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Author Topic: Can dogs breed with foxes?  (Read 27882 times)

stevewillie

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Can dogs breed with foxes?
« on: 16/09/2008 05:30:05 »
I've always understood that the definition of a species is that its members can interbreed, but cannot breed with other species. In the case of canines, wolves ('canis lupus') and domestic dogs ('canis domesticus') can interbreed. Apparently some domestic dog breeds can, or used to able, to breed with foxes (vulpes fulve) which are a different genus. Does this mean that biological taxonomies are not as sharply defined as many believe? 
« Last Edit: 19/09/2008 21:38:41 by chris »

atrox

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Re: Can dogs breed with foxes?
« Reply #1 on: 16/09/2008 10:38:26 »
Species are not only defined by if its possible for them to interbreed in general, but also how likely it is to interbreed under normal/natural conditions. Some species would maybe interbreed, if there where no topographical borders. SOme species could interbreed if their behaviour wouldnt prevent it.
Lions and tigers are different species, horses and donkeys too... but its possible for them, to beget mules, liger oder tigons and so on.
Mostly these breeds are not fertile. And mostly these animals wouldnīt result without captivity and no possibility to get a partner of the own species..

But by the way, there are still discussions about the concept of a species...

Don_1

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Re: Can dogs breed with foxes?
« Reply #2 on: 16/09/2008 14:36:57 »
Wow! This could explain why our daughter is having trouble getting preggers. I'm am now convinced my Mrs is not of the species Homo Sapien.


If she see's this, I'm dead.

stevewillie

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Re: Can dogs breed with foxes?
« Reply #3 on: 16/09/2008 18:56:01 »
Species are not only defined by if its possible for them to interbreed in general, but also how likely it is to interbreed under normal/natural conditions. Some species would maybe interbreed, if there where no topographical borders. SOme species could interbreed if their behaviour wouldnt prevent it.
Lions and tigers are different species, horses and donkeys too... but its possible for them, to beget mules, liger oder tigons and so on.
Mostly these breeds are not fertile. And mostly these animals wouldnīt result without captivity and no possibility to get a partner of the own species..

But by the way, there are still discussions about the concept of a species...


Atrox

I'm wondering if the huge variety in the size and shapes of domestic dogs
isn't leading to new species. It's hard to see a Great Dane mating with a chihuahua under natural conditions.

DoctorBeaver

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Re: Can dogs breed with foxes?
« Reply #4 on: 17/09/2008 08:43:57 »
Species are not only defined by if its possible for them to interbreed in general, but also how likely it is to interbreed under normal/natural conditions. Some species would maybe interbreed, if there where no topographical borders. SOme species could interbreed if their behaviour wouldnt prevent it.
Lions and tigers are different species, horses and donkeys too... but its possible for them, to beget mules, liger oder tigons and so on.
Mostly these breeds are not fertile. And mostly these animals wouldnīt result without captivity and no possibility to get a partner of the own species..

But by the way, there are still discussions about the concept of a species...


Atrox

I'm wondering if the huge variety in the size and shapes of domestic dogs
isn't leading to new species. It's hard to see a Great Dane mating with a chihuahua under natural conditions.

I've come across an instance of a Doberman that was serviced by a Dachshund. Presumably there was a convenient step-ladder.

atrox

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Re: Can dogs breed with foxes?
« Reply #5 on: 17/09/2008 10:34:09 »
Hi Stevewilli!

Your wonders are justified. As I said, the concept of species is still discussed, also there are two main concepts.
The first is the typological concept, in which they devide species by morphology, means by appaerance. You can clearly tell, that a lion and a tiger are different species by just looking at them.
The second way is the biological concept. That means, that every natural population which is able to breed potenntially
porpagable offspring is a species. As I said a tiger and a lion could breed under artificial conditions, but there is absoltely no sign, that they would interbreed in nature.
(Liger)


But both concepts have problems. It could be a problem to tell, that all the different castes of ants are one species. Also every differnt kind of dog would be a differnt species... so a Shepard and a Doberman would be different species although they are easily able to reproduce. I think that concept worked a while ago more or less, but today its just archaic..
The concept with the so called biospecies lags too. There are problems in definition of asexual species the problem with the "race circles" I mentioned a few times in other threads.
If you go all the way of the "race circle" from the beginnig to the end, it would clearly be one species, because they all interbreed. But if the beginning and the end of the circle meets, they would not reproduce, so they would clearly be no species...


