Snow camouflage as Hugh B. Cott have echoed his observations, adding that other animals of the Arctic such as musk ox, moose, reindeer, wolverine and raven never become white "even in the coldest parts of their range". Cott noted that both animals that hunt, like polar bear and stoat, and prey animals like ptarmigan and mountain hare, require camouflage to hide from prey or from predators respectively. There is little experimental evidence for the adaptiveness of white as camouflage, though the ornithologist W. L. N. Tickell, reviewing proposed explanations of white plumage in birds, writes that in the ptarmigan "it is difficult
Ptarmigan Tunnel doors were hung across the tunnel adits during the summer of 1975. They remain open from mid-July until October 1, weather permitting. The long tunnel is a unique man-made feature in Glacier. This trail tunnel embodies exceptional qualities of landscape architecture and engineering in a pedestrian-scaled tunnel, cut through a sheer mountain wall. Ptarmigan Tunnel The Ptarmigan Tunnel was built in 1930 through the Ptarmigan Wall at an elevation of in Glacier National Park, near Many Glacier. The tunnel allows hikers to avoid a strenuous climb over very steep terrain between Many Glacier and the Belly River valley. Two opposing