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
Winter white dwarf hamster sungorus sungorus". Today Winter white dwarf hamsters and Campbell's dwarf hamsters are considered separate species with the Winter white officially known as "Phodopus sungorus". The coat of the Winter white hamster is less woolly than that of Campbell's dwarf hamster, and apart from the normal colouring, they can be coloured sapphire, sapphire pearl, or normal pearl. The head length of the Winter white hamster is 70–90 mm, the length of the tail is 5–15 mm, and the hind legs are 11–15 mm. The body weight changes dramatically throughout the year. It is at its lowest during the winter. In males,