일반명 : 사향쥐(머스크랫 / Muskrat or Musquash
학명 : Ondatra zibethicus

원산지 : 북미(North America)

The muskrat or musquash (Ondatra zibethicus), the only species in genus Ondatra, is a medium-sized semi-aquatic rodent native to North America, and introduced in parts of Europe, Asia, and South America. The muskrat is found in wetlands and is a very successful animal over a wide range of climates and habitats. It plays an important role in nature and is a resource of food and fur for humans, as well as being an introduced species in much of its present range.

The muskrat is the largest species in the arvicoline subfamily; which includes 142 other species of rodents, mostly voles and lemmings. Muskrats are called "rats" in a general sense because that they are medium-sized rodents with an adaptable lifestyle and an omnivorous diet. They are not, however, so-called "true rats", that is members of the genus Rattus.

An adult muskrat is about 40 to 60 cm (16 to 24 inches) long, almost half of that tail, and weighs from 0.7 to 1.8 kg (1.5 to 4 lb). That is about four times the size of the brown rat (Rattus norvegicus). Muskrats are much smaller than beavers (Castor canadensis), with whom they often share their habitat. Adult beavers weigh from 14 to 40 kg (30 to 88 lb). The nutria (Myocastor coypus) was introduced to North America from South America in the early twentieth century. It shares the muskrat's habitat but is larger, 5 to 10 kg (11 to 22 lb) and its tail is round, not flattened. It cannot endure as cold a climate as can the muskrat and beaver, and so has spread only in the southern part of their ranges in North America (Caras 1967, Nowak 1983).

Muskrats are covered with short, thick fur which is medium to dark brown in color with the belly a bit lighter. The fur has two layers, which helps protect them from the cold water. They have long tails which are covered with scales rather than hair and are flattened vertically to aid them in swimming. When they walk on land the tail drags on the ground, which makes their tracks easy to recognize (Caras 1967, Nowak 1983).

A Muskrat skull

Muskrats spend much of their time in the water and are well suited for their semi-aquatic life, both in and out of water. Muskrats can swim under water for up to 15 minutes. Their bodies, like those of seals and whales, are less sensitive to the build up of carbon dioxide than those of most other mammals. They can close off their ears to keep the water out. Their hind feet are semi-webbed, although in swimming the tail is their main means of propulsion (Voelker 1986).