What Should Dogs Look Like? Welfare Consequences of Canine Morphology

The domestic dog has been intensively selectively bred since the Victorian era for morphological traits. Questions about the implications on canine welfare of some of those traits have been asked since that time. More recently, legislation has been proposed and enacted in several countries to guide selection for specific morphologies. We describe common canine phenotypes with associated disorders and the biological mechanisms driving those disorders. We additionally describe opportunities for further study identifying which ranges of morphologies support robust canine health while still preserving the uniqueness of different breeds. Focusing on morphologies with a range of expression, rather than focusing on harmful characteristics prevalent in particular breeds, is a new perspective on canine welfare which we expect to support evidence-based efforts to set future breeding goals, and to increase awareness of these issues by the people who purchase (and love) dogs.