South America nutria rats — orange-toothed rodents that can grow as large as 40 pounds or twice the size of a raccoon — are a growing threat to California’s levees that protect upwards of 7 million people living in floodplains

The invasive species burrow into earthen levees undermining their integrity.

Yet as California faces months of touch-and-go levee watches required to monitor an enormous spring Sierra snowmelt, the U.S. Fish and Wildfire Services is seeking to cut federal money funding of efforts to control the non-native rodent population by 60 percent

On Wednesday Representative Josh Harder appeared before the House Appropriations Subcommittee on Interior, Environment, and Related Agencies with ‘Nellie’, a taxidermized nutria, demanding answers as to why funding is being slashed.

“When I came to Congress, I didn’t think I would be leading the charge to eradicate swamp rats, but this is a real issue, and we have to act quickly before they fully invade our waterways” Harder said. “I understand they’re not in everyone’s backyard, but they’re in mine. And a lot of folks in my area would rather not have to wake up to these “nacho cheese” teeth every morning.”

The nutria also are considered a major threat to local ecological systems. As such, they are a major threat to the Delta with its 1,115 miles of levees and waterways where a number of fish and other species are struggling to survive.

The nutria — that have been found in Stanislaus and San Joaquin counties —  can consume up to 25 percent of their body weight with above and below ground vegetation each day. 

One female nutria can reproduce 200 offspring in a year.

There are 7 million Californians living in floodplains of which most is protected by 13,500 miles of levees that are prime habitat for the nutria.

Many of those levees are now under increased stress from the series of storms slamming California this year.

The nutria are another wildcard that threatens the integrity of flashpoint levees such as between the Stanislaus River and the Old River Channel along the San Joaquin  River.

This stretch of levee south of Manteca that passes through Lathrop is vulnerable to flooding due to a narrow channel that wrestles with water flows draining the 15,600 square mile San Joaquin  River watershed just before it enters the Delta.

The Nutria carries pathogens and parasites as well.

The California Department of Fish and Wildlife said the Nutria strongly resembles the beaver, but with highly-arched backs and long, thin, sparsely haired tails rather than wide and flattened tails like that of a beaver.  The adult Nutria is over five times the size of a muskrat and about one-third the size of an adult beaver.  

Nutria have caused millions of dollars in damage to wetlands in several states including Maryland and Louisiana.

Nutrias reach their sexual maturity as early as three months old. 

They have been found in 30 states and established currently in 17 including Oregon, Washington and California.

The rodent was introduced in the United States at Elizabeth Lake in 1899 for its mink-like fur but it reportedly failed to reproduce. 
Nutria ranches were later introduced to meet the needs of the fur market in the 1940s until the market collapsed with many of the Nutria animals being released into the wild. 
 Harder originally appeared with the stuffed rodent in 2019 when he introduced a bill to direct $7 million in funding towards nutria management in California. 

Nutria are known to damage farmland, increase the risk of flooding, and endanger local ecosystems.

 If unmanaged, the nutria population could grow to 250,000 in California within 5 years.

Harder addressed Tracy Stone-Manning, Director, Bureau of Land Management, Martha Williams, Director, U.S. Fish and Wildlife Service, and Charles F. Sams III, Director, National Park Service during the hearing.

State officials are asking that if the Nutria is found in the Central Valley that it not be released.  Immediately contact the California Department of Fish and Wildlife Invasive Species Program to report the sighting at www.wildlife.ca.gov/Conservation/invasies/report.

To contact Dennis Wyatt, email dwyatt@mantecabulletin.com