The houses are built in shallow water and have underwater entrances and tunnels. Muskrats also make burrows and dens in pond and lake banks. They mate in spring and summer in the north and in the winter in the south. Predators of the muskrat include man, minks, large snakes, great horned owls, river otters, and large-mouth bass. Muskrat fur is harvested by humans.
Muskrats build throughout the year.
Besides working on their unique homes, they build 'feeder huts' and 'breather huts' in the winter. The 'feeders' are huts used for eating without disturbance from predators, consisting of a roofed circular platform made of aquatic plants. The 'breathers', also called 'pushups', are made when the muskrat cuts a hole in the ice and pushes mud and sticks up through it, creating an under-ice hollow. Muskrats are considered pests by the owners of small reservoirs, since the animals can severely weaken the dams that sustain the reservoir.