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Posts Tagged ‘raccoon dog’

I would hope they would have used red dachshunds to avoid accidentally shooting the dog when it comes out of the hole:

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Raccoon dogs are an invasive species in Europe.  These golden retrievers take care of business.

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This black fox was shot at Bassingbourn in Hertfordshire, England.  It was photographed just before it was killed by a car:

It was assumed that this animal had been a fur farm escapee, for melanistic foxes are quite uncommon in the British Isles.

A DNA test was performed.

It was revealed to be an 18-month-old red fox, but its gene for pigmentation was not the same as the typical black or silver fox gene.

Its gene for pigmentation was nearly an exact match for a raccoon dog.

Most of the media attention was focused on how this animal could have been one of the Belyaev tame foxes, but that’s not what’s most interesting.

If it had been one of Belyaev’s tame foxes, then it would make sense that a tame one could have been brought into England as a pet. However, these foxes would be subject to quarantine, and there would be a record of their import. Further, all of those tame foxes that have been sold as pets arrive neutered.

This fox was a male, so it would have been mentioned if it had been neutered.

However, what’s much more interesting is the potential source for the pigmentation gene.

In profile, this fox looks really weird. It has really shaggy fur, and it has a pronounced stop.

Could it have had some raccoon dog ancestry?

Both raccoon dogs and red foxes have been bred on fur farms for decades.

Recent genetic research has revealed that raccoon dogs are actually foxes, but they are quite distantly related to red foxes, last sharing a common ancestor somewhere around 4-5 million years ago.

They are at the edge of when two species start to the ability hybridize.

However, if this gene were introduced into farmed red foxes through crossbreeding with raccoon dogs, it actually does make sense. (If it were possible.)

For decades, the Soviet Union was cut off from the West, and the main source for silver foxes was North America. Almost all silver foxes in captivity today can trace to wild population in the Canadian Maritimes.

Because the Russians were cut off, they likely were trying to do lots of things to improve their fur stock. Part of what Belyaev was trying to do was improve the fur farmed stock.

Could the Soviets have been crossing raccoon dogs with silver foxes in order to increase pelt quality and the black color?

Both male and female red fox and arctic fox hybrids– which are closer relatives than red foxes and raccoon dogs–are sterile, so if this animal is a hybrid between these two species, we have lots of questions that need to be answered.

If we occasionally get fertile raccoon dog/silver fox hybrids, then why are arctic fox and silver fox hybrids sterile?

I would be surprised if this animal had been a first cross between a raccoon dog and a red fox. If it had been, it would have had more raccoon dog ancestry than just this gene.

More genetic studies need to be performed on this fox.

We may have found nothing more than a really novel genetic mutation for melanism in the red fox than we have not seen before.

But the hypothesis that this gene could have entered the farmed red fox population through cross-breeding needs to be explored.

This unusual fox is really strange.

The DNA evidence just makes things even more intriguing.

***

Update (5/31/12) I’ve been unable to find any confirmation of the raccoon dog gene in any other source.

Therefore, I’m going to say that it’s most likely not a hybrid.

It’s just a fox with a similar mutation to those that exist in raccoon dogs.

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The Japanese raccoon dog should be considered a distinct species from those on the mainland. It has a very different chromosome number.

The raccoon dog (Nyctereutes procyonoides) is a native of Asia.  The Soviet Union introduced raccoon dogs from the Russian Far East into several of its European and Caucasian Republics, and it is now well established in parts of Europe.

However, the exact taxonomy of raccoon dogs is quite fiercely debated.

There is some debate as to whether it should be classified as a basal canid that doesn’t belong to the Canini tribe (all true dogs and South American wild dogs) or the Vulpini tribe (all the true foxes) or whether it is actually a very primitive vulpine. I lean toward classifying it as a primitive vulpine, a classification it shares with the bat-eared fox (Otocyon megalotis).  The gray and island foxes (genus Urocyon) are true basal canids and belong to neither tribe, but the classification of these three species varies quite a bit in the literature.

But even more hotly contested than its position in the dog family’s phylogenetic tree is how many species of raccoon dog actually exist.

As regular readers of this blog know, I’m very skeptical of splitting species. For example, I have real issues with the current classification of the island fox, which lives on the Channel Islands of California, as a distinct species from the mainland gray fox. It has the same chromosome number as the mainland gray fox (2n=66). They are likely still interfertile, and their introduction to the islands may have occurred only through human agency.  Native Americans may have brought pet gray foxes to the islands, where they lived in semi-wild existence. Over time, they evolved into a slightly different kind of gray fox, which is smaller and somewhat tamer than those found on the mainland.

However, the Japanese subspecies of the raccoon dog (N. p. viverrinus) has a much different situation from its mainland relatives than the island fox has from the gray fox.

For example, the Japanese raccoon dog has much fewer chromosomes than the two mainland subspecies.  The mainland subspecies has 2n = 54, while the Japanese raccoon dog’s 2n=38.

That’s not a trivial chromosome difference.

