158 Mammals of Eastern Asia 
sist of mussels, snails, and crabs, which the heavy teeth are well 
adapted to crush. 
THE DOGS, WOLVES, FOXES (FAMILY CANID^) 
All the members of this family have a typically dog-like 
appearance except the odd-looking Raccoon Dog, Nyctereutes, 
which because of the large dark patches surrounding its eyes 
somewhat resembles a Raccoon. 
The Dogs are long-nosed, slender- footed, lightly built run- 
ning animals in which the canine and shearing teeth are strongly 
developed and are followed normally by one large and one small 
crushing molar. The senses of smell and hearing are especially 
acute, and of sight somewhat less so, although if objects move 
they are instantly perceived. 
Five genera occur in eastern Asia: Arctic Foxes, Alopex, 
True or Red Foxes, Vulpes, Wolves and Jackals, Cams, Asiatic 
Wild or Red Dogs, Cuon, and Raccoon Dogs, Nyctereutes. 
There are 5 or more pairs of nipples. Large litters may be 
produced. In the case of a domestic Dog recently, 23 pups were 
born at a single birth, and 10 more at the next birth. 
The Arctic Fox, Alopex lag opus, is slaty brown, with chest- 
nut-brown ears and whitish underparts in summer ; it becomes 
pure white in winter. A bluish gray variety found in some areas 
is the much prized Blue Fox of the fur trade. The Arctic Fox is 
a comparatively small-sized Fox, the length of the head and 
body about 20 inches, of the tail about 10 inches. These Foxes, 
the most northerly of all the Foxes, are found in the arctic 
regions all around the world. In eastern Siberia they have been 
reported among other places from the lower Kolyma River, 
which empties into the Arctic Ocean, from Peginski Gulf, 
Marcova, and the Anadyr River. 
The True or Red Foxes, genus Vulpes, are distinguished 
from the next genus, Cams, by the more flattened forehead, by 
the sharper cutting edges of the teeth, and by a deep, scent- 
