Canid Hybrid
Dogs
Canid Hybrid
Canid hybrids are the result of interbreeding between two
different members of the canine family (Canidae).
Canid interfertility
Many members of the dog family can interbreed to produce fertile offspring.
Molecular analysis indicates 4 divisions of canids:
- Wolf-like canids
including the domestic dog,
gray wolves,
coyotes, and
jackals
- The South
American canids
- Old and New World red-foxlike canids, for example,
red foxes and
kit foxes
- Monotypic species, for example,
bat-eared fox
and raccoon dog
The wolf, coyote, jackal, and domestic dog (including the
dingo) all have 78
chromosomes arranged in 39 pairs. This allows them to hybridise freely (barring
size or behavioural constraints) and produce fertile offspring. The wolf,
coyote, and
golden jackal diverged around 3 to 4 million years ago. Other members of the
dog family diverged 7 to 10 million years ago and are less closely related and
connot hybridise with the wolf-like canids: the yellow Jackal has 74
chromosomes, the red fox has 38 chromosomes, the raccoon dog has 42 chromosomes,
and the Fennec fox
has 64 chromosomes. Although the
African
Wild Dog has 78 chromosomes, it is considered distinct enough to be placed
in its own genus.
(Note: It may be that foxes cannot hybridize with dogs but, as crosses
between horses and zebras demonstrate, differences in chromosome number are not
the reason. Viable hybrids between species are possible regardless of chromosome
number differences provided the gene combination in the hybrid allows for
embryonic development to birth. Large differences in chromosome number, however,
would make hybrid bitches so poorly fertile as to be essentially sterile. Male
hybrids would be sterile due to a phenomenon called
Haldane's Rule.)
In The Variation Of Animals And Plants Under Domestication,
Charles Darwin
wrote:
- "Buffon got four successive generations from the wolf and dog, and the
mongrels were perfectly fertile together. [...] M. Flourens states
positively as the result of his numerous experiments that hybrids from the
wolf and dog, crossed inter se, become sterile at the third
generation, and those from the jackal and dog at the fourth generation. (De
la Longevite Humaine par M. Flourens 1855 page 143. Mr. Blyth says (Indian
Sporting Review volume 2 page 137) that he has seen in India several
hybrids from the pariah-dog and jackal; and between one of these hybrids and
a terrier. The experiments of Hunter on the jackal are well-known. See also
Isid. Geoffroy St.-Hilaire, Hist. Nat. Gen. tome 3 page 217, who
speaks of the hybrid offspring of the jackal as perfectly fertile for three
generations.) [...] Mr. Philip P. King, after ample opportunities of
observation, informs me that the Dingo and European dogs often cross in
Australia]]. ... Several years ago I saw confined in the
Zoological Gardens of
London a female hybrid from an English dog and jackal, which even in
this the first generation was so sterile that, as I was assured by her
keeper, she did not fully exhibit her proper periods; but this case was
certainly exceptional, as numerous instances have occurred of fertile
hybrids from these two animals. ... We have already seen how often savages
cross their dogs with wild native species; and Pennant gives a curious
account (History of Quadrupeds 1793 volume 1 page 238.) of the manner
in which Fochabers, in
Scotland, was stocked "with a multitude of curs of a most wolfish
aspect" from a single hybrid-wolf brought into that district. [...] the
jackal is prepotent over the dog, as is stated by Flourens, who made many
crosses between these animals; and this was likewise the case with a hybrid
which I once saw between a jackal and a terrier.
In Darwinism An Exposition Of The Theory Of Natural Selection With Some Of
Its Applications (1889),
Alfred Russel Wallace commented:
- "Dogs have been frequently crossed with wolves and with jackals, and
their hybrid offspring have been found to be fertile _inter se_ to the third
or fourth generation, and then usually to show some signs of sterility or of
deterioration."
(Note: this deterioration was probably the result of inbreeding among the
hybrid offspring)
Dog hybrids kept as pets are prohibited in many jurisdictions or are classed
as wild animals and must be housed in the same way as purebred wolves. For
example, hybrids of the domestic dog with the wolf, coyote, dingo, jackal, fox,
dhole, African Wild Dog, or
Raccoon dog are prohibited in the State of
Hawaii (this legislation
does not take into account the impossibility of some of the hybrids listed).
Wolf-dogs
People wanting to improve domestic dogs have sometimes bred them back to
wolves. This compensates for inbred genetic problems in domestic dogs, but
wolf-dog hybrids are dominant
in adulthood and less domesticable. Grey wolves have been crossed with wolf-like
dogs such as
German Shepherd Dogs and
Alaskan
Malamutes. Many problems occur because the owner expects them to behave like
a domestic dog and is unaccustomed to wolf-type behaviour. In parts of Europe,
the declining wolf population naturally hybridises with stray and feral domestic
dogs, resulting in mongrel
populations and further endangering the natural wolf.
There are a number of wolf-dog hybrid breeds in development, for example, the
Saarlooswolfhond breed is possibly derived from wolf-dog hybrids. The
initial hybrid offspring are generally back-crossed to domestic dogs to maintain
a domestic temperament and consistent conformation. First-cross wolf-dog hybrids
are popular in the USA, but
retain many wolf-like traits.
Dox
Contrary to popular myth, dogs cannot successfully interbreed with red
foxes. Dogs have 78 chromosomes,
but red foxes have only 38 chromosomes. This severe mismatch is a barrier to
hybridisation.
An unconfirmed female terrier/fox hybrid was reported (and later euthanized)
in the UK. British gamekeeper folklore claims that Terrier bitches can produce
offspring with dog Foxes. The supposed hybrids (known as a dox) are
natural variation in the domestic dog. There has been a reported cross between a
domestic dog and a South American fox, but the latter was a fox-like wolf and
not a true fox.
