I came across this pair while looking for ducks - and discovered how curious, social, and NOISY they are. They were non-stop action, bringing greens and root balls in constant fashion into a bank den which they had built on the side of a quiet pond. During the warmer seasons, they will move into beaver lodges, or tunnel into the bank of a pond. In the winter, they construct mini-versions of a beaver lodge, only crafted with with soft grasses and perhaps a few sticks. These "push-ups" don't provide much predator protection for the animal, but rather gives it a spot to get out of the water, dry off, and the dry grass helps to retain some body heat. However, these are very easily invaded by predators of muskrats such as members of the weasel family, bobcats, foxes, and coyotes. The bank dens however, are much more elaborate and provide for areas to store food, dry off, sleep, and raise young. They are generally also harder for predators to invade. Muskrats will even share a lodge with beavers (especially in winter) but if there is conflict, it is generally the muskrats that move out.