The muskrat or common muskrat [1] (Ondatra zibethicus) is a medium-sized semiaquatic rodent native to North America and an introduced species in parts of Europe, Asia, and South America. The muskrat is found in wetlands over various climates and habitats.

Muskrat dens are found above the high-water line (this may still be 4–5 ft. below ground level). The den is usually only a bit bigger than the tunnel that leads to it, often 6–8″ wide. A small air shaft at the top connects it to the surface; it’s often “screened” with loose twigs or plants.

Erosion due to muskrat burrows and dens may cause cave-ins and the collapse of some structures. The economic impact can be substantial to aquaculture facilities, if levees or water sources are impacted. Muskrats can carry and transmit several infectious diseases to people.

In dams, dikes, and banks, muskrats tunnel upward from below the water surface into the soil to make dens that remain dry (Fig. 2 and 4). Bank dens range from a short tunnel leading to an enlarged nest chamber, to a long, complex system of chambers, air ducts, and entrances.

When in a stream habitat, muskrat burrow into the banks to create dens. One or more entrances are hidden underwater and lead to chambers located above the waterline. They excavate channels or runways in shallow water leading from den entrances for ease of mobility.

2025年1月9日 · The dense underfur traps air, providing both insulation and buoyancy. Muskrats’ large hind feet, fringed with stiff bristles and partially webbed, are used as oars when swimming, with the tail serving as a rudder. They can stay submerged for up to 20 minutes and swim as fast as 5 km (3.1 miles) per hour.

2023年12月18日 · Muskrats also commonly occupy abandoned beaver lodges or bank dens. The principal cause for concern is the potential damage to ponds and lake impoundments. Damage occurs from muskrat burrowing and tunneling activities that …

In marshes, ponds, and other water areas east of the Cascade mountains, prominent muskrat lodges are sure indicators of a present muskrat population. Look for entrances into their bank dens along dams, dikes, and stream banks, particularly west of the mountains.

2019年8月30日 · Musk is secreted on logs or other defecation areas, around houses, bank dens, and trails on the bank to mark the area. The muskrat has an upper and a lower pair of large, unrooted incisor teeth that are continually sharpened against each other and are well designed for gnawing and cutting vegetation.

2021年1月22日 · Muskrats typically build dens of either underground burrows or vegetation domes in farm ponds, streams, ditches and lakes with stable water levels and abundant aquatic vegetation. Both underground burrows and vegetation domes will have underwater entrances.