“When I realised that the puppies were of the same gender and that they had very similar markings, I also immediately suspected that they might be identical twins having originated from the splitting of an embryo,” says de Cramer.
“The twins looked very similar,” says Dr Joone Carolynne of James Cook University in Townsville, Australia . “But pups from the same litter often do, [and] there were small differences in the white markings on their paws, chests and the tips of their tails. I wasn’t sure they were monozygotic [identical] at all initially.”
“Yes, there would have been one less placenta than there were pups, but as the bitch often eats the placentas the owner probably would have simply shrugged this off. There have been rumours about twins in dogs before,” says Joone. “We just happened to be lucky enough to be able to confirm it genetically. It has taken so long for us to find a monozygotic pair, so they are probably rare,” says Joone. “But so many of them will have been born naturally and blissfully unaware.”