The utility of domestic dogs in assessing human morphological variation

Although distantly related to us, dogs are a highly variable cohabitating taxon that may provide clues relevant to hypotheses of human variation, evolution, and development. Here we first propose the utility of domestic dogs as a heuristic model for the study of human variation and evolution. Next we provide a case study of variation in a mandibular relationship previously suggested to distinguish Neanderthals from modern humans taxonomically. We show that for dogs varying greatly in size and form, this character (the relative heights of the condyle and coronoid process) does not produce useful group divisions. While this result cannot disprove the taxonomic value of this character for humans/hominids, it does indicate that caution is warranted in accepting it as genetically constrained. Similar explorations of other features of domestic dogs may prove fruitful in elucidating aspects of human variation and evolution not readily highlighted by primate and fossil hominid studies. Expected ranges of variation and degrees of plasticity are key questions to be investigated.