimes causing considerable erosion,” stated WDFW on its website. “Burrows can weaken roadbeds, stream banks, dams and dikes, which may collapse when the soil is saturated by rain or high water. Rain action can wash out and enlarge collapsed burrows and compounds the damage.”

While the department prohibits ownership of nutria and encourages residents to report sightings, noxious weeds and other more immediately-threatening invasive species taking priority for conservation districts, counties and the state.

As is the case with noxious weeds, the bulk of land protection against nutria, then, falls on landowners. WDFW encourages fences and other barriers, water level management, harassing new nutria that try to establish burrows, and using live traps with sweet potatoes or carrots. 

Read more about managing the pests on property at under the “Preventing Conflict” tab.