Nutria are relatively large rodents native to wetlands in South America that were first brought to the US for fur harvesting in the 1800s. They were then released into the wild in the 1930s after the fur trade collapsed. Nutria create burrows connected by tunnels and live in groups that typically consist of up to 13 individuals. Nutria populations can grow rapidly as they can have up to three litters a year with up to 13 offspring per litter. Nutria are considered one of the worst invasive species on the planet, given their quick reproductive abilities, veracious appetite for wetland plants, and ability to modify wetland landscapes.
Nutria are native to South American countries including Brazil, Bolivia, and Argentina. Upon their introduction to the US in the early 1900s, they have spread across the Gulf Coast and into the northwestern states like California and Washington. Although there are no confirmed reports or established populations in Canada, British Columbia is considered high risk due to its proximity to established US populations.
Impacts of Nutria
- Consume primarily aquatic and semi-aquatic wetland vegetation, reducing habitat and diminishing native plant populations.
- Reduce bank stability by creating extensive burrows, removing integral vegetation, and can alter wetland habitats.
- Can damage infrastructure, such as bridges, culverts, and roadways by altering shorelines and reducing bank integrity.
- Nutria burrows threaten flood-control systems that protect low-lying regions.
- Can alter water supply to agricultural fields and can lead to declines in crop yields.
- Can spread parasites and diseases, such as tuberculosis, tapeworms, and liver flukes.
How to Identify
- Nutria are a large rodent like a beaver or muskrat. They are smaller than a beaver, but larger than a muskrat.
- Nutria have rounded tails like rats, unlike the tails of beavers, which are horizontally flattened, or muskrats which are vertically flattened. Nutria also do not undulate their tails when swimming.
- Their eyes, ears, and nostrils are located higher up on their body to allow them to remain above the waterline while swimming.
What You Can Do
- Learn how to identify nutria and prevent the spread of this unwanted species.
- If you have seen a nutria or another invasive species in the wild, please contact the toll-free Invading Species Hotline at 1-800-563-7711, visit EDDMapS.org, or search for the ‘Invasive Species in Ontario’ project on iNaturalist.org to report a sighting.
OFAH/OMNRF Invading Species Awareness Program. (2023). Nutria. Retrieved from: www.invadingspecies.com.
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Header photo by twan3253 | iNaturalist