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Posts Tagged ‘black fox’

bassingbourn black fox

The animal above was an anomalous black fox that was photographed near the village of Bassingbourn in South Cambridgeshire.  The photographer, John Moore, spotted the fox running in the fields near his home and snapped some photos.  It was late March in 2012, and it was a true rare find.

Foxes that are any color other than the typical red are extremely uncommon in the UK, so when these photos were published, speculation about where it came from were rampant. One theory was that it was one of the Belyaev “domesticated” foxes, which were then being sold as pets. Another suggestion was that it was a fur farm escapee. The problem with that theory is that fur farms had been banned in England and Wales since the year 2000, and those last remaining fur farms were mink producers, not fox producers.

Just a few days after John Moore took the photos, the black fox was found dead on the highway. Its body was sent to Anglia Ruskin University for genetic testing to determine why this particular fox was black.

Genetic testing revealed something quite unusual about it.  The vixen was found to have two genetic mutations related to fur color that were similar to those found in raccoon dogs.

Raccoon dogs are very closely related to foxes, and in Russia, they are commonly bred in fur farms that also contain (silver) red foxes and (blue) arctic foxes. Because of the similarity between this fox’s fur color genes and those of a raccoon dog, it was given as evidence that this animal was a Belyaev fox that had been turned loose.

It would make some sense. After all, this vixen was estimated to have been 18 months old, and she was apparently so unwise around roads that she soon met her demise on the highway. Further, her coat was much thicker than a typical English red fox. Maybe someone with more money than sense had ordered up one of these famed “domesticated” foxes, and soon realized they aren’t that awesome to have as pets.

And the poor thing got turned loose to live with the wild English foxes, which is about as a humane thing to do as turning out a cocker spaniel into Alaska to go live with the wolves.

So this logic is easy enough to follow.

The issue that seems to be ignored in all of the discussion about what this fox was is whether it is actually possible for a raccoon dog to hybridize with a red fox.

Ignore what you’ve read in various texts about raccoon dogs. They are actually quite close related to the true foxes. Genome-wide analyses have revealed that they are close enough to the other Vulpini to be classified with them.

They are quite unusual as wild dogs go. They can “hibernate,” which means they just sort of go to sleep during the worst of the winter (but it’s not really “true hibernation.”) They also have masks, and rather superficially resemble actual raccoons. It was not unusual for taxonomists to classify them as a sort of Old World raccoon species. We now know they are actual dogs, but the idea of them being sort of dog-like procyonids certainly captured more than a few imaginations.

So the notion that these animals could hybridize with red foxes would seem far-fetched.

But maybe they have.

The Soviet Union was really interested in fur. Historically, Russia has been a nation of fur-wearers. Furs drove them east and north into new territories, and when fur farms became a possibility, improving fur stains became an important goal. This goal went on in earnest during the Stalin years, and Belyaev, a Mendelian, was driven from his initial research post to accommodate Lysenkoist methodologies. He went to a research facility in Novosibirsk,  where he conducted his experiments on silver foxes.

The Soviet ideology believed that nature could be bent to serve mankind. Socialism in one country meant quite a bit of scarcity, even in the largest country in the world, and it was hoped that the new Soviet science could use native flora and fauna to produce abundance. This abundance would soon provision their citizens, and the Marxist ideal of “from each according to his ability, to each according to his needs” would be possible. Then this ideal would spread to other countries of the world, leading us to a new socialist future and then full-on communism.

It never really worked out, and we all know of the ecological catastrophes that happened as a result of these plans, including the introduction of raccoon dogs to Eastern Europe.

But they made some sense with in the logic of that system.

And if some enterprising Soviet fur farmer wanted to try something different, he might try crossing his silver foxes with raccoon dogs. Maybe he did in the years following the war, when scarcity was the rule, and getting new blood for foxes and raccoon dogs would have been an ordeal.

But this still doesn’t answer the question.

The fact that someone might try crossing the two species is interesting enough, but the question is whether one can produce viable offspring. And the next question whether any of the offspring would be fertile.

I have yet to find the answer to those questions, except that I am aware that red and arctic fox hybrids are sterile.

And those two species are much more closely related to each other than raccoon dogs are to red foxes.

So maybe the black fox of Bassingbourn really wasn’t a hybrid or of distant hybrid ancestry. The similarities in her genotype could have simply been the result of the fact that both red foxes and raccoon dogs share a common ancestor. This fox simply retained a few genes that she held in common with the raccoon dog.

I think that this is a bit better explanation, but the British press took the suggestion that she might have been a hybrid a bit too far. Virtually every mention of this fox online or in print says that she was a hybrid.

I wish, though, that more research had been performed this fox. If she really were the result of a hybridization on a Russian fur farm, it would be possible to detect this hybridization with more analysis of her genome.

The fact that she had just been killed when her body was donated to science meant that lots of different tests could have been performed.

If she really had been derived from hybridization between these two species, this would have been a major discovery.

I don’t think anyone would have expected it.

But Occam’s razor tells me that she wasn’t derived from hybrids.

As much as I’d like her to be, my educated guess is she wasn’t.

And the British press had a lot of fun with it.

 

 

 

 

 

 

 

 

 

 

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Cross fox

Cross fox

Contrary to what you might think of an animal with a name like “cross fox,” this animal is not a hybrid animal. It is a lesser known color phase of the red foxes (Vulpes vulpes). It is called a cross fox because it has a band of dark hair running down its back and another band running accross its shoulders. In the biblical sense, this forms a cross.

As far as I know this color variation appears only in North America. In my region, the most common color phase of this species is the typical red. There are a few cross foxes around, but next to zero melanistic foxes. Melanistic foxes with white hairs mixed are called silvers, but virtually none of these exist in my part of the world, except in captive fur-bearing population.

Now, contrary to popular belief, red foxes cannot hybridize with gray foxes. Reds can breed with silvers, because they are the same species. The gray fox (Urocyon cinereoargenteus) that ranges from southern Canada to Colombia and Venezuela is a very unusual animal.  The genus Urocyon consists of the gray fox and the island fox of the Channel Islands of Southern California. This genus is sometimes considered the most primitive of all dogs, for both of these species retain the ability to climb trees. Indeed, they are very good climbers, almost as good at arboreal locomotion as any cat.

The cross fox is just an interesting coloration of the red fox. It is not a separate species or a hybrid.  Unlike the gray fox, the red fox is not native to most of the Eastern US. Studies of that population confirm that this particular subspecies is almost identical to the red fox of Britain.  This finding makes sense, considering that we have records of introductions from Europe during the eighteenth century.

The Eastern subspecies is Vulpes vulpes fulva. All other subpecies are considered native. The other subspecies tend to  have a higher proportion of melanistic and cross  individuals, both of which are virtually unknown in European populations. It is thought that the melanistic foxes were killed off in Europe, leaving only red ones to breed.  (However, a melanistic one did appear last year in England.)

Now, it’s very interesting that the red fox comes in some many colors. A wide range of coloration matches the varied habitat of this species. Currently, it is the most widespread of all wild carnivores. It is found throughout Eurasia (including Japan), most of North America, and North Africa. It has been introduced to Australia, where it is has proven to be a terrible introduced species, killing off lots of small marsupials and ground nesting birds.

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