James Pershing Gilligan 
Wild Animals of the Rockies 
With a List of Mammals found in Rocky Mountain National Park (Illustrated Edition)

Among the frequent questions by visitors to the Rocky Mountain region are those pertaining to the wild animals. What animals are found here? How can they be identified? What are the wildlife problems of the high country? These are common queries which this booklet attempts to answer.

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.