154 MAMMALS

Central Asian mountains have two humps which are
very small, but the size of the hump, at least in the
domesticated varieties, depends very much on the
amount of food and the season of the year. The food
of these Lob-Nor camels—which are of a reddish hue,
with short ears and a grizzly muzzle—consists of the
branches and leaves of trees, which is exactly what
one would have supposed the original wild camels sub-
sisted on, judging from their anatomy.

The llamas, in the usual acceptation of the term,
include the vicunia and the guanaco, besides the domes-
ticated varieties, alpaca and llama, all of which belong
to the genus Lama. The guanaco, L. guanacus, is the
largest living representative of the genus, which in
some of its fossil allies was as large as any of the
existing camels. Like the vicunia, which is a smaller
animal, its toes are more divided than a camel’s, and .
have separate pads, while the hoofs are even more
like nails. The extinct species, however, show many
of the intermediate stages. The llama, Z. glama,
is a guanaco, bred for centuries as a beast of burden;
the alpaca, L. pacos, is a guanaco, bred for its wool.
The vicunia is practically restricted to the Peruvian
region, but the range of the guanaco extends from
the equator to the sandy deserts of Patagonia, where
it seems to be most at home. Guanacos have even
been found living at large in Tierra del Fuego. The
domesticated camel refuses to swim ; the guanaco will
not only swim in the sea, but drink salt water.

Of the next group, Swzza, there are three divisions
—the peccaries, with four toes in front and three
behind ; the pigs, with four toes in front, only two of