Identifying the heritage of a mixed breed dog in the absence of information about its parents or grandparents is difficult, even for knowledgeable dog observers such as veterinarians, because mixed breeds display much more genetic variation than purebreds.
Mixed-breed dogs can be any size, weight, or color; however, some features are more common than others:
- Regardless of parental coloring, the coat color for mixed breed dogs is often a light-to-medium brown (sometimes referred to as "yellow") or black, frequently with white markings on the chest and elsewhere
- A brown coat with black across the top and sides is also quite common especially in outbred dog populations
- Some breeds are more likely than others to pass on their physical traits to mixed-breed progeny
- For example, specific breeds of Collies and Spaniels often produce offspring with their characteristic coat or ear shape
- Crossbred offspring of German Shepherds usually share similar facial shape and features
- Mixed breeds often have an intermediate size between that of their parents
Fading Hereditary Characteristics
With each generation of indiscriminate breeding, the offspring of mixed breed dogs lose the distinguishing traits that are observed in pedigree breeds, and will take on characteristics that are common to many breeds.
For example, wild dogs that have descended from many generations of mixed breed dogs often match the following profile:
- Light brown or black in color
- Weigh approximately 40 lbs
- Stand between 1 and 2 feet tall at the withers
Different Characteristics in Mixed Breed Puppies
Predicting the adult appearance of a mixed breed puppy is difficult; even purebred puppies often do not resemble their adult form.
For example, a single litter from a cross of two pure breeds can produce very different looking puppies as is seen in the example above.