June 20, 2025, 9:11 am | Read time: 6 minutes
When did the first dogs arrive in South America, and what remains of them today? A study on the origins of dogs in the Americas reveals that they did not arrive with the first humans but came later with agriculture—and nearly all traces of their genes have been lost. Only one representative carries their ancient heritage.
How and when did dogs arrive in South America? A genetic study provides astonishing answers: The animals did not come with the first humans but thousands of years later. The genetic trail of the dogs of the indigenous population leads to a surprising discovery: only the Chihuahua, but not the hairless dogs of South America, still carry the genetic material of these early companions.
How Dogs Came to South America
When talking about American dog breeds today, many think primarily of dogs like the Boston Terrier or the American Wirehair—and implicitly of the U.S. and its dog breeding. However, the history of dogs on the American continent began long before the modern breeds of today and indeed with the earliest human settlement of the continent at least 15,000 to 16,000 years ago.
Back then, dogs accompanied humans as the first and only domesticated animals across the Bering Land Bridge. Genetically, they belonged to the so-called A2b lineage—a mitochondrial lineage that developed only in America. But archaeological findings show: While humans quickly spread to South America