Nutria are large, semi-aquatic rodents. This article explores their physical characteristics, health risks to humans, and the environmental and infrastructural damage they can cause.
Identifying Nutria
Nutria (Myocastor coypus) are large rodents, weighing between 15 to 20 pounds with a body length of about two feet and a tail that can add another 12 to 18 inches. Their most distinctive features include large, bright orange-yellow incisor teeth. Unlike beavers or muskrats, nutria have long, round, sparsely haired tails, and their hind feet are partially webbed. They often appear hump-backed when moving on land.
Native to South America, nutria were introduced to North America, Europe, and Asia for fur farming in the late 19th and early 20th centuries. When the fur market collapsed in the 1940s, many nutria escaped or were intentionally released into the wild. These adaptable rodents prefer habitats near permanent water sources like rivers, lakes, and wetlands, though they can also inhabit brackish coastal waters.
Health Risks to Humans
Nutria can carry various pathogens and parasites that pose health risks to humans. They can serve as hosts for bacteria such as Leptospira, which causes leptospirosis, and Salmonella. Transmission often occurs through contact with water or soil contaminated by nutria urine or feces. Symptoms of leptospirosis can range from mild flu-like illness to more severe conditions affecting the kidneys or liver.
Nutria can also harbor parasitic worms. One notable parasite is Strongyloides myopotami, a roundworm that can cause a skin irritation known as “nutria itch” or “swimmer’s itch.” This parasitic dermatitis presents as itchy rashes. While direct aggression from nutria is uncommon, they may bite if they feel threatened or are protecting their young. Such bites can inflict deep wounds and carry an infection risk, including rabies, although this is rare.
Ecological and Infrastructural Damage
Nutria threaten ecosystems and human infrastructure through their feeding habits and burrowing activities. They consume up to 25% of their body weight daily, feeding on the roots, rhizomes, and stems of aquatic and semi-aquatic vegetation. This intense herbivory destroys large areas of wetland vegetation, converting marshes into open water. Such destruction leads to soil erosion and loss of habitat for native wildlife.
Their feeding also extends to agricultural crops, causing losses. Beyond vegetation, nutria burrow into banks and levees, creating tunnels. These burrows weaken the structural integrity of levees, dikes, and roads, leading to cave-ins, erosion, and potential flooding. The undermining of these structures can necessitate costly repairs and threaten water management systems.
Safe Interaction and Prevention
Observing nutria from a distance is advisable; direct contact should be avoided. Do not feed these animals, as this encourages them to approach humans. If a nutria appears sick or injured, contacting local animal control or wildlife authorities is appropriate.
To prevent property damage, securing garbage and fencing off gardens can deter nutria. Fences should be at least four feet tall and extend at least six inches underground to prevent burrowing beneath them. Protecting wooden structures or trees near water bodies with sheet metal shields prevents gnawing damage. In areas where nutria are considered an invasive species, reporting sightings to wildlife agencies assists in their management.