The Arctic wolf (Canis lupus arctos), also known as the white wolf or polar wolf, is a subspecies of grey wolf native to the High Arctic tundra of Canada’s Queen Elizabeth Islands, from Melville Island to Ellesmere Island. Unlike some populations that move between tundra and forest regions, Arctic wolves spend their entire lives north of the northern treeline. Their distribution to south is limited to the northern fringes of the Middle Arctic tundra on the southern half of Prince of Wales and Somerset Islands. It is a medium-sized subspecies, distinguished from the northwestern wolf by its smaller size, its whiter colouration, its narrower braincase and larger carnassials. Since 1930, there has been a progressive reduction in size in Arctic wolf skulls, which is likely the result of wolf-dog hybridization. SOURCE: WIKIPEDIA