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.

The “sportsmen” and market hunters were taking an even greater toll with their systematic slaughter of big game animals. The small herds of mountain bison, as well as any sign of transient moose, had disappeared by 1865. Deer and elk were so plentiful and easy to kill that wagon loads of their meat were hauled from the mountains to Denver markets where they were sold for as little as four cents a pound. Probably the easiest to condemn are the hunters who, in the late 1880’s, killed hundreds of elk, plus many deer and sheep, with little effort on their frequent organized hunts of “sport.” Often the carcasses were left to rot or just the head trophy and a few choice steaks were taken from the fallen animals. The area around Estes Park was particularly noted for this irresponsible recreation. Actually the greatest reduction in animal numbers was accentuated by the actions of a few individuals and not by the concentrated efforts of all those present in the area. By 1913 elk had entirely disappeared from the Estes Park region and almost from the state. Also, during this infamous period sheep had been reduced from an estimated 4,000 in 1870 to a little over 1,000 forty years later. The mule deer, having a wider natural range, and not banding together in the summer as elk frequently do, were able to survive the hunting pressures somewhat better; however, the former abundant herds were then considerably reduced. The increase of settlements and the introduction of domestic stock further lessened the numbers by decreasing available feeding grounds.

The establishment of man in the main mountain valleys leading to the foothills was particularly important to the past and even present welfare of the rugged mountain sheep, one of the finest of all wild animals in the mountains. Wild sheep in early days always migrated through these valleys in the winter to the foothills (5,000 to 6,000 feet), where they were able to obtain bone-building minerals available in the sedimentary rocks. These minerals were not available in the high mountain granitic rocks and present evidence indicates that they are highly essential for successful and sturdy lamb crops. Man’s dwellings created an effective barrier to these animals and no longer did they make their way to the foothills each winter. This situation probably weakened the breeding stock. In addition, there were other declining factors such as hunting and in particular, the grazing of domestic sheep on former wild sheep ranges. This not only reduced available forage for wild sheep, but also introduced certain diseases of domestic sheep into the flocks. Sheep scabies reached epidemic proportions in the late 1800’s, wiping out hundreds of wild bighorn.