Nutria are large, semi-aquatic rodents native to South America, introduced to other regions primarily for fur farming. They have since established populations in various parts of the world, including North America, Europe, and Asia. Their feeding habits significantly influence the ecosystems they inhabit, leading to considerable changes in aquatic and wetland environments.
Primary Food Sources
Nutria are primarily herbivorous, consuming a wide array of plant materials found in and around aquatic habitats. They commonly feed on emergent and submerged aquatic vegetation such as cattails, bulrushes, and cordgrasses. They also consume water hyacinth, pickerelweeds, arrowheads, and flatsedges. These rodents often target the succulent basal portions of plants, including roots, rhizomes, and tubers.
They possess strong incisor teeth and dexterous forepaws, which they use to excavate and manipulate food items. Nutria consume approximately 25% of their body weight in vegetation daily. Beyond natural vegetation, nutria also consume agricultural crops. Common agricultural targets include sugarcane, rice, corn, milo, alfalfa, wheat, barley, oats, peanuts, and various vegetables.
Impact of Their Feeding Habits
Nutria’s intensive feeding habits lead to significant environmental degradation and economic losses. Their consumption of plants, particularly roots and rhizomes, results in “eat-outs”—large barren patches where vegetation is completely removed. This foraging contributes to the loss of native marsh vegetation that helps hold wetland soils together. The removal of this vegetation can convert healthy marshes into open water habitats, accelerating coastal erosion and increasing vulnerability to flooding during storms.
The destruction of wetland plants also reduces habitat and food sources for native wildlife species, including waterfowl and muskrats. They also cause substantial damage to agricultural interests. Nutria graze on crops, leading to reduced yields and significant localized losses, particularly in sugarcane and rice fields. Their burrowing activities further exacerbate problems by weakening levees, irrigation canals, and other water control structures, which can lead to flooding and infrastructure damage.
Dietary Adaptations and Seasonal Changes
Nutria exhibit flexibility in their diet, adapting food choices based on seasonal availability, local vegetation, and water levels. As opportunistic feeders, their diet shifts to include different plant species as they become abundant.
During colder months, when above-ground vegetation is scarce, nutria rely more heavily on roots, rhizomes, and tubers. They may even consume the bark of trees such as black willow and bald cypress. This shift helps them maintain energy levels during limited resources. Although their diet is overwhelmingly plant-based, nutria occasionally consume small invertebrates like insects, freshwater mussels, or crustaceans, particularly during times of food scarcity.