We tend to attribute today's zoological menagerie of dog breeds to Victorian gentlemen with a penchant for selective breeding. The truth, however, goes back much further. An international study shows that the rich morphological variety among dogs began to take off 11,000 years ago - long before nineteenth century kennel clubs.
Look at the dogs of today: the dainty Chihuahua, which most resembles a pair of eyes with fur; the magnificent Great Dane, which could almost be used as a dinner table; the bulldog's snub nose; and the elongated face of the dachshund. The variations are so extreme that it might seem odd for them all to be classified as a single species.
In a new study published in the journal Science, an international team of researchers, including researchers from the Biological Museum at Lund University, analysed 643 wolf and early domestic dog skulls using 3D geometric morphometry - which entails measuring the shape of skulls to understand how the species developed. By mapping out subtle changes in skull shape and size in three dimensions, researchers have been able to follow morphological development of dogs over thousands of years.
"Diversity among dogs isn't just a result of dog breeding during the Victorian era, it is also down to thousands of years of parallel evolution with humans. Dogs from the Holocene reflected the roles the dogs had - from hunting and herding to guarding and companionship," says Maria Mostadius, museum curator at the Biological Museum at Lund University, who contributed eleven craniums to the study.
The oldest domesticated dog skulls come from Veretye in Russia, and date back around 11,000 years. Early, varied dog morphologies have also been found in America and Asia, which shows that the dogs quickly began to diverge from wolves. Some of those early types of dog no longer exist, which suggests that lineages disappeared over time. The results of the study show that the development of the domesticated dog was a long and uneven process, which began before the first distinctly domesticated dogs appear in history.
"What's fascinating is that the very first domesticated dogs had traits that we do not see in the breeds of today. Dogs reflect our history - their development has been shaped by migration, environmental changes and societal development," says Maria Mostadius.
The researchers emphasise the need for more findings from the period 25,000-11,000 years ago, especially from Central and South-West Asia, to better understand the very earliest stages of dog domestication and the development of early lineages.
"It would of course be great to find the first dog! To understand the early diversity of dogs is also to understand ourselves - our communities, our environments and our long interaction with animals. The history of dogs is largely our own history," says Maria Mostadius.
The study was led by the University of Exeter and the French research organisation CNRS. In total, around 40 higher education institutions and organisations took part in the project, which has been underway since 2012. As well as the Biological Museum, the Historical Museum in Lund also contributed to the study.
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Link to the article in the journal Science:
