Through our lake and pond management activities we frequently face nuisance muskrat problems. Specifically in residential neighborhoods and business campuses, trapping muskrats can be a public relations nightmare. Fortunately, we’ve found a way to keep “rat” populations controlled in the vast majority of the lakes and ponds we manage without constantly trapping the creatures.
Understanding the Muskrat Species
Muskrats (Ondatra zibethica) are large rodents with dense thick brown fur. Their bellies are a lighter color, usually a shade of gray. The head and body of adults may be up to 16 inches long and weigh about 4 to 5 pounds. The semi-aquatic creatures prefer slow-moving or still water and eat primarily vegetation. If aquatic vegetation is limited they will eat grass or other terrestrial vegetation. A female can have up to 5 litters per year with 5 – 10 young per litter.
The Problem with Muskrats
Muskrat populations could potentially explode to an unmanageable level. Their dens and burrows can weaken a shoreline causing failure in lake dams or dangerous conditions for walking or mowing. Muskrats also have a tendency to stir up bottom mud, which limits sunlight penetration through the water, reducing natural fish food production.
The Old Solution to ridding your Lake of Muskrats
Generally there is a negative stigma that exists with trapping animals. Most parents find it unfavorable to expose their kids to the retrieval of dead animals from man-made traps, especially if the family has pets of their own. However, trapping can be effective. Success often depends upon setting many traps at once, and if suitable habitation exists, trapping often has to be repeated regularly. Since muskrats are most active at night, traps need to be checked early in the morning. Sometimes trapping is the most cost-effective control method, and either the client is impatient or negative public reaction isn’t an issue. Yet, another issue with trapping is the likelihood of catching non-target species. Dick Randall, former Supervisor of the Animal Damage Control Program says, "For each target animal I trapped, about two unwanted individuals were caught. Because of trap injuries, these non-target species had to be destroyed." (https://www.mspca.org/animal_protection/about-leg-hold-traps/)
A New Approach to ridding your Lake of Muskrats
After trying different control methods, we stumbled upon one that works and does not upset nearly as many people - diligently collapsing muskrat burrows. We found that using this method we would have been able to control muskrat populations in about 80% of the situations we previously faced.
Using a simple wood fence post about 2 inches in diameter as a tool, we walk shorelines seeking soft spots that are likely muskrat dens or burrows. With this inexpensive tool and a little muscle, we can achieve our objective of eliminating damage without offending nearby residents.
Near the water’s edge, muskrats enter the burrow under the surface of the water. They hollow out an area underground, often making a “U-shaped” burrow. A “worn” path leading from open water to the underwater entrance of the burrow may be noticeable. Once we find a soft spot on the pond bank we take our tamping device and pound the ground to completely collapse the burrow. Repeat visits to manage the burrows is recommended, tough ground can be difficult to break through in one attempt. We find that collapsing the burrows monthly will almost always control the muskrat population in 6 months or less. We collapse the burrows only when new ones are discovered, and once collapsed, we will fill in the holes with compacted soil.
We believe the success in collapsing burrows is due to reducing the survival of the muskrat young. We expect part of the control is because the adult “rats” are pestered and move elsewhere so they won’t be harassed. Since muskrats can move several miles looking for suitable habitat, maybe they will stay away. This approach allows us to determine which burrows are active and our trapping is simpler and much more effective. A conibear-type trap set underwater is considered the most humane control method.
Leaving nuisance-level populations of muskrats alone is simply not an option. These rodents can create unfathomable damage. A pond dam riddled with burrows can leak or break, which can destroy valuable property downstream. An animal or human can break a leg stepping into a hollowed out underground burrow. A lawn mower or tractor can get stuck or even overturn if a wheel falls through the ground into a den or burrow. This muskrat control method has made our life easier. We save time and aggravation by not having to explain our actions to irate lakeshore residents. We’ve resolved potential conflicts among neighbors; some of which insist on getting rid of the “rats” and some who insist Mother Nature’s creatures should not be destroyed. Furthermore, we get a good upper body workout.