Muskrats are semi-aquatic rodents common across North American wetlands, and introduced in parts of Europe and Asia. These adaptable creatures thrive in environments with still or slow-moving water, such as marshes, ponds, lakes, and streams. Their diet is central to their survival and significantly shapes the wetland ecosystems they inhabit.
Primary Plant-Based Diet
Muskrats are primarily herbivores, making up approximately 95% of their diet. They consume a variety of aquatic and semi-aquatic vegetation, including roots, stems, leaves, and seeds. Common food sources include cattails (a favored food item, with muskrats consuming all parts), sedges, bulrushes, water lilies, and pondweeds. They can also eat agricultural crops like corn, sugarcane, rice, and carrots if these are available near their aquatic habitats.
Supplemental Animal-Based Diet
While primarily plant-based, muskrats are opportunistic omnivores, consuming animal matter when plant food is scarce. This supplemental diet typically includes small aquatic animals such as freshwater mussels, crayfish, fish, frogs, and small turtles. This is more common when plant-based foods are less abundant or during certain seasons. Heavy reliance on animal prey indicates challenging times.
Unique Feeding Behaviors and Adaptations
Muskrats have adaptations for aquatic feeding. Their large, chisel-like front incisors protrude ahead of their lips, allowing underwater cutting and chewing without ingesting water. Their lips can seal tightly behind these teeth, preventing water from entering their mouths. Muskrats often create “feeding platforms” or “push-ups”—mounds of vegetation or mud built in the water—where they can safely eat, especially during winter when these structures provide a space above or just below the ice. They are also capable swimmers, holding their breath underwater for 12 to 17 minutes while foraging.
Ecological Role and Impact of Their Diet
Muskrat feeding habits noticeably impact wetland environments. Their extensive consumption of vegetation can create open water areas in dense marshes, benefiting waterfowl and other aquatic birds by providing clear spaces for swimming and nesting. This increases habitat diversity and can control invasive plant species like hybrid cattails. However, when muskrat populations become large, their intense foraging can lead to “eat-outs,” where vegetation is completely removed, potentially taking years for the area to recover. Their burrowing and feeding activities can also damage human-made structures like dams, dikes, and levees, and they may consume agricultural crops near water bodies.