The muskrat (Ondatra zibethicus) is a semi-aquatic rodent found across North American wetlands. While broadly considered an omnivore, approximately 95% of its diet consists of vegetation. The remaining small portion of animal matter provides a nutritional balance that allows them to thrive. Understanding what they eat requires a look at their primary plant sources, the supplemental protein they consume, and the specific behaviors they use for foraging.
The Core Diet of Aquatic Vegetation
The composition of a muskrat’s diet is heavily influenced by the plants available in its marsh, pond, or stream habitat. Their digestive system is specifically adapted to process green vegetation. These rodents primarily target the most nutrient-dense parts of aquatic plants, often ignoring the less palatable outer stalks and leaves.
Commonly consumed species include cattails, rushes, sedges, and water lilies. Muskrats prefer the basal parts, roots, and rhizomes of these plants, which contain higher concentrations of stored carbohydrates and energy. Their feeding habits involve selectively clipping stems and digging for underground portions, a process that can significantly alter the local distribution of plant life in a wetland.
The Role of Animal Matter in Their Diet
Although muskrats are primarily herbivorous, they are opportunistic foragers who supplement their diet with animal protein. This small fraction of their food intake establishes them as omnivores. The consumption of animal matter provides a valuable source of nitrogen, which is often a limiting nutrient for mammals subsisting on aquatic plants.
Specific prey items are typically slow-moving aquatic organisms readily found in their environment. These include freshwater mussels, crayfish, and snails. Muskrats also consume small vertebrates like frogs, small fish, and occasionally turtles. In times of scarcity, they may scavenge carrion, such as dead fish or the carcasses of other muskrats, demonstrating a flexible feeding strategy.
Feeding Behavior and Seasonal Shifts
Muskrats exhibit distinct feeding behaviors that maximize foraging efficiency and adapt to changing seasonal conditions. A common sight in marsh habitats is the presence of “feeding platforms,” which are small, dome-shaped piles of cut vegetation used as temporary dining spots. These structures are often built on logs, rocks, or floating plant debris, allowing the muskrat to remain partially concealed and dry while consuming their meal.
The colder months necessitate a significant shift in foraging strategy, as muskrats do not store food for the winter like beavers do. Instead, they must remain active, often tunneling beneath the ice to access submerged roots and rhizomes. They may also construct “push-ups,” which are small shelters made of vegetation placed over a hole in the ice, providing a temporary breathing hole and a protected place to consume food. When aquatic vegetation declines, the opportunistic consumption of mussels and other animal matter becomes a more significant means of sustaining themselves.