heir
prey with greater facility, it is not surprising that we should find the
majority of polar animals coloured white. As I remarked, the polar area
contains a very distinct set of species; most of them, however, range
beyond the confines of the Arctic Circle. It is therefore scarcely
justifiable to raise this Arctic area into a distinct zoological region
equivalent to the great zoogeographic regions, which have been
established by Sclater and Wallace, though we might, with Dr. Brauer,
look upon it as a sub-region.

There are six typical Polar Land-mammals, one of which, the Polar Bear,
is semi-aquatic. The Reindeer (_Rangifer tarandus_) occurs upon almost
all the polar lands, and it has often been a source of speculation in
what manner it has reached such remote islands as Spitsbergen and Novaya
Zemlya--the former of the two being so remote from a continent. There is
no doubt that Reindeer are great wanderers, owing to the difficulty of
finding sufficient food-supply for the large herds in which they are
accustomed to travel; and for this reason they can cross, and have been
known to cross, distances of from ten to twenty miles on ice. The
Behring Straits, when frozen over in winter, is frequently traversed by
them. But I quite agree with Dr. Brauer (p. 260) that it is impossible
to account for their presence in Spitsbergen by an immigration from
either Novaya Zemlya, Greenland, or Scandinavia, under the present
geographical conditions. The seas between the former island and the
other land-masses referred to are rarely entirely frozen over. Even if
this should occur, the distances between Spitsbergen and Greenland,
Novaya Zemlya, or Scandinavia are so great, that a migration across ice
is quite excluded from the range of possibilities, since Reindeer could
not subsist without food during the time it would take to travel from
one to the other. The manner in which it did reach Spitsbergen and
Greenland will be discussed more fully below, and I will therefore
proceed to mention the other Arctic mammals.

One of the most important and most typical species is the Polar Bear
(_Ursus maritimus_), the greater part of whose life is spent on the ice
and in the sea. The fact that its favourite nourishment consists of
seals proves its excellent and keen faculties of sight and hearing, and
its facility in swimming. But it is not a dainty feeder, and lives upon
almost all animals which come within its reach; birds, land-mammals, o