Mixed-breed dog, todays featured article

A mixed-breed dog (also called a mutt, crossbreed, mongrel, a bitsa, tyke, cur, or random-bred dog) is a dog that has characteristics of more than two breeds, or is a descendant of feral or pariah dog populations. The term "mutt" generally refers to a dog of unknown descent. Dogs interbreed freely, except where extreme variations in size exist, so mixed-breed dogs vary in size, shape, and color, making them hard to classify physically. Historically, all purebred dogs have been selectively bred from a mixed-breed population.

All possible body shapes, ear types, and tail styles can appear in mixed breeds. Extremes in appearance, such as the flattened face of the Bulldog or the extremely curled tail of the Pug, seldom survive even the first crossbreeding. Mixed-breeds also tend to have a size between that of their parents.

Predicting the adult appearance of a mixed-breed puppy is difficult. Even purebred puppies do not look much like the adult dogs they will become, and with mixed-breed puppies it is nearly impossible. If one knows the breeds of the parents, some characteristics can be ruled out; for example, a cross between two small purebreds will not result in a dog the size of a Great Dane. Some breeds tend to pass on their physical traits to mixes more than others. Border Collies and some Spaniels, for example, often produce offspring with similar coats and ears. The crossbreed offspring of German Shepherds usually have Shepherd faces and other characteristics.

With each generation of indiscriminate mixing, the offspring move closer to the genetic norm. Dogs that are descended from many generations of mixes are typically light brown or black and weigh about 18 kg (40 lb). They typically stand between 38 and 57 cm (15 and 23 inches) tall at the withers.

Guessing a mixed-breed's unknown ancestry is difficult for even knowledgeable dog observers, because mixed breeds have much more genetic variation than among purebreds. For example, two black mixed-breed dogs might each have recessive genes that produce a blond coat and, therefore, produce offspring looking unlike their parents.