Page:The New International Encyclopædia 1st ed. v. 17.djvu/237

ROCKY MOUNTAINS. 213 ROCKY MOUNTAIN SUBREGION. America is remarkably dilTuse and uniform, so tliat it is considered indivisible by any well- marked distinctions; nevertheless certain zones of life rouglily bounded by summer isothermal lines have been recognized as Uoreal, Hudsonian, Canadian, xlleglianian, Carolinian, etc., in suc- cession from north to south. These are repro- duced in the Rocky and other high I'anges of the West. The height above the general base- level at which such life-zones will be found de- pends upon the latitude. Thus at the northern extremity of the range, near the mouth of the Mackenzie, not only the sunnnits but the base of the range are within the 'Boreal zone;" but at the southern extremity in New ^Mexico, the base exhibits a Carolinian or even warmer type of fauna, and one must cjimb 13.000 or 14,000 feet to find upon the peaks Arctic weather, and Arctic plants and animals. It is in these restricted summit areas that one finds the animals peculiar to the region; in the valleys and parks there is little that is distinctive. It is only when one has risen considerably that local specialties begin to appear. Thus in a medium latitude (say Mon- tana) at about 9000 feet, one rises above the sage- brush, the Douglas fir, and the black pine, with their host of valley and plain animals, and into forests of Alpine fir, white-bark and Engel- niann's pines, which indicate a climate equiva- lent to that about Hudson Bay. Here are breed- ing snow-birds (Junco), the nut-cracker, Canada jay, kinglet, and other northerly birds. This zone extends to the timber line and forms the normal xipward limit of the wapiti, moose, and mule deer ; the grizzly and black bears ; the wol- verine, many mice, squirrels, and the smaller car- nivores that pre}' upon them. At and near the timber line one begins to find among the stunted trees and plants animals which do not come lower down, but spend their lives altogether there and upon the treeless summits above it, and these are the really characteristic mountain animals: and yet with very few exceptions (the sewellel is most conspicuous) they are the same as those of sub- arctic America generally or of the higli ranges of the Pacific Coast, or different only in specific details. Such among the larger animals are the bighorn, and the Rocky Mountain white goat (qq.v. ), The former is practically a circumpolar form, and the latter is numerous at sea-level in the far north, but is scarce in the United States. The bighorn is still to be found as far south as San Francisco Peak in Arizona. Along with these two game animals are several small ones peculiar to the heights. One of the most characteristic is the pika (Lagomiis princeps) ; another is the lemming mouse (Phenacomi/s orophihis) , an Arc- tic form that burrows in the moss of the Alpine meadows ; and a third the whistler, a marmot (Arctomys) , inhabiting these heights only toward the north. This, with a weasel, which descends in winter, when the small animals are hibernat- ing or living upon their stores in underground burrows, and when the sheep have migrated be- low the snow line in order to find browse and pasturage, constitutes the list of peculiarly Rocl<j' Mountain mammals. On the heights, however, breed certain birds, as species of ptarmigan, the rosy finches (Leucosttcte) , and an occasional golden eagle or great owl. The general list of animals of the lower levels of the Rocky Mountain region is a very long one, and includes many which are distinguished oa local or geographic races or subspecies of more widely distributed forms. The bison, pronghorii, and the white-tailed deer range throughout the valleys and climb the heights to a considerable altitude in summer, and in the north caribou are common; but the bison is extinct, the wapiti re- mains only from northwestern Wyoming north- ward, and the |ironghorn is scarce. Among the carnivores, grizzly and black bears, the pinna, wildcat, wolverine, otter, marten, lisher, long- tailed weasel, black-footed ferret, badger, striped and spotted skunks, red fox. kit fox, raccoon, and cacomixl make a long list attractive in early days to trappers. An extensive catalogue of ro- dents includes a large number of local species of mice, wood-rats and voles, the beaver ( now greatly reduced), muskrat, and several hares, one or two of which are peculiar; and many species or races of l)urrowing "gophers,' and of arboreal and terrestrial squirrels. The same juineiples apply to the birds, of which about -100 species and varieties have been recorded as occurring in the central Rocky Mountain region, of which about 250 are known to breed there. A goodly list of reptiles and batrachians and fishes nuiy be compiled, the last group distinguished by the j>redominanee of salmonoids. Several s|>ecies of the Pacific coast salmon regularly reach the Rocky Mountains bj' ascending the Columbia, Fraser, and more northerly rivers. Insects abound and this region is the headquarters of the locust tribe in America. In general it may be said that what is most peculiar in the fauna of the Rocky Mountain region has been derived from the nortli, and leads back to the Glacial period, when the pre- glaeial boreal fauna was pressed southward by the slow cooling and final refrigeration of Canada. When the ice slowly melted luider the restoration of warmer conditions a large rep- resentation of this Arctic fauna found u|K)n the summits a local continuance of the cool climate favorable to it, and has remained there, often in the south isolated upon peaks which it cannot leave, and where it has survived in limited colo- nies cut off from the north. This history (which was also that of the Coast ranges) and the bar- riers afforded by the breadth of high, dry jilains to the eastward, account for the greater likeness of the Rocky Jlountain fauna on the whole to the Pacific thaii to the Atlantic side of the continent. BiBLiOKRAPllY. United States flco<iraphicnl and Gcolopical ^iirrei/ of the Jtoclni Mounliiiiix (Washington, 18(58 et seq.) : JlcClure, Thrrr Thoumnil Miles Tlirou(]h the liocky Mountains (Philadelphia. 1869) ; Farmer. The Rcsourees of the Rocky Mountains, Mineral. flra:ing, Agrirul- tural, and Tinibcr (Cleveland, 1883) ; Ingersoll, The Crest of the Continent (Chicago, 188.')) ; Coulter. Manual of the Botanti of the Ilnekij Mountain lieqion (Xew York. ISS.-i) ; Parkman. The Oregon Trail (ib., 1880); Slialer, .Vo/iire and Man in Anicriea (ib., 1892) ; Sivers, Amer- ica (Leipzig, 1894). ROCKY MOUNTAIN SHEEP. See Bio- HORX. ROCKY MOUNTAIN SUBREGION. A zoi>geoi.'raphical siilidivi~ion of the Nearctic rcion^ embracing the mountainmis country l>c- Ueen the North American plains and the sum-