In my opinion, a Doberman and a Shepard are only different races of one species, but a Mastiff and a Chihuahua would be different Species, because they are not very likely to interbreed... but where schould you draw the line then? Thats not that easy ;-)

(By the way, I know a few Dachshund-Shepard-Crossbreeds..they are not that rare)

blakestyger

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Re: Can dogs breed with foxes?
« Reply #6 on: 17/09/2008 19:20:03 »
Atrox - all dogs are varieties of the same species. It is likely that any one variety is able to breed with any other. The only thing that may stop them is human intervention - the same intervention that was responsible for all the varieties in the first place; not to mention the difficulty a really small type of dog would have in bringing to term a litter from a really large type.
Remember, all dogs are artifacts and although they are originally from wolves they do have some wolfy behaviour but they mostly differ - wolves don't bark and don't take kindly to being left alone in the house.
It would be interesting to see if anyone has recorded a wolf/dog hybrid; I think it's likely but a dog/hyena hybrid would be impossible as they are taxonomically closer to cats.

stevewillie

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Re: Can dogs breed with foxes?
« Reply #7 on: 17/09/2008 21:22:26 »
Hi Stevewilli!

Your wonders are justified. As I said, the concept of species is still discussed, also there are two main concepts.
The first is the typological concept, in which they devide species by morphology, means by appaerance. You can clearly tell, that a lion and a tiger are different species by just looking at them.
The second way is the biological concept. That means, that every natural population which is able to breed potenntially
porpagable offspring is a species. As I said a tiger and a lion could breed under artificial conditions, but there is absoltely no sign, that they would interbreed in nature.
(Liger)


But both concepts have problems. It could be a problem to tell, that all the different castes of ants are one species. Also every differnt kind of dog would be a differnt species... so a Shepard and a Doberman would be different species although they are easily able to reproduce. I think that concept worked a while ago more or less, but today its just archaic..
The concept with the so called biospecies lags too. There are problems in definition of asexual species the problem with the "race circles" I mentioned a few times in other threads.
If you go all the way of the "race circle" from the beginnig to the end, it would clearly be one species, because they all interbreed. But if the beginning and the end of the circle meets, they would not reproduce, so they would clearly be no species...


In my opinion, a Doberman and a Shepard are only different races of one species, but a Mastiff and a Chihuahua would be different Species, because they are not very likely to interbreed... but where schould you draw the line then? Thats not that easy ;-)

(By the way, I know a few Dachshund-Shepard-Crossbreeds..they are not that rare)
Atrox - all dogs are varieties of the same species. It is likely that any one variety is able to breed with any other. The only thing that may stop them is human intervention - the same intervention that was responsible for all the varieties in the first place; not to mention the difficulty a really small type of dog would have in bringing to term a litter from a really large type.
Remember, all dogs are artifacts and although they are originally from wolves they do have some wolfy behaviour but they mostly differ - wolves don't bark and don't take kindly to being left alone in the house.
It would be interesting to see if anyone has recorded a wolf/dog hybrid; I think it's likely but a dog/hyena hybrid would be impossible as they are taxonomically closer to cats.

