Muskrats can be devastating to the banks of lakes and dikes due to their burrowing. By digging for roots and in constructing dens, muskrats weaken and undermine the integrity of banks and dikes. The burrows eventually collapse and further erode the banks. These tunnels can also be dangerous to people walking the banks if they happen to break through the surface and fall into one endangering ankles and legs.
Muskrats (Ondatra zibethicus) resemble large field mice with none of the offensive traits or habits of the common rat. They weigh about three pounds, have bead like eyes, and their ears nearly concealed in dense fur. The hind feet are quite large, and while not webbed, have stiff hair between the toes, which aid in swimming. The tail flattened on the sides and serves as a rudder. Most muskrats have long, dark, reddish-brown fur on the upper parts of the body and short, silver-tipped fur underneath. Guard hairs are long and durable while the under fur is fine, soft and waterproof. This mammal is well equipped for its aquatic habitat but is awkward and at a disadvantage on land.
Two or three litters may be produced each year, but most muskrats in Indiana are born in May and June, 28 to 30 days after mating. Litters averaging about six in size are born in a shredded Muskrats are vegetarians, but if unable to secure plant foods, they will feed on carcasses of fish, frogs, and other muskrats. Nearly all plants growing in and near their water areas are eaten, but cattails are the backbone of their diet.
Food is not stored for winter use, so they must dig roots and tubers from beneath the ice, returning to their house and burrow to feed. If food sources are too far from the house, a feeding shelter called a “push-up” is built on the ice. A similar feeding platform - a raft consisting of discarded plant food - is constructed for summer use. Muskrats are vegetarians, but if unable to secure plant foods, they will feed on carcasses of fish, frogs, and other muskrats. Nearly all plants growing in and near their water areas are eaten, but cattails are the backbone of their diet.
A dense winter population feeding on roots and bulbs in a marsh or small lake may consume nearly all the roots. Upper parts decay the following spring, turning the water and soil sour so that few plants will grow in that area. This is called an eat-out, and if little water moves through it, this portion of the marsh may be unproductive for several years.
Reference: http://www.in.gov/dnr/fishwild/3368.htm
