Apr 18, 2026 01:58 AM
https://www.smithsonianmag.com/smart-new...180988554/
INTRO: For the past nine years, wildlife officials have been battling nutria, a large, semiaquatic rodent with a long tail and beaverlike teeth that’s native to South America. The destructive critters, which can wreak havoc on wetlands, crops and water infrastructure, were discovered in 2017 in San Joaquin Valley, an agricultural area in the middle of the state. That was a bit of an unwelcome surprise, because nutria were thought to have been wiped out in California in the 1970s.
Now, authorities have come up with a possible explanation for how the animals ended up there again. Recent genetic testing conducted by the California Department of Fish and Wildlife (CDFW) has revealed that the state’s nutria are closely related to a population in central Oregon.
The findings suggest that the pests got a little help crossing state lines from humans, who deliberately—and illegally—transported them to California, CDFW announced on April 7. Scientists detailed their research in a study published last November in the journal Evolutionary Applications.
“Given where nutria were rediscovered in California, it is nearly impossible that they could have migrated there on their own,” Michael Buchalski, a geneticist for CDFW, writes in an email to SFGate’s Ariana Bindman. “It’s too far of a distance, and we don’t find any nutria in the areas in between. That makes human introduction the most likely scenario.” (MORE - details)
INTRO: For the past nine years, wildlife officials have been battling nutria, a large, semiaquatic rodent with a long tail and beaverlike teeth that’s native to South America. The destructive critters, which can wreak havoc on wetlands, crops and water infrastructure, were discovered in 2017 in San Joaquin Valley, an agricultural area in the middle of the state. That was a bit of an unwelcome surprise, because nutria were thought to have been wiped out in California in the 1970s.
Now, authorities have come up with a possible explanation for how the animals ended up there again. Recent genetic testing conducted by the California Department of Fish and Wildlife (CDFW) has revealed that the state’s nutria are closely related to a population in central Oregon.
The findings suggest that the pests got a little help crossing state lines from humans, who deliberately—and illegally—transported them to California, CDFW announced on April 7. Scientists detailed their research in a study published last November in the journal Evolutionary Applications.
“Given where nutria were rediscovered in California, it is nearly impossible that they could have migrated there on their own,” Michael Buchalski, a geneticist for CDFW, writes in an email to SFGate’s Ariana Bindman. “It’s too far of a distance, and we don’t find any nutria in the areas in between. That makes human introduction the most likely scenario.” (MORE - details)
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