Thanks atrox. You seem to have a good knowledge of this topic. I also agree with you blakestyger that domestic dogs are one species. If nothing else, it's based on the existing taxonomy and all dogs can interbreed. However, we may have passed the point where the largest dogs and smallest can interbreed safely. To cross a chihuahua with a St Bernard would probably require in vitro fertilzation and definitly require implantation in the large dog. If humans do not maintain this possibility, in time it seems that the large dogs and small dogs will be, at the very least, distinct species if not distinct genus. I think this is equivalent geographic isolation, which rapidly (in evolutionary terms) leads to new species.     
« Last Edit: 17/09/2008 21:25:20 by stevewillie »

atrox

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Re: Can dogs breed with foxes?
« Reply #8 on: 17/09/2008 22:59:10 »
It would be interesting to see if anyone has recorded a wolf/dog hybrid;

In fact, there are a lot of them. Mostly in eastern european countries, but meanwhile, there are a lot in Germany too.
Some guesses say, that there are 10.000 to 20.000 wolve-dog-hybrids in Germany...mostly illegal, because you need a special license to keep such an hybrid because the european wolve is in the CITES lists.
They started to mix wolves an dogs about 20 years ago, because they hoped to get healthier dogs. But in fact they get wolve-dogs which are almost allways pretty wolvish in their behaviour... even the later wolveblooded generations are not apropriate to live with humans. They are (or get in an age about 2 or 3 years)mostly pretty aggressive and unpredictable.
But wolve-dog-interbreeds in nature are more or less pretty seldom. In most cases its not very... healthy for a dog to meet a wolve ;-). But in some cases, mostly if a wolve immigrate to regions, where are no or not many other wolves ( a lack of partners of the same kind) natural dog-wolve hybrids could result..

Of course a dog is a dog is a dog...no matter what it looks like. We know, that they all originate from wolves. But in the case of a mastiff and a chihuahua for example, no concept of species really fits. Of course its possible for them to interbreed in rare cases...but really not very likely... and so the concept of biospecies doesnīt really fit. Neither does the morphological concept of course.
There are also genetic concepts nowadays.. of course then they would fit...but these concepts have their own problems, so that they are not universal as well..

I just wonder, if I would be an alien biologist from another planet and I would land on earth to see all the things like they are today...would I really think a Chihuahua and a Mastiff would be one species...?

In fact, dogs are like an artificial "race circle"... you can go from one end to the other end, and every dog would interbreed with the next one...but reproduction between the end and the beginning of the circle wpuld be pretty unlikely..

DoctorBeaver

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Re: Can dogs breed with foxes?
« Reply #9 on: 18/09/2008 07:16:54 »
During Apartheid a few South African farmers crossed Boerbels (South African Mastiffs) with Timber Wolves. They were used as guard dogs to keep the blacks off their land when they weren't working. Not very nice.

atrox

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Re: Can dogs breed with foxes?
« Reply #10 on: 18/09/2008 08:58:51 »
oh...and when I said "Mostly in eastern european countries" itīs just because, I just had an eye on Europe ;)
I know that there are a lot of wolve-hybrids in arctic countries too... Malamute-wolve-hybrids are pretty common..

stevewillie

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Re: Can dogs breed with foxes?
« Reply #11 on: 19/09/2008 20:44:47 »
I just wonder, if I would be an alien biologist from another planet and I would land on earth to see all the things like they are today...would I really think a Chihuahua and a Mastiff would be one species...?

Atrox

If the ETs come they better come soon. Assuming we continue to make progress, the mastiff-chihuahua issue will be trivial. Humans have been involved in intentionally engineering evolution since neolithic times by selective hybridization. Now with modern genetic engineering making technologically exponential progress, we are literally on the threshold of a new paradigm of evolution. Given another 100 years (ignoring the obvious existential threat if we get it wrong) there will be species we can't imagine today and that doesn't include bionic "species"(part living, part machine.)

Ray Kurzweil wrote an important book on this (The Singularity Is Near, Viking, 2005.) I also wrote a book which deals with this issue from a different perspective (see biography).       
« Last Edit: 19/09/2008 20:49:23 by stevewillie »

Andrew K Fletcher

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Can dogs breed with foxes?
« Reply #12 on: 20/09/2008 09:07:49 »
I have heard of a bull dog crossed with a shitzu, producing a bullshit

Question:

My Bull terrier bitch is called Ruby Loved dearly and loves everyone. Now it's got me thinking. If I crossed her with a poodle and then crossed her prodgeny with a dandy dinmont would I get a Ruby Doodle Dandy?
« Last Edit: 20/09/2008 09:10:57 by Andrew K Fletcher »

catplay

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Re: Can dogs breed with foxes?
« Reply #13 on: 11/05/2013 12:42:03 »
Hi Stevewilli!

