Dogs came in a wide range of sizes and shapes long before modern breeds

Dogs have long captivated us with their astonishing diversity in shapes and sizes. For instance, a Borzoi and a Boston terrier seem worlds apart, yet they share a fundamental canine essence that unites them. Recent research reveals that this variety among dogs existed much earlier than previously thought. A comprehensive study examining dog and wolf skulls from the past 50,000 years indicates that even shortly after the last Ice Age, dogs exhibited a remarkable range of physical traits, about half as varied as contemporary breeds. Led by biologist and archaeologist Allowen Evin from CNRS, the research team analyzed 643 skulls—158 belonging to modern dogs, 86 to modern wolves, and 391 unearthed from archaeological sites worldwide. By assessing specific skeletal features, the researchers quantified the differences in size and shape among the skulls, shedding light on the evolutionary trajectory of dogs, particularly their cranial forms. The findings suggest that dogs from the Mesolithic era, prior to the advent of settled agriculture in the Middle East, and the Neolithic era, when farming began to flourish, were surprisingly diverse in skull shape and size. Through statistical analysis, it was revealed that these ancient canines possessed skulls that were roughly twice as varied as their Pleistocene ancestors and demonstrated a diversity that was already over half of that seen in modern breeds. Evin shared insights with Ars, noting that some ancient dog skulls exhibited shapes that have no counterparts among contemporary breeds. This suggests that these early canines may have adapted to specific regional environments or functions that have since vanished. Although ancient dogs did not display the extreme features evident in some modern breeds, such as the pug, the level of variation was unexpectedly high. Today, hundreds of distinct dog breeds exist, shaped largely by careful breeding practices that gained prominence during the Victorian era.