Like us humans, dogs too have multiple distinguishable features that make them truly unique. Merle dog breeds are canines that predominately show the merle coat pattern, a scattering of mottled ...

Another likely culprit is the Australian koolie, a dog with remarkably similar features to the Australian shepherd, such as a merle coat and bright blue eyes.

In the Australian shepherd breed, when a male merle is bred to a female merle, the puppies have a 25 percent chance of being a double merle.

Toy Aussies are also known as “teacup Aussies” and weigh about 15 pounds. They have been bred to be extremely small and though several breeders provide them, they are a relatively new breed.