Your wonders are justified. As I said, the concept of species is still discussed, also there are two main concepts.
The first is the typological concept, in which they devide species by morphology, means by appaerance. You can clearly tell, that a lion and a tiger are different species by just looking at them.
The second way is the biological concept. That means, that every natural population which is able to breed potenntially
porpagable offspring is a species. As I said a tiger and a lion could breed under artificial conditions, but there is absoltely no sign, that they would interbreed in nature.
(Liger)


But both concepts have problems. It could be a problem to tell, that all the different castes of ants are one species. Also every differnt kind of dog would be a differnt species... so a Shepard and a Doberman would be different species although they are easily able to reproduce. I think that concept worked a while ago more or less, but today its just archaic..
The concept with the so called biospecies lags too. There are problems in definition of asexual species the problem with the "race circles" I mentioned a few times in other threads.
If you go all the way of the "race circle" from the beginnig to the end, it would clearly be one species, because they all interbreed. But if the beginning and the end of the circle meets, they would not reproduce, so they would clearly be no species...


In my opinion, a Doberman and a Shepard are only different races of one species, but a Mastiff and a Chihuahua would be different Species, because they are not very likely to interbreed... but where schould you draw the line then? Thats not that easy ;-)

(By the way, I know a few Dachshund-Shepard-Crossbreeds..they are not that rare)

It's called phenotype, for physical appearance (you stated it's called a, "typological concept") and genotype for the actual genetic make up of a species (you stated it's called a, "biological concept").  You sort of got the concepts correct, but not fully, and the terminology you used was not spot on.  Just wanted to clarify

CliffordK

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Re: Can dogs breed with foxes?
« Reply #14 on: 11/05/2013 16:18:22 »
According to Wikipedia:

Members of the dog genus Canis: wolves, dogs (both common dogs and dingoes), Ethiopian Wolves,[1] coyotes, and golden jackals cannot interbreed with members of the wider dog family: the Canidae, such as South American canids, foxes, African wild dogs, bat-eared foxes or raccoon dogs; or, if they could, their offspring would be infertile.

Just looking at chromosomes, Dogs, Wolves, & Coyotes have 39 pairs, or 78 total chromosomes.
The red fox has 34 chromosomes (17 pairs) and from 0 to 8 small B chromosomes.
The grey fox has 66 chromosomes (33 pairs).
The fennec fox has 64 chromosomes (32 pairs).
The Bengal Fox has 60 chromosomes (30 pairs).
The kit fox has 50 chromosomes (25 pairs).
The Tibetan sand fox has 36 chromosomes (18 pairs).
The Bat-eared Fox has 72 chromosomes (36 pairs)
The the raccoon dog has 42 chromosomes (21 pairs).

Some animals with different chromosome numbers can breed once if they are similar enough, but generally the offspring are infertile. 
For example, Horses (64 chromosomes), Donkey (62 chromosomes), and zebras have 32 to 46 chromosomes.  They can interbreed, but their offspring are always sterile due to inheriting an odd number of chromosomes.

Apparently no verifiable dog/fox hybrids have occurred. 

Martin J Sallberg

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Re: Can dogs breed with foxes?
« Reply #15 on: 14/05/2013 06:31:32 »
All gene-centered theories of reproductive barriers have serious flaws. If the barrier is supposed to come into place by gradual accumulation of differences, then it should be possible to predict reproductive barriers based on genetic difference data alone. It is not. Experiments with irradiated fruit flies shows that some became sterile directly while others remained fertile up to 20% mutated DNA. Lizards from different islands in the Martinique island chain interbreed and produce fertile offspring... and genetically they are almost as different as a human from a chimp.

