First documented identical twin dogs delivered

Twin puppies Romulus and Cullen play together. Photo courtesy of Rant en Dal Animal Hospital.Kurt de Cramer, BVSc, MMedVet (Gyn.), of Rant en Dal Animal Hospital in Mogale City, South Africa, noticed distress and prolonged abdominal straining during a Cesarean section on a female Irish wolfhound when she was due to give birth. He also noticed an unusual bulging by her uterus, according to a report from the BBC. 

Though there were five live puppies, each with their own placenta arranged single-file within the uterus, de Cramer noticed that there were two others attached to one placenta. “When I realized 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 in the BBC report.

According to the report, after calling upon other reproductive specialists, de Cramer and the team he had assembled obtained blood samples from the twins once they reached 2 weeks of age in order to genetically confirm what de Cramer suspected. The results showed that the puppies were genetically identical. 

"There have been rumors about twin dogs before," says Carolynne Joone, lecturer on veterinary reproduction at James Cook University in Townsville, Australia. “We just happened to be lucky enough to confirm it genetically.” 

Even though this is the first confirmed instance of genetically identical canine twins, it is impossible to tell just how rare the occurrence is. “It has taken so long for us to find a monozygotic pair, so they are probably rare,” Joone says. “But so many of them will have been born naturally and blissfully unaware.”

But for identical twin pups to be delivered naturally is dangerous. “It is even less likely for placenta-sharing puppies to survive,” de Cramer says in the BBC report, “because of several complications relating to nutrient and oxygen supply from a single placenta having to do the job that is normally done by two placentas.”

Though they were slightly smaller at birth, the twin puppies, Cullen and Romulus, are still doing well.

You can read more on the study and research of this case here.