Dogs 10,000 years ago roamed with bands of humans and came in all shapes and sizes

From country dogs to toy poodles and mastiffs, dogs come in an amazing variety of shapes, colors and sizes. Today it is estimated that there is about 700 million dogs live with or near people.

For many of us, dogs are loyal companions, work partners and beloved family members, and the histories of our species are deeply intertwined. But how did this incredible diversity come about – and how far do these relationships with people go?

Two new studies published today in Science give some answers. One of them, led by Allowen Ewin of the University of Montpelier, relies on remains of ancient skeletons. Another, led by Shao-Jie Zhang of the Kunming Institute of Zoology, draws on research DNA of ancient dogs of Eastern Eurasia.

Taken together, these studies suggest that the history of dogs and their relationships with humans is older and more complex than previously thought.

Origins of modern dog diversity

study Evin and her colleagues used 643 dog and wolf skulls from the last 50,000 years to explore the origins of modern canine diversity.

Analysis of her command suggests a characteristic “dog-like” scull The form first emerged about 11,000 years ago, during the Holocene epoch, after the last ice age. They also found significant physical diversity in dog skulls from the same period.

This means that the wide range of dog shapes and sizes today is not only the result of intensive selective breeding programs that have become popular in the last few centuries. Some of these variations originated thousands of years earlier.

The team re-analyzed the skull shapes of all 17 known dog and wolf skulls from the late Pleistocene, a geological period from 129,000 to 11,700 years ago. Some of the skulls were 50,000 years old.

They found that all of these Pleistocene skulls were shaped like wolves, including some previously identified as early dog ​​skulls.

Importantly, this suggests that while the split between wolves and dogs likely occurred during the Pleistocene, the skull shape of early dogs only began to change towards the Holocene, 11,000 years ago. However, some Holocene dog skulls still retained wolf-like features.

This research shows that early dogs were much more diverse than previously thought. This diversity may have laid the foundation for the extreme differences in dog sizes and shapes that we have today.

Travel companions

Previously genomic research discovered four main lineages of dogs that likely arose about 20,000 years ago: eastern (East Asia and the Arctic) and western (Europe and the Middle East) dogs.

origins of these ancient dog lines are still unraveling. However, studying changes in the origins of dogs over time and between different regions can help us better understand both the origins of dogs and the movements of Neolithic (New Stone Age) people.

New study Zhang and his colleagues used 73 genomes of ancient dogs spanning the last 10,000 years to study how humans and dogs moved through eastern Eurasia through time.

Analysis of these ancient dogs has revealed multiple shifts in the origins of dogs in Eastern Eurasia, at times correlating with the movements of specific groups of people (hunter-gatherersfarmers and pastoralists). This suggests that as different human cultural groups moved across Eurasia, their dogs often moved with them, carrying their own unique genetic characteristics.

In some parts of Asia there was some discrepancy between the origins of humans and dogs. For example, the eastern hunter-gatherers of Veretye ​​and Botai, who were more closely related to the people of western Eurasia, had mostly eastern (Arctic) dogs, rather than the western dogs observed in other western Eurasian cultures at the time.

This means that dogs may have been a key part of cultural exchange or trade between different human cultures or communities. It may also illustrate the complexities of dog evolution that we have yet to understand.

Zhang and his team's work provides compelling evidence that in eastern Eurasia thousands of years ago, dogs played an indispensable role in human society as essential “biocultural packages” that moved with people. In other words, people took their companions with them on their travels (and perhaps traded them), rather than simply acquiring new dogs after moving.

These findings highlight the long-term, complex and intertwined relationship between dogs and humans that dates back more than 10,000 years.

The genetic origins of dogs can serve as living evidence of ancient human migrations, trade networks and cultural exchanges. Research on ancient dogs can also help us understand the environmental factors that contributed to the evolution of dogs and their relationships with humans.

Changing our understanding of dogs

Taken together, these new studies profoundly change our understanding of how dogs became so diverse and how they interacted with humans along the way.

Both studies highlight that the incredible diversity of modern dogs is not an entirely recent phenomenon. The genetic and morphological foundations of this variation were laid thousands of years ago by natural selection, human selection and environmental diversity, long before the structured breeding of the last few centuries.

Future studies examining the physical diversity and origins of dogs over time could deepen our understanding of the complex origins and distribution of dogs around the world. Whatever their origins, this research deepens our understanding of the unique and ancient bond between humans and dogs, which was almost as diverse as dogs themselves.

This article has been republished from Talk under Creative Commons license. Read original article.