The author, a former ranger-naturalist in Rocky Mountain National Park, discovered through a visitor study in 1948 that a predominating interest of vacationers was in the wildlife of the area. Therefore, the writing has been limited to brief descriptions of the four-footed animals as they are seen in nature, with some explanation of their habits and habitat so they may be more readily located. The cover “tracks” and identification plates further this intent.
Many find it difficult to understand why they cannot see “more” animals in this rugged country. These animals are wild in the strictest sense. Many are nocturnal in habit, hiding during daylight, and others must be approached very cautiously. One satisfactory method of observing wildlife is to select a “spot” off the beaten trails and sit quietly for several hours, allowing animal life to move about in a normal manner.
A secondary purpose of this booklet is to provide a check list of all mammals known to use the National Park. Not all species listed have been collected in the area. It is hoped this will be a start toward providing an accurate, more substantial, and growing list of mammals for the Park. The scientific names of the 50 species given conform to all revisions to date. Those interested in a comprehensive discussion of individual mammals should consult such publications as Warren’s Mammals of Colorado, or Cahalane’s Mammals of North America.
An effort has been made to reduce and simplify the many common names attached to certain mammals. The most representative, and yet accurate name, has been selected for each animal for use throughout its entire area of distribution. For example, there is a large group of ground squirrels (Callospermophilus) inhabiting most western states which closely resemble one another in external features. The variety of common names given these squirrels (due to differences in locality or in minute external characters) is highly perplexing to the average person. Therefore the name golden-mantled ground squirrel, by which most of this group is known in far western states, is given for the group representative in north central Colorado, formerly known as the Say’s ground squirrel. Similar methods have been followed in limiting the names of other mammals. It is suggested that those interested in wildlife adopt one common name for each similar group of animals in an effort to standardize terminology for the multitude.
Dr. William H. Burt, Curator of Mammals, University of Michigan Museum of Zoology, has reviewed the manuscript and made many helpful suggestions. Miss Diana Wiltse, of the Ann Arbor Press, designed the cover and identification pages. I am also grateful for files of information and many photographic cuts furnished by the National Park Service. Unless otherwise indicated, photos were provided through the courtesy of Nature Magazine.
WILDLIFE OF THE LAST HUNDRED YEARS
Before the arrival of settlers in the mountain valleys of north-central Colorado in 1860, only the Ute and Arapaho Indians of the region and a few adventuresome white trappers knew the wildlife then so abundant throughout the area. They alone had observed the thousands of elk and small groups of mountain bison (buffalo) grazing the alpine meadows in the summer. Plentiful herds of mule deer roamed the valleys and forests and hundreds of flocks of wild mountain sheep fed on tufts of grass and flowers on rugged mountain slopes above timberline. Even an infrequent moose wandering down from his more northerly habitat could be seen in the lower wet meadows.
Along with these wonderful groups of hoofed animals lived the predatory, or carnivorous, animals. The powerful and vicious wolverines were common in the heavy forests of the high mountains, as were huge grizzly bears, occasional timber wolves, and cougars. The Canada lynx and mountain bobcat preyed on animals their size and smaller in the pine and spruce timber, while the red fox and rare gray fox were effective squirrel, mouse, and rabbit catchers. Pine martens chased small rodents through deeper forested regions, and they in turn were preyed on the larger carnivores. Numerous otter, mink, and weasel played in and along rushing mountain streams and clear lakes, feeding on a great variety of aquatic animals, fish, and small meadow rodents.
This scene might have remained relatively undisturbed had not white man arrived in the region. His rapid settlement and use of the area after 1870 had a startling and widespread effect on the wildlife populations in the next fifty years. Had he been satisfied to develop a small portion of the mountain country and take only sufficient food and clothing materials as they were needed from the wild species, the story might have been different. Instead, the unprecedented mountain scenery, climate, and animals attracted scores of vacationists, sport hunters, trappers, and market hunters, all anxious to profit from the newly-discovered virgin territory.
The great fur demand in St. Louis and Denver at this time attracted scores of trappers; they diligently pursued the valuable fur-bearers until, in 1915, the otters and wolverines were practically extinct in the Rocky Mountain regions of Colorado, and remain in that condition today. A few have been seen recently in the state, but they are exceedingly rare. Beaver were heavily trapped even before the settlers arrived. Mink, marten, and red fox also reached a very low ebb in population in the early 1900’s.