Muskrats aren’t inherently bad, but they can cause serious property damage, particularly to pond dams, levees, and shorelines. Their burrowing is the single biggest source of problems, and it can compromise structures that hold back water. At the same time, muskrats play a surprisingly important role in keeping wetland ecosystems healthy. Whether they’re “bad” depends almost entirely on where they show up and what they’re digging into.
Burrowing Damage Is the Main Problem
The chief complaint against muskrats is their digging. They tunnel into pond dams, lake shorelines, levees, and the banks of aquaculture reservoirs, and these burrows can extend from just below the waterline to about 3 feet deep. Over time, that hollowing weakens earthen structures from the inside out. A compromised pond dam can leak, erode, or in serious cases fail entirely, releasing water and sediment downstream.
Muskrats also damage floating marinas, docks, and boathouses. Steep banks are especially vulnerable because the angle makes burrowing easier. If you own a farm pond or reservoir, one early warning sign is underwater “runs” or trails visible along the bank when the water is clear. Drawing down the water level by 1.5 to 3 feet in winter can expose burrows before they become a structural threat.
They’re Actually Good for Wetlands
In natural settings, muskrats are a net positive. Their foraging, traveling, and lodge-building create small openings in dense marsh vegetation, increasing the mix of open water and plant cover. That patchwork of habitat boosts plant species diversity and attracts a wider range of wildlife. Marshes with a roughly equal ratio of open water to emergent vegetation support greater density and diversity of waterfowl and other marsh birds.
Muskrat lodges, both active and abandoned, serve as nesting and resting platforms for species including black terns, Canada geese, and occasionally trumpeter swans. Less obviously, more than ten species of reptiles and amphibians use muskrat houses, burrows, and cleared pathways for shelter, nesting, and temperature regulation. In one Illinois study, spotted turtles (a species at risk) were frequently found in deep open-water pools created by muskrat grazing, which served as cool refuges during heat and drought. So while muskrats can be destructive on your property, removing them from a natural wetland can actually degrade the ecosystem.
Disease Risks to Humans
Muskrats can carry the bacterium that causes tularemia, a serious infection sometimes called “rabbit fever.” Humans typically contract it through direct skin contact when handling or skinning infected animals, though it can also spread through contaminated water, inhaling contaminated dust, or tick and deer fly bites. The infection can affect the skin, eyes, lymph nodes, or lungs depending on how it enters the body. Eating undercooked meat from an infected muskrat can cause a throat and mouth form of the disease.
The practical takeaway: don’t handle muskrats (dead or alive) with bare hands, and don’t drink untreated water from sources where muskrats are active. For most people who simply see muskrats around a pond, the disease risk is low because it requires direct contact or contaminated water.
Why Populations Grow Quickly
Muskrats reproduce fast. After a gestation of just 25 to 30 days, females give birth to litters of 4 to 8 kits and can produce up to three litters per year. That means a single pair can generate over 20 offspring in one breeding season. They’re built to absorb high predation losses from mink, raccoons, and raptors, with mink being their most significant natural predator. In areas where predator populations are low or habitat is ideal, muskrat numbers can climb quickly enough to cause noticeable damage in a single season.
Don’t Confuse Them With Nutria
If you’re seeing a large rodent near water and wondering whether it’s a muskrat, size and tail shape are the fastest identifiers. An adult muskrat weighs about 3 to 4 pounds and measures 16 to 25 inches long, including a 7- to 12-inch tail that is flattened side to side and mostly hairless. Nutria are much bigger at 11 to 22 pounds, with round, hairy tails and distinctive white whisker patches on the muzzle. Beavers are larger still, with broad, flat, paddle-shaped tails. This distinction matters because nutria are an invasive species that causes far more ecological harm, and management strategies differ between the three.
How to Protect Your Property
If muskrats are already burrowing into a pond dam or bank, several physical barriers can discourage them without requiring lethal control.
- Riprap: Lining the bank with coarse stones 6 inches or larger in diameter, placed from 1 foot above to 4 feet below the water level, makes burrowing difficult.
- Wire mesh: Galvanized wire with 1- or 2-inch openings can be staked flat against the dam face, extending from 1 foot above to at least 4 feet below the waterline.
- Dam design: If you’re building or rebuilding a pond dam, a 3-to-1 slope on the water side, a 2-to-1 slope on the back, and a top width of at least 8 feet all discourage burrowing. Keep normal water levels at least 4 feet below the dam’s crest.
Lowering the pond level by 1.5 to 3 feet each winter exposes burrow entrances, letting you spot and repair damage early. Steeper banks invite more burrowing, so grading banks to a gentler slope is one of the most effective long-term prevention measures. For persistent problems, many state wildlife agencies offer guidance on trapping during regulated seasons.