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 (sternwheeler) Ptarmigan (sternwheeler) Ptarmigan was a sternwheel steamboat that operated in British Columbia on the Columbia River from 1903 to 1909. "Ptarmigan" was built at Golden, BC and was the last vessel built for the Upper Columbia Navig. & Tramway Co., of which Capt. Frank P. Armstrong was the principal owner and manager. "Ptarmigan"'s engines were over 60 years old, and had been originally built for a ferry crossing the St. Lawrence River. The engines had been previously installed in two other sternwheelers on the upper Columbia River, specifically the first "Duchess", and the second "Duchess". The blunt-ended bow of "Ptarmigan"