Ondatra zibethicus spatulatus (Osgood). Northwest Muskrat, Ki fa ' - lûk (Mackenzie Eskimo). 

Common throughout the whole Mackenzie basin . Observed Muskrats in the west branch of Mackenzie delta nearly to Tent Island, and in the east branch up to Toker Point, both points being well north of the tree line. On the southeast end of Richard Island, September 17th, 1909, I killed twelve Muskrats in a grass-bordered slough channel. Several rat-houses here were built of heaped-up grass-stems, moss, and mud on the edge of open water; all houses rather small, not over eighteen inches above water and two and a half or three feet across. 

Muskrats were fairly common in small lakes near Horton River, from ten to forty miles south of Langton Bay. In October, I saw several muskrat holes in the ice, two or three inches in diameter. They were covered by little bunches of grass on top of the ice encircling the hole, and were kept open all the time. I saw only one rat-house near shore built up about one foot up top above water. Muskrats have become fairly common on the east side of Great Bear Lake within the past few years, according to Mr. Joseph Hodgson, a well-informed trader of the Hudson Bay Company. The Muskrat apparently does not go much east of the Coppermine River along the Arctic coast. Throughout the Indian and Eskimo country the Muskrat is considered delicious eating. Mr. Maxfield Hamilton , the Hudson Bay Company's agent at Smith's Landing, obtained an albino skin in the spring of 1908, the second one he had seen out of one or two hundred thousand rat skins handled.