Blood tests would later back up de Cramer's suspicions - the puppies had identical DNA profiles. "Monozygotic twinning has not previously been genetically confirmed in the dog," researchers wrote in a study on the findings.
While these puppies are the first confirmed case of identical twin dogs, there's a chance others are out there. Truth is, without seeing puppies in utero or comparing their DNA later on, it would be difficult to determine if two pups were actually monozygotic twins.
"It has taken so long for us to find a monozygotic pair, so they are probably rare," researcher Carolynne Joone said. "But so many of them will have been born naturally and blissfully unaware."
And it's hard to beat the bliss of puppies, identical or not.