Invasive Species Alert: Nutria Control Window Closing In California: State Authorities Ask For Help In Eradicating Destructive Rodent

Nutria does sound like a palatable health drink, but the reality is very different. Nutria are large rodents (rats) that are currently found in 20 of the United States. Efforts are afoot to control them. However, the nutria control window in California appears to be closing.

A large male California nutria captured in 2017. Big and destructive they are definitely on the radar as authorities try to keep the nutria control window open. CDFW photo.

According to the California Department of Fish and Wildlife (CDFW) 3,300 of the animals have been captured in 9 of California’s 58 counties. The better news is that the total is over a five year period and the majority were caught in one county. So the CDFW believes the nutria control window is still open.

The nutria (Myocastor coypus) is a very large rodent native to South America. It has made its way across much of the world, partly because it was introduced for its fur. That market collpased and many were released in many regions. That is a familiar tale in invasive species lore. Animals introduced into non-native areas and then abandoned. Nutria, pythons, swamp eels, cats and many other creatures are on the list. The United States Army introduced camels into Texas in the 1850’s. The project was abandoned after the U. S. Civil War. Apparently a few escaped and others were imported by non-military people. Any wild camels have since died out.

CDFW says the nutria is very destructive:

“Through their extensive herbivory and burrowing habits, nutria have devastating impacts on wetland habitats, agriculture, and water conveyance/flood protection infrastructure. Nutria consume up to 25% of their body weight in above- and below-ground plant material each day. Due to their feeding habits, up to 10 times the amount of plant material consumed is destroyed, causing extensive damage to the native plant community, soil structure, and nearby agricultural crops. The loss of plant cover and soil organic matter results in severe erosion of soils, in some cases converting marsh to open water. Further, nutria burrow into banks and levees, creating complex dens that span as far as 6 meters deep and 50 meters into the bank and often cause severe streambank erosion, increased sedimentation, levee failures, and roadbed collapses.”

Brittanica says they are superb web-footed swimmers. The largest weigh almost forty pounds. They produce litters of up to eight young. As many as three litters a year. They are mature at six months. Their distinctive orange teeth are due to a high concentration of iron in the enamel.

A CDFW graphic. CDFW thinks California is around position 1. Position 2 is where Maryland started. Acting now could eradicate the nutria faster and more cheaply. By point three the nutria control window is shut.

So far, Maryland is the only state that has eradicated a nutria population. California feels there is still a small nutria control window of opportunity. Maryland, it should be noted, took 20 years to control the problem. Hunting, tracking and tracker dogs were all employed in the expensive fight.

black and white eagle
Bald eagles (Haliaeetus leucocepahlus) eat nutria. So do alligators, some snakes and other predators. But apparently not enoogh.Photo by Pixabay on

Published by ursusrising

long time writer and editor living in Los Angeles

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