Why can't dogs and foxes interbreed?

Just reading the 'wolfie' thread and someone mentioned that dogs and foxes can't interbreed.

Have to admit that although it now seems obvious I had never thought about it before. Can anyone explain why? They seem to be pretty closely related and dogs and wolves can.

I gave up biology in school, can you tell?

J.

They are not closely enough related to interbreed
although I have heard of some dodgy breeders who have collie pups with a bit of red in them to say there were fox crosses to make a bit more money

I believe that it had to do with the number of Chromosomes Dogs and Wolves have 78 (I think) and foxes 38 approx.

In order for reproduction to take place sperm and egg must contain an equal number of chromosomes

Probably a very simplistic explanation, I also did a quick search about dog cross fox, and there have been claims that this has happened, but unconfirmed.

It is not just the number of Chromosomes, but their ability to match up. Tigers and lions can produce offspring, but many die before birth or produce cubs that cannot reproduce.

Has anyone noticed the silence from scientists on the question of whether humans can mate with apes?

As has been explained, such different species cannot interbreed, their genes are too different to match up and produce anything that could become viable. Where it does happen, i.e. horse/donkey matings (mule) produces a sterile animal as I believe the tiger/lion is also.

The wolf and the dog are, despite being widely cosmetically different, still 99% the same animal genetics wise.

Thanks for all the replies, very interesting.

OT, now I've had time for a little web browsing I have come across an American web site selling (for $5,950! ) those tame foxes bred in Siberia that were on the BBC program 'The secret life of the Dog'. They certainly were very attractive but I wonder if they really are suitable pets?

J.

I remember seeing this on that programme and finding it quite disturbing.

Foxes have "elliptical" eyes too, species that have different pupil shapes cannot interbreed.

Despite what anyone may say, if Foxes could breed with dogs, given the amount of stray dogs and urban Foxes, I think we would have seen a few dont you?

Dogs & Foxes are both members of the Family Canidae, but are of different genus(Dogs~Canis-Foxes~Vulpes). Any males from such a breeding would be sterile as Haldane's Rule applies to such offspring. There have been no genetically proven dog/fox hybrids no matter what anyone claims. The difference in the genetic make up would probably render any embryos inviable in any case.

Me too! But as I watched it I knew that someone, somewhere, would find a way of selling them. Although, having said that it might just be a big con... There were no pictures on the site of the foxes in their new homes with their new owners or even any testimonials.

That's what I'd have thought.

Isn't it interesting that 2 animals that superficially look so similar can actually be so different right down at the chromosomal level. I've learnt something today!

J.