|Compare the photos
shown below. The animals on the left are arctic wolves (C. lupusarctos),
and the nearly all black one at right is a member of a subspecies from
farther south. Generally, the fur of a wolf tends to be heavily mottled
with various shades. Many wolves have a large, dark patch on their
back which contrasts with their dominant coat colour. Contrasting
dark and light facial markings are also common. Also occurring in
wolves is albinism, the lack of pigmentation in an animal.
However, as is the case with virtually all mammalian species, instances
albinistic wolves (with pink eyes) are very rare.
Colouration is not especially useful in classifying grey wolves, since
it is such a highly variable characteristic, even within individual packs
or litters. Regardless of the colouration of the parents, a wolf
litter can contain pups of a multitude of hues.