In Saskatchewan, Canada there was another reported dox, this time a female
miniature sheltie with a wild fox. There was a litter of three, but only one
survived. The surviving (a female) was sterile, and looked like an almost pure
fox, with slight variations.
In Origin of Species (1859), Charles Darwin wrote:
- The
German Spitz dog unites more easily than other dogs with foxes [...]
certain South American indigenous domestic dogs do not readily cross with
European dogs ...
Coy-dog
Coy-dogs (male coyote/female dog) can occur naturally as female coyotes are
more likely to meet male dogs than meet male coyotes. Coydogs were once believed
to be present in large numbers in
Pennsylvania
due to a declining Coyote population and a burgeoning domestic dog population.
Most supposed hybrids were naturally occurring red or blond color variations of
the Coyote or were feral dogs. The breeding cycles of dogs and coyotes are not
synchronized and this makes interbreeding uncommon. If interbreeding had been
common, each successive generation of the Coyote population would have acquired
more and more dog-like traits.
Coyotes are solitary by nature and this trait is carried across to coyote-dog
hybrids. This can result in problematical and unsociable behaviour which makes
them generally unsuited as pets. As a result, they may be abandoned or allowed
to stray and be absorbed into the feral dog or coyote population.
Coy-Dingo
Coyotes have also been crossed with Australian dingoes in zoological gardens.
Dingo hybrids
The Australian Dingo (a feral,
rather than wild, species) hybridises freely with domestic dogs. This is now so
widespread that many dingoes are now mongrels. Some dingo hybrids have been
deliberately bred as pets, but are turned loose due to behavioural problems.
These hybrids are accepted back into the wild dingo population where they breed
with pure dingoes. In some parts of Australia, up to 80% of dingoes are hybrids.
Dingoes are distinguishable from domestic dogs through
DNA and through having longer
teeth and longer muzzles.
The
Australian Kelpie
sheepdog is widely believed to be a hybrid of dingo and
Border Collie,
but this is not upheld by breed documentation.
Dogote
The mating of a male dog and a female coyote results in a Dogote. There has
been one report of a Dogote which arose from a male German Shepherd/female
coyote mating in the wild. Hybrid pups were found after a female coyote was
shot. The adult Dogotes resembled a German Shepherd in color.
Coyotes are solitary by nature and this trait is carried across to dog-coyote
hybrids resulting in problematical or unsociable behaviour.
Coy-wolf
Coy-wolves (Coyote/Wolf) have occurred in captivity or, rarely, in the wild
where the choice of same-species mates has been limited. Coyote/Red Wolf hybrids
have been found. Some consider that the American Red Wolf is not a true species
because it can hybridize with both the Grey Wolf and the Coyote; however, it is
now known that hybridization between species (in general) happens more often
than previously thought. Some consider it a Grey Wolf/Coyote hybrid and use this
argument to prevent conservation of the Red Wolf. Some hybridization occurred
when pure Red Wolves were in decline and interbred with the more numerous
Coyotes. The species boundary is often preserved by geographic or behavioural
separation, not by genetic separation.
Jackal hybrids
The Wolf and Jackal can
interbreed and produce fertile hybrid offspring. Coyote/Jackal Hybrids have also
been bred as pets by Wolf-dog enthusiasts. Dogs have been crossed with golden
jackals; however, they cannot produce fertile offspring with yellow jackals as
the latter have only 74 chromosomes compared to 78 in the dog. It is also
thought that Pharoanic
Egyptians
crossbred domestic dogs with jackals, producing a jackal-dog that resembled the
god Anubis.
(Note: Wild horses have 66
chromosomes.
Domestic horses have 64. Wild horses and domestic horses can interbreed and
produce fertile hybrids. The reason golden jackals differ in chromosome number
is most likely because golden jackals have 2 pairs of chromosomes that are twice
as long but contain similar gene content as 4 pairs of dog chromosomes. This
might reduce fertility but it would not likely completely sterilize golden
jackal-dog hybrids.)
In The Variation Of Animals And Plants Under Domestication Charles
Darwin wrote:
- Several years ago I saw confined in the Zoological Gardens of London a
female hybrid from an English dog and jackal, which even in this the first
generation was so sterile that, as I was assured by her keeper, she did not
fully exhibit her proper periods; but this case was certainly exceptional,
as numerous instances have occurred of fertile hybrids from these two
animals.
In Russia, Dog/Jackal
hybrids were bred as sniffer dogs because Jackals have a superior sense of smell
and Huskies are good cold climate dogs. As well as a superior sense of smell,
important at low temperatures where substances are less volatile and therefore
less pungent,
Sulimov Dogs are small sized and can work in confined spaces. When tired,
their normally curled tails droop, making it clear to the handler that the dog
needs to be rested.
The jackal hybrids were bred by senior researcher Klim Sulimov at the
D.S. Likhachev Scientific Research Institute for Cultural Heritage and
Environmental Protection in Russia.
Male Jackal pups had to be fostered on a Husky bitch in order to imprint the
Jackals on dogs. Female Jackals accepted male Huskies more easily. The half-bred
Jackal-Dogs were hard to train and were bred back to Huskies to produce
quarter-bred hybrids (quadroons). These hybrids were small, agile, trainable and
had excellent noses. They are called Sulimov Dogs after their creator and may
one day be registered as a working breed of dog. Twenty-five jackal-dog hybrids
are used by Aeroflot at
Sheremetevo Airport in
Moscow.
References and External Links
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