The general superficial resemblance between the fox and many of our dogs, might well excuse the belief in a relationship.  Gamekeepers are often very positive that a cross can be obtained between a dog fox and a terrier bitch; but cases in which this connection is alleged must be accepted with extreme caution.  The late Mr. A. D. Bartlett, who was for years the superintendent of the Zoological Gardens in London, studied this question with minute care, and as a result of experiments and observations he positively affirmed that he had never met with one well-authenticated instance of a hybrid dog and fox.  Mr. Bartlett’s conclusions are incontestable.  However much in appearance the supposed dog-fox may resemble the fox, there are certain opposing characteristics and structural differences which entirely dismiss the theory of relationship.

One thing is certain, that foxes do not breed in confinement, except in very rare instances.  The silver fox of North America is the only species recorded to have bred in the Zoological Gardens of London; the European fox has never been known to breed in captivity.  Then, again, the fox is not a sociable animal.  We never hear of foxes uniting in a pack, as do the wolves, the jackals, and the wild dogs.  Apart from other considerations, a fox may be distinguished from a dog, without being seen or touched, by its smell.  No one can produce a dog that has half the odour of Reynard, and this odour the dog-fox would doubtless possess were its sire a fox-dog or its dam a vixen.

Whatever may be said concerning the difference existing between dogs and foxes will not hold good in reference to dogs, wolves, and jackals.  The wolf and the jackal are so much alike that the only appreciable distinction is that of size, and so closely do they resemble many dogs in general appearance, structure, habits, instincts, and mental endowments that no difficulty presents itself in regarding them as being of one stock.  Wolves and jackals can be, and have repeatedly been, tamed.  Domestic dogs can become, and again and again do become, wild, even consorting with wolves, interbreeding with them, assuming their gregarious habits, and changing the characteristic bark into a dismal wolf-like howl.  The wolf and the jackal when tamed answer to their master’s call, wag their tails, lick his hands, crouch, jump round him to be caressed, and throw themselves on their backs in submission.  When in high spirits they run round in circles or in a figure of eight, with their tails between their legs.  Their howl becomes a business-like bark.  They smell at the tails of other dogs and void their urine sideways, and lastly, like our domestic favourites, however refined and gentlemanly in other respects, they cannot be broken of the habit of rolling on carrion or on animals they have killed.

This last habit of the domestic dog is one of the surviving traits of his wild ancestry, which, like his habits of burying bones or superfluous food, and of turning round and round on a carpet as if to make a nest for himself before lying down, go far towards connecting him in direct relationship with the wolf and the jackal.