Foxes are elegant creatures, renowned for their cunning and grace. You may even think they look a little like dogs, with their long bodies and pointed snouts. Foxes are a common sight in many areas, and they often live in areas populated by humans, and therefore also by dogs. If foxes and dogs come into contact, is it possible for them to breed? Read on to find out more!
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The evolution of dogs and foxes
Foxes and dogs both belong to the family Canidae, but their evolutionary pathways split off long ago. Heading down the evolutionary pyramid, dogs belong to the genus Canis, whereas foxes are categorised into several other genera, with the most common fox species found in the Vulpes genus. This genetic divergence of the two groups occurred over 7 million years ago! Other animals found in the Canidae family include coyotes, jackals and of course wolves (the original Canis).
It is a widely-held myth that foxes and dogs are closely related. This may be because certain dog breeds look somewhat fox-like, such as the Shiba Inu and even the long-haired Chihuahua. In fact, foxes are physically quite different from dogs; being generally smaller and with much flatter skulls, longer bodies and shorter legs. They are also very diverse genetically.
With both species evolving away from each other over these millions of years, it is unsurprising that they are now genetically very different from each other. Although members of the same family, this includes a huge range of animals and doesn’t imply a particular genetic closeness except at a very generalised level.
As dogs and foxes belong to different genera, this means their genetic material is not hugely similar to each other’s. Foxes have 34 chromosomes, whereas dogs have 78 – quite a difference! This massively affects their breeding potential. For two individuals to successfully mate and produce viable, fertile offspring, they need to be genetically similar. Having a vast difference between chromosomal make-up is certainly not ideal, and makes a viable hybrid extremely unlikely.
There are no genetically verified dog-fox (“dox”) hybrids on record. However, there are some un-verified anecdotal reports, usually involving a male fox and female dog in captivity.
The Grosvenor Museum in Chester, UK, has a supposed ‘dox’ on display. It is said to be from a male fox mating with a female dog on a canal boat! However, it has not been genetically examined as to its genetic make-up and there is no evidence to support the tale.
In the 19th Century, Wilhelm Niemeyer, director of Hannover Zoo gives an account of a litter of dog-fox hybrids bred under captive conditions at the zoo. Four offspring were produced, which all died within a few days of birth. Another zoo example involves an account in 1932 by the director of Hellabrunn Zoo in Munich, who crossed a female Spitz dog with a common fox. The accounts appear genuine, but there is no lasting evidence that the hybrid was successful as described.
There are many other anecdotal accounts in literature and history of dogs mating with foxes and producing viable offspring, however none of these have been scientifically verified as accurate and most are probably embellished or pure fiction.
Are any dog hybrids possible?
In certain cases, animals of different species can mate, and produce offspring. However, even in genetically compatible species, these offspring are often infertile. Hybrids are usually only successful if the two species are genetically close enough: this usually means having similar numbers of chromosomes. Dogs, which have 78 chromosomes, have been known to mate with other members of the Canis genus, such as wolves (their original ancestor species), dingoes (probably a feral version of our domestic dogs!), jackals (78 or 80 chromosomes) and coyotes (78 chromosomes). These species are much closer genetically to dogs than foxes are.
There has also been one confirmed case of a dog-Pampas Fox hybrid which has got a lot of attention in the media recently. However, the Pampas Fox is a very different genus and species to the European Fox (Lycalopex gymnocercus rather than Vulpes vulpes) and is more genetically similar to dogs, making a hybrid genetically possible.
What would happen if a fox tried to breed with a dog?
If a fox and a dog mated, there would almost certainly be no successful pregnancy. In fact, the only likely complication is injury to one or both parties. Foxes and dogs are more likely to be competitors than live harmoniously, and have no reason not to defend themselves and their home environments from each other.
Although there are some anecdotal reports of a successful ‘dox’ hybrid through the mating of a European fox and a dog, there is no true evidence of this. In fact, the mating of a fox and dog is highly unlikely due to large genetic diversity between the two species. European Foxes and dogs are just too genetically dissimilar for a successful mating.
Although of course if anyone knows of any solid evidence, we’d love to see it…