Sydney Anderson

Zoogeography of the Montane Mammals of Colorado

In Colorado the distribution of montane or boreal habitats is at present closely-associated with the local climate produced by the mountains. Peculiarities of this habitat are high precipitation, both in winter and summer, cool temperatures, a continuous water supply and a coniferous forest. Certain mammals are more or less restricted in geographic range, in this part of the continent, to the mountains.nnIn Pleistocene time the distribution of boreal habitat and hence of boreal mammals has undoubtedly fluctuated widely with the advances and retreats of continental and alpine glaciers. The contemporary pattern of distribution is, at least in part, a result of the most recent major glacial advance and retreat which took place in the Wisconsinan Age. It seems probable to us that most contemporary subspecies have differentiated in late Pleistocene time; otherwise the frequent correspondence of their ranges with current topographical and ecological features, which stem from late Pleistocene events in many cases, seems inexplicable. In the western United States the Boreal Zone is found at higher and higher elevations as one proceeds southward until it is scattered on isolated mountain peaks. The presence of isolated populations of boreal mammals on some of these mountains is evidence of a former displacement southward and downward in altitude of the Boreal Zone in a glacial age, presumably the Wisconsin, and subsequent elevation of the Boreal Zone in altitude and latitude in an ensuing interglacial interval, presumably the Recent. These southern, marginal populations …

Noteworthy Records of Harvest Mice in México

Since the publication of Hoopers review of Latin American harvest mice (Misc. Publ. Mus. Zool., Univ. Mich., 77: 1–255, 1952) collectors from the Museum of Natural History, University of Kansas, have obtained specimens of Reithrodontomys mexicanus mexicanus and of two subspecies of Reithrodontomys microdon from Mexico that add to our knowledge of the distribution of these mice. Financial assistance from the National Science Foundation and the Kansas University Endowment Association made the collection of these specimens possible.nnReithrodontomys mexicanus mexicanus (Saussure).—Only two specimens of this subspecies have been reported from Tamaulipas, both from Rancho del Cielo, 5 mi. NW Gomez Farias (Hooper, op. cit. : 144; Goodwin, Amer. Mus. Novit., 1689: 11, 1954). On March …

An Additional Record of Mustela erminea from Utah

In the night of September 10, 1954, I trapped a male ermine, Mustela erminea muricus (Bangs), one-half mile east of Soldier Summit, in Wasatch County, Utah. I had set 42 hardware-cloth, 2½″ x 2½″ x 10″ live-traps and 45 Museum Special mouse-traps in grass along a moist swale and near head-high thickets …