The Nutria rodent – weighing up to 20 pounds – has been spotted in Stanislaus County causing damage to farm lands and wetlands as well as burrowing holes in levees.
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. They breed year-round and producing two to three litters a year. 
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 two known populations near the California border. The rodent was introduced in the U.S. 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. 
The Nutria carries pathogens and parasites and causes various kinds of damage through burrowing along with intense herbivory, it is being reported by the state agency.  Nutria do not construct dens but they burrow, frequently causing the water retention of flood control levees to breech, weakening structural foundations and eroding banks.  They can consume up to 25 percent of their body weight with above and below ground vegetation each day.  They waste and destroy up to ten times their body weight.
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 Glenn Kahl, email gkahl@mantecabulletin.com.