Now, the ancestral raccoon dog colonized Japan just a little bit earlier than the island fox colonized its islands, but evolution has worked very differently in the case of the Japanese raccoon dog. No one has provided me any conclusive data that island foxes should be considered a distinct species, but this very wide chromosome number difference between Japanese and mainland raccoon dogs really sticks out.

Why on earth would anyone be so cavalier about calling island foxes a species and totally poo-poo the notion that Japanese raccoon dogs are?

That’s the decision of the International Union for Conservation of Nature Canid Group’s Canid Biology and Conservation Conference in 2001. This same group readily accepts the island fox as a species, but the Japanese raccoon dog has to be a subspecies.

Now, it’s likely that different panels of scientists are coming up with these decisions, but the cognitive dissonance between the decision to recognize the island fox as a unique species and deny the raccoon dog is more than a little bit troubling. Nie (2003) performed a chromosome map analysis on a Chinese raccoon dog, a Japanese raccoon dog, and a domestic dog and found that the Japanese raccoon dog really was quite distinct from the Chinese specimen.

Thus, the Japanese raccoon dog should be considered a distinct species (Nyctereutes viverrinus).

And it already has a fine common name to distinguish it from the mainland species. The Japanse call it the tanuki.

The evidence for this animal being a unique species is much stronger than exists for all the proposed new species of wolf that have been bandied about over the years. The Eastern wolf and red wolf of North America are actually wolf and coyote hybrids, and the genome-wide analyses have failed to find the uniqueness of Indian and Himalayan wolves, which were also proposed to be separate species based upon their ancient mtDNA lineages.

The tanuki shows that speciation can happen rapidly, especially when we’re talking about isolated island populations.  But just because an animal is stuck on an island for a couple of thousand of years doesn’t mean that it will evolve into a new species. The mutations and chromosome fusions that happened with the Japanese raccoon dog didn’t happen with the island fox.

But because they did happen with the tanuki, we ought to be more open to considering it a unique species.

The only thing that will settle this argument is if an in depth genetic analysis is performed, as was the case with the clouded leopard. There are now two species of clouded leopard, but until one of these analyses was performed, the exact taxonomy of the raccoon dog will be fiercely debated.  It is unlikely that the mainland and Japanese raccoon dogs are as genetically distinct as the mainland and Sunda clouded leopards, but having such extreme differences in chromosome number might mean that they are no longer chemically interfertile.

And if they aren’t, why on earth would we call them the same species?

Genome-wide analyses might even show that these two species split much earlier than is normally posited. The raccoon dog is considered  one of the most ancient extant evolutionary lineages in the dog family. It is possible that there were once many species of raccoon dog, and it might be that the Japanese raccoon dog, instead of evolving from the mainland species, is actually relic population of a species that has since gone extinct on the mainland.  The raccoon dog lineage may have included jackal-like animals, for specimens of a so-called primitive jackal that lived during the Middle Pleistocene in Northwest Africa were found to have skulls and dentition that resemble those of a raccoon dog.  Instead of being an ancestor of any living jackal species, perhaps this animal is actually a type of raccoon dog that evolved into something like a jackal.

Raccoon dogs are much more complex animals than we might realize. They may not be as charismatic as wolves are, but their evolutionary history and taxonomy have many questions that have yet to be answered.

But the bulk of the evidence suggests that at least two species of raccoon dog exist.

It’s just tough to change this paradigm.

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Raccoon dog puppy

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Despite the comments on this video, there are no raccoons in Finland.

This animal was introduced as a fur-bearer to the former Soviet Union (Latvia, which is now an independent country on the Baltic). It is native to Asia, not Europe.

However, there are raccoons in Central and Western Europe. They were introduced by the Nazis to Germany. The Soviets also turned out raccoons in the Caucasus and in Byelorussia/Belarus. Neither of those populations is found in Western Europe.

So blame the Soviets for the raccoon dog.

And blame the Nazis for the raccoons.

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raccoon-dogs1

Raccoon dogs are strange dogs. When I say raccoon dogs, I’m not talking about coonhounds. I’m not talking about “Ol’ Blue.”

I am talking about an unsual canid that was originally found only in Asia, but  the Soviets introduced them to Latvia after World War II. Their range expaneded rapidly to encompass a wide range of Europe.

This species is one of those primitive dogs, like the gray fox. And like the gray fox, the raccoon dog can climb trees. However,  it is not as good at it as the gray fox is.

These dogs go into a kind of hibernation during the coldest months of the winter. They go torpid during this time period, just like the true raccoon.

In parts of Europe, especially Germany, both introduced raccoons and introduced raccoon dogs live in the same forests. But they are not that closely related.

If you would like to see one bayed by a Finnish hound, check out the video below:

These animals are a bit of pest in parts of their range. They kill lots of small animals and destroy ground bird’s nests.

Raccoon dogs can be kept as pets in some European countries. However, these are fundamentally wild animals, and they don’t have all the nice traits that make domestic animals so easily to deal with.

The raccoon dog is a strange animal. We don’t have them in North America, so when people see pictures of them, they think they are large raccoons. Or if they hear the term “raccoon dog,” they think of Where the Red Fern Grows. It’s really just another species of wild dog, albeit a rather strange one.

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