This dog is such a sweetheart — it has been born with a heart-shaped patch on its fur. The little Chihuahua dog has been given the name of Heart-kun after owners discovered the unusual brown marking on its white coat. The puppy was born in Japan and is owned by Emiko Sakurada who breeds dogs to sell to people in her pet shop. Emiko said it was the first time a puppy with the marks had been born out of a thousand she had bred.