Mammals of Washington are of especial interest to the naturalist because many of them are recent immigrants; much of Washington was buried under thick glacial ice until relatively recently and many of the mammals, therefore, have inhabited the area only since the ice disappeared. The evolution or development of certain subspecies, in Washington, has certainly occurred within the last few thousand years. To be able thus to date such evolutionary changes as have occurred is of course a matter both of importance and interest to zoÖlogists. The evolutionary changes in several species are relatively great. In color, for example, the bobcat in the humid coastal area of western Washington is notable for its dark coloration, whereas in the more arid area of southeastern Washington it is remarkably pale and of a different subspecies. Within the limits of the state of Washington, elevations ranging from sea level to more than 14,000 feet occur. Since different elevations have their characteristic mammals, more kinds are found in Washington than in other areas of corresponding size that lack such topographic diversity. Expressed in terms of the life-zone concept, Washington includes faunas ranging from the Upper Sonoran Life-zone to those of the Arctic-Alpine Life-zone.

The basis for a study of the mammals of Washington was laid in 1929 by W. P. Taylor and W. T. Shaw in the "Provisional List of the Land Mammals of the state of Washington." Bailey's "Mammals and Life Zones of Oregon" and "The Recent Mammals of Idaho" by W. B. Davis deal with the habits and distribution of mammals in the areas bordering Washington on the south and east, and were very useful in the organization of the present report.

The study was first planned from the taxonomic and ecologic point of view. Such a study, of necessity, involves the classification and distribution of the forms concerned. Classification has required more work than any other part of the study and has been, in a sense, the nucleus of the study. Nevertheless, as the report began to take form it was recognized that the part dealing with classification and other purely technical aspects of the paper probably would be uninteresting to the average reader. Therefore it was felt that a greater impetus to the study of the mammals of Washington would be given by reducing the taxonomic accounts to the minimum and dealing principally with the problems of distribution.

As originally planned, the present report was to be of joint authorship by Dr. Victor B. Scheffer of the United States Fish and Wildlife Service, Seattle, and the writer. The press of other work prevented Dr. Scheffer from devoting as much time as he had planned to the project. He has, however, contributed his field notes, specimens, and photographs, and in many other ways assisted in the project.

Field work on mammals of Washington was carried out by the writer from 1936 to 1940 but a decision to prepare a complete report was not reached until 1938. Intensive field work was done between 1938 and 1940. In August, 1941, the author took up residence at Berkeley, California. Drafting of the manuscript was begun at that time as a student under Professor E. Raymond Hall. War conditions and the press of other work delayed completion. Subsequently, the manuscript was put in final form at the University of Kansas.

Many persons in addition to Dr. Scheffer have given assistance in the course of this work. Dr. E. Raymond Hall, in particular, encouraged the project and gave assistance in various ways including critical attention to the manuscript. I am indebted also to Dr. Trevor Kincaid and Mrs. Martha Flahaut of the University of Washington, Dr. Seth B. Benson and Dr. Alden H. Miller of the University of California, Dr. H. H. T. Jackson of the U. S. Fish and Wildlife Service, Dr. George E. Hudson of the Charles R. Conner Museum, Mr. Burton Lauckhart of the State of Washington Department of Game, and Mr. Ernest Booth of Walla Walla College. Mrs. Peggy B. Dalquest typed and edited the several preliminary drafts of the manuscript and aided in the laboratory and field work. Thanks are due also to many others, including game protectors, hunters and trappers, who have given assistance. The names of some of them are mentioned in the following pages.

Approximately ten thousand specimens of mammals were used. In decreasing order, according to the number of specimens studied from Washington, the following collections are to be mentioned: materials obtained principally from southern Washington in the years 1939 to 1942 as a result of the interest of Miss Annie M. Alexander and Dr. E. Raymond Hall; these materials are in the University of California Museum of Vertebrate ZoÖlogy. The writer's own collection which at one time numbered 2,500 specimens was the second source. The residue, the part not destroyed by fire at the writer's home in the spring of 1942, in Seattle, now is in the Museum of Vertebrate ZoÖlogy at the University of California and the Museum of Natural History at the University of Kansas. The other collections are those of the Biological Surveys of the United States Fish and Wildlife Service, the Washington State Museum at Seattle, the Charles R. Conner Museum at Washington State College, and the Museum of Natural History at the University of Kansas. In the latter collection are some materials obtained nearly half a century ago by the late L. L. Dyche, some recently taken specimens added by reason of the provision for work of this kind by the University of Kansas Endowment Association and, as noted above, a part of the author's original collection. Selected specimens from several other collections have been used and these are indicated in the text when particular reference is made to the specimens. Most of the specimens studied were conventional study skins with skulls. In some instances skeletons, skins alone, skulls alone, or entire animals preserved in alcohol have been used.