The gradual accumulation theory also predicts that big populations with little genetic drift should accumulate individual variation until they became sterile and died out, and yet there is not one scrap of empirical evidence for large populations spontaneously becoming sterile and dying out.

The theory of single key mutations, on the other hand, has the problem of how the first individual with the key mutation should find a mate.

So all theories of genes determining reproductive species barriers are fatally flawed. Maybe mutations are not random...

wolfekeeper

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Re: Can dogs breed with foxes?
« Reply #16 on: 14/05/2013 22:17:40 »
I have no idea what you're talking about Martin; nobody claims that a simple count or percentages of mutations determines species, nor that a single mutation can cause speciation. And I cannot begin to even imagine how a species with a large number of individuals can have zero genetic drift; the bigger the number of members the more variation you get.

Mutations that survive are definitely not random anyway, the DNA has to interact with the other DNA around it to produce a working individual that can reproduce with other individuals.

Tellingly there's known examples of 'ring species', where an individual at one end of a country is unable to breed with an individual from the other end, but all the intervening individuals can breed. To cause a speciation event, removing the middle individuals can promptly cause the two ends to become different species.

The idea that you cannot get speciation from genetic modification is just rubbish.
« Last Edit: 14/05/2013 22:19:15 by wolfekeeper »

CliffordK

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Re: Can dogs breed with foxes?
« Reply #17 on: 15/05/2013 03:59:47 »
There are many humans that are sterile for one reason or another.  Often poor sperm sperm motility, or damage to the fallopian tubes.  And, of course, some genetic diseases that are lethal before adulthood (not to mention the miscarriages).  Anyway, so not every member of the species breeds.

When comparing human to chimp chromosomes, there is a 2A/2B fusion in humans that never occurred in the Apes. 
http://genetics.thetech.org/ask/ask69


H: Human
C: Chimp


What happened to the first hominid that had the 2A/2B fusion? 

Here is an interesting note about chromosome fusions.  The idea is that originally the chromosome fusion may be somewhat like a chromosome translocation. which naturally occurs in a portion of the population.  It is possible that after the fusion, not all the offspring were viable.  But, as the single fused chromosome spread throughout the population, those individuals who managed to inherit either 2 fused chromosomes and mated with other individuals with 2 fused chromosomes undoubtedly fared better than those who were heterozygous. 

If the two groups of individuals underwent some kind of isolation event, or perhaps a bottleneck event, then additional mutations might have accumulated until they were no longer compatible.  Perhaps those individuals who eventually inherited the homozygous mutation were qualitatively different than those who were either heterozygous, or without the fusion, and those individuals were able to recognize better mate compatibility.

Chromosome fusion and fission events seem to occur in all species, and after the genome stabilizes they seem to be defining characteristics of that species.

Interbreeding within a family or small tribe would facilitate the spreading of a new chromosome mutation, and the development of homozygous individuals.

One may note that every surviving human race has undergone some kind of isolation in the past, causing distinctive hair, skin, and complexion differences, but all are able to interbreed.

Martin J Sallberg

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Re: Can dogs breed with foxes?
« Reply #18 on: 15/05/2013 05:45:26 »
I have no idea what you're talking about Martin; nobody claims that a simple count or percentages of mutations determines species, nor that a single mutation can cause speciation.

So nobody believes in gene-gradualistic speciation, and nobody believes in gene-sudden speciation either. You just said that nobody believes in either of the two versions of gene-centered speciation theory.

And I cannot begin to even imagine how a species with a large number of individuals can have zero genetic drift; the bigger the number of members the more variation you get.

With "genetic drift" I meant random elimination of alleles, not an increase in diversity. The greater variation of larger populations was exactly the argument I used to show that gene-centered speciation theory predicts that large populations should accumulate too much genetic variation to be fertile, and spontaneously die out.

Mutations that survive are definitely not random anyway, the DNA has to interact with the other DNA around it to produce a working individual that can reproduce with other individuals.

Not sufficient. I meant that there must be synchronization that makes the same mutation happen in multiple individuals at once, if genes matters.

Tellingly there's known examples of 'ring species', where an individual at one end of a country is unable to breed with an individual from the other end, but all the intervening individuals can breed. To cause a speciation event, removing the middle individuals can promptly cause the two ends to become different species.

The idea that you cannot get speciation from genetic modification is just rubbish.

Ever heard of "correlation does not equal causation"? It may be some other factor that prevents interbreeding, maybe the placebo effect.

Martin J Sallberg

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Re: Can dogs breed with foxes?
« Reply #19 on: 15/05/2013 05:52:21 »
If the two groups of individuals underwent some kind of isolation event, or perhaps a bottleneck event, then additional mutations might have accumulated until they were no longer compatible.

That gradual theory predicts those false things that large populations should spontaneously become sterile and die out, and that there should be a fixed relationship between genetic difference and degree of reproductive barrier.


Perhaps those individuals who eventually inherited the homozygous mutation were qualitatively different than those who were either heterozygous, or without the fusion, and those individuals were able to recognize better mate compatibility.

Which is incompatible with the neo-Darwinian belief that most DNA must be junk or else there would be too many fatal mutations.

Chromosome fusion and fission events seem to occur in all species, and after the genome stabilizes they seem to be defining characteristics of that species.

One mutation or many mutations, the problems remains, just in different but equally fatal forms.

wolfekeeper

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Re: Can dogs breed with foxes?
« Reply #20 on: 15/05/2013 12:38:59 »
Tellingly there's known examples of 'ring species', where an individual at one end of a country is unable to breed with an individual from the other end, but all the intervening individuals can breed. To cause a speciation event, removing the middle individuals can promptly cause the two ends to become different species.

The idea that you cannot get speciation from genetic modification is just rubbish.

Ever heard of "correlation does not equal causation"? It may be some other factor that prevents interbreeding, maybe the placebo effect.
Ah, I see you are a fan of the Chewbacca defence.

I can only assume you are a creationist, because nobody else would be claiming that speciation isn't genetic!!!

I don't think we're here to discuss creationism, we're here to do science. Either explain why ring species aren't at least one mechanism for speciation, or leave the board. Thanks!
« Last Edit: 15/05/2013 12:40:45 by wolfekeeper »

Martin J Sallberg

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Re: Can dogs breed with foxes?
« Reply #21 on: 15/05/2013 15:33:27 »
Tellingly there's known examples of 'ring species', where an individual at one end of a country is unable to breed with an individual from the other end, but all the intervening individuals can breed. To cause a speciation event, removing the middle individuals can promptly cause the two ends to become different species.

The idea that you cannot get speciation from genetic modification is just rubbish.

Ever heard of "correlation does not equal causation"? It may be some other factor that prevents interbreeding, maybe the placebo effect.
Ah, I see you are a fan of the Chewbacca defence.

I can only assume you are a creationist, because nobody else would be claiming that speciation isn't genetic!!!

I don't think we're here to discuss creationism, we're here to do science. Either explain why ring species aren't at least one mechanism for speciation, or leave the board. Thanks!

Nonsensical association fallacy. I am not a creationist. I reject the "intelligent design" movement too. In fact, I do not believe in any set of "true" species at all, in stark contrast to the "species immutability" belief of creationists. I think all "species barriers" are fundamentally non-genetic, without exception. What I argue for is that genes are not a fixed determinator at all, but instead edited by function-sensitivity. It is the neo-Darwinist debate rhetoric of assuming that anyone criticizing neo-Darwinism should be a creationist that should not be taken seriously.

wolfekeeper

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Re: Can dogs breed with foxes?
« Reply #22 on: 15/05/2013 15:42:47 »
This isn't the forum for new theories, if you don't stop posting new theories here, I will contact the administrators and get you blocked. Thanks!

 

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