The voice of the isatis partakes of the barking of a dog and the yelping of a fox. Those who deal in furs distinguish two animals of this kind, the one white, and the other of a bluish ash-colour; the last are the most valuable. This difference in the colour is not sufficient to constitute two different species, for experienced hunters assured M. Gmelin that they have found in the same litter some of the young ones white and others ash coloured. The isatis inhabits the northern climates, and prefers those countries which border on the frozen sea and the banks of the rivers which fall into it. They are found in the coldest, most mountainous, and most barren parts of Norway, Lapland, Siberia, and even Iceland. These animals copulate in the month of March, and being formed like the dog they do not separate for some time. The females continue in heat from fifteen days to three weeks, and after that time they retire into the holes, or burrows, which they have previously prepared. They make several passages to these burrows, which they keep very clean, and furnish with moss for their greater convenience. The time of gestation, like that of the bitch, is about nine weeks. They litter about the latter end of May, or beginning of June, and commonly produce from six to eight at a time. Those which are yellow when first littered become white as they grow up, and those which are blackish change to an ash. When young their hair is very short. The mother suckles them five or six weeks, after which time she drives them out of the burrow, and teaches them to seek for their own nutriment. By September their hair attains the length of half an inch, and it is then entirely white, excepting a longitudinal brown streak upon the back, and another across the shoulders; it is then called _vulpis crucigera_, or the _crost fox_; but this brown cross disappears before the winter, when the whole body of the animal is white, and the hair about two inches long. In May their hair begins to fall off, and continues to do so until July, by which time they have entirely shed their coats, so that their fur is only valuable in winter. The isatis lives upon rats, hares, and birds, which he catches with as much subtlety as the fox. He plunges in the water, and traverses the lakes in search of water-fowl and their eggs: and the only enemy he has to dread in the desart and cold countries, is the glutton. As the wolf, the fox, the glutton, and other animals which inhabit the northern parts of Europe and Asia, have passed from one continent to the other, and are to be found in America; we must therefore conclude the isatis is to be met with in the New Continent, and I am inclined to believe that the grey fox of North America, which Catesby has given the figure of, may possibly be the isatis, instead of a simple variety in the species of the fox. _Engraved for Barr's Buffon._ [Illustration: FIG. 182. _Glutton._] [Illustration: FIG. 183. _Carcajou._ FIG. 184. _Kmeajou._]