CHAPTER XV. 
Carnivores,— continued. 
The Dog Tribe. 
Family CANIDS. 
Under the general title of Dogs may be included all the animals commonly 
known as wolves, jackals, foxes, and wild dogs, together with the various breeds of 
domestic dogs. These collectively constitute the family Canidce, and form a group 
in some respects intermediate between the Carnivores treated in the two preceding 
chapters, and those described in the three succeeding ones. The Dog family must 
always have an especial interest, since it includes the animals which have become 
more thoroughly the friends and companions of man than any other creatures. The 
origin of the domestic dogs is, however, shrouded in the mist of antiquity, and it 
is still an open question whether the various breeds are descended from a single 
wild stock, or whether they are the product of several species. 
The Dog family, as thus constituted, forms, at the present day, a compact and 
well-defined group, the wild members of which cannot be confused with those 
of any other. The whole of them are characterised by their long and pointed 
muzzles, their moderately long tails, and their perfectly digitigrade feet, furnished 
with blunt, nearly straight, and non-retractile claws. Then, again, all the dogs 
have but four toes on the hind-feet, while, with the exception of the African 
hunting-dog, the number of toes on the fore-feet is five, of which the first, or 
innermost, is shorter than either of the others, and does not touch the ground. 
The limbs, although varying in relative length, are never so short in proportion to 
the body as is the case in so many of the Civet family. The ears are pointed and 
erect, but vary greatly in length in the different groups. Such are some of the 
chief external characteristics of the dogs, but, in order to understand their distinc¬ 
tion from other families of Carnivores, it is essential to pay attention to the skull 
and teeth. In all dogs the skull, as shown in the figure on p. 352, is characterised 
by its elongated muzzle and the large number of teeth with which it is furnished; 
in both of which respects it is widely different from the skull of the cats. On the 
under-surface of the hinder part of the skull the tympanic bulla is inflated and 
bladder-like, although it is not divided into two chambers by a complete septum. 
This part of the skull serves, therefore, to distinguish the dogs from the 
Carnivores yet mentioned, with the exception of the hyaenas. From the hyaenas, 
as well as from the cats, the dogs are readily distinguished by the number 
and structure of their teeth. With but few exceptions, the total number of 
their teeth is 42, or two more than the true civets; the series consisting of 
