White-tailed ptarmigan name "Tetrao (Lagopus) leucurus" by the Arctic explorer John Richardson in 1831. It was later determined that "Lagopus" had sufficient distinguishing features to be regarded as a separate genus and the bird became "Lagopus leucurus". Molecular studies have shown that "Lagopus" is monophyletic, with the rock ptarmigan ("Lagopus muta") and White-tailed ptarmigan being sister species. The position of the willow ptarmigan ("Lagopus lagopus") is less clear cut, it showing some genetic divergence over its wide range. The genus name "Lagopus" is derived from Ancient Greek "lagos" (λαγως), meaning "hare", + "pous" (πους), "foot", in reference to the bird's feathered legs.
Snow camouflage snow camouflage patterns. Charles Darwin mentioned the white winter coloration of the ptarmigan in his 1859 "Origin of Species": The white protective coloration of arctic animals was noted by an early student of camouflage, the naturalist Alfred Russel Wallace, in his 1889 book "Darwinism"; he listed the polar bear, the American polar hare, the snowy owl and the gyr falcon as remaining white all year, while the arctic fox, arctic hare, ermine and ptarmigan change their colour, and observed "the obvious explanation", that it was for concealment, at a time when Darwinism was at a low ebb. Later zoologists such