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Are there any two breeds of dogs that simply can’t conceive?
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If you cross a chihuahua with a great dane will you get a huge variation in the type of offspring? If the chihuahua was the female would it be possible for the fetus to get to big (and make the mama explode? :P)
i have read that the female will control the size of the foetus to accommodate it naturally within her womb.
i also read about the chihuaha which killed a lion.
the lion choked to death:)
I’m afraid this is only anecdotal, but it may help until an expert comes along.
There’s a vetinary show on TV over here and in an interview, the presenter was asked what was the saddest thing that had happened during the making of it. He told a story about a bitch that had been made pregnant by a much bigger dog (no breeds were mentioned, but the owner had seen it happen). It wasn’t physically possible for her to give birth and by the time the owner had called the vet all the pups had died inside her. They had to do some work to save her life too.
I presume that the size of the litter growing inside a mother dog would be influenced by her ability to supply nourishment to them, and that that would prevent them growing big enough to explode, but it doesn’t seem unlikely that they could do her irreparable damage.
Kid Charlemagne: As long as both dogs are fertile, yes they can conceive. Breed is not equivalent to species (and even some different species can interbreed and create infertile offspring).
For the second question: Given the differences in height, the fetuses will vary in their genetic code for “height”, with some being bigger, others smaller, other intermediates. So yes, there will be variations.
The female uterus has a small influence in size of offspring, mainly because it can only stretch and accomodate litters up to a certain size. Also, a smaller uterus usually means a smaller amount of nutrient exchange which affects the growth of the developing fetus or fetuses.
The problem, as everton says, will be when the animal has to give birth. It not only happens with small dogs, big dogs also have that problem. One of the pups will get stuck in the birth canal and by the time it is taken to the vet, all the pups are dead and mom has an infection.
Well I know THAT. But it is perfectly possible for two breeds of dogs to diverge so much that they are practically different species.
Yeah, but they’d still be dogs, no matter how different the breeds are. An example of different speices would be horses and donkeys. When those two different species are bred, you get an infertile mule.
In Biology that would be what’s called mechanical isolation, that is the two parts just don’t fit correctly. I don’t know what would happen if somehow fertilization occured.
I knew someone whose dog had puppies with neighbour-dog as the poppa.
Afghan-bulldog mix… You know when a creature is so ugly that it’s cute? These puppies weren’t like that.
Their bottom jaws where long and thin, their snouts were much shorter so they all had freaky underbites, the weirdest hair and leg-to-body proportions. Some of the puppies died (they couldn’t suckle properly with their weird jaws – all pups got and human help, but for a few it wasn’t enough). A couple were adopted by people who liked the fact that they looked like radioactive space-alien mutants.
The remaining puppies went to be farm dogs – they developed joint problems and other chronic conditions (gastrointestinal weird stuff etc.), but otherwise are still alive and being the doggiest of dogs.
So, while INAV, I’d say that even the most divergent breeds can have puppies, but there’s probably a point where the offspring may not survive depending on which traits they inherit from their parents.
Preemptive strike: even if two dogs are of such different size that they can’t produce viable offspring, they’d still be considered the same species, because you can get gene flow between all breeds. If a mastiff can’t breed with a chihuahua, it can breed with, say, a collie, which can breed with a beagle, which can breed with the chihuahua. So genetic information isn’t isolated within the breed, and therefore it’s not its own species.
An old housemate of mine had a dog who was a German Shepard- Bassett Hound mix. He was hysterical. He was basically a German Shepard with 4 inch legs who could charge full speed under coffee tables.
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Kid- Well I know THAT. But it is perfectly possible for two breeds of dogs to diverge so much that they are practically different species.
No, it isn’t. They are nowhere near different species. You are thinking about surface differences, not genetic ones.
We used to have a neighbor with a similar dog — apparently a Labrador Retriever - Bassett Hound mix. He had the short stubby legs and the long ears of the basset hound, but the regal head of the lab.
We called him the Bassador.
If a Rottweiter tried to breed with a t-cup poodle, I think that the size of things would make it about impossible for conception.
However, a little dog tends to have smaller litters. . . . even only one puppy. That puppy takes all of the nourishment and becomes very large. A c-section is needed to save mom and kid.
If there are more puppies the puppies are smaller because they share the nourishment.
If it was a very large breed pop and a much smaller mom, the c-section seems about a necessity.