Can Dogs Be Identical Twins?

DNA tests are the only conclusive way to prove identical twin dogs.


Sure, dogs can be fraternal twins – or triplets, or octuplets and so on – but what about identical?

Unlike fraternal twins, which arise from two independently fertilized eggs, identical twins come from the same fertilized egg, which splits and becomes two separate embryos. Depending on when the split occurs, the twins may or may not share a single placenta. The earlier the split, the greater the chance they will each have their own placenta.

Some dog breeders have reported puppies born with only one placenta between them, but even that’s not foolproof. There’s always a chance that two puppies were born one after another and that one placenta became detached and was delivered later. It’s also possible two placentas could grow together and appear to be a single entity.

What about reports of dogs with identical markings? It could be coincidence. But to complicate matters, identical twins would not necessarily share the same markings anyway. That’s because certain characteristics, such as the size and placement of spots, are determined during development by random cell splits that occur after the fertilized egg split.

DNA tests are the only conclusive way to prove identical twin dogs, and no reports exist of dogs proven to be genetically identical. Conjoined animals are often identical twins. Reports of conjoined dogs would be consistent with the idea that they are identical twins because conjoined twins usually result from an incomplete split of a fertilized egg that would have produced identical twins. But although conjoined kittens are not that unusual, conjoined puppies are rarely if ever reported.

So for now at least, there’s no conclusive evidence that identical twins exist in dogs. But who needs science? You already knew that every dog is an individual!


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kelli   warren, Ohio

7/2/2015 9:54:10 PM

I rescued a 6month old bridle pit standing in the middle of a busy intersection. Reported her found and no one claimed her so we adopted her. We took her to get spayed and found out she was already pregnant. 10-14Days away. With 4-5pups. We had 9 we had a pure white one come out with no sac at all and 2pups later another all white with 2sacs.They started having some cream color come out in them. They are identical except in between their shoulder blades . One has a white circle and the other has a cream color circle.

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Ruben   International

2/27/2013 9:09:21 AM

Sherma, since they are male and female proves they are not identical, Identical twins have always same gender

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Sherma   Conyers, Georgia

1/29/2013 5:26:37 AM

I jus wanted to know if dogs can have twins, because my friends mated their pitbulls dogs and 2 of them came out looking like one another, one was a male and the other a female. The male was just a shade darker then his sister, and their are both brendles. So i was jus curious and was trying to get a medical answer..

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suzanne   sunderland, Armed Forces Americas

1/5/2013 11:35:27 AM

I live in uk my Staffordshire bull terrier just 3weeks had 10 pups 1set of twins, 1 pure white and the other pure black. Is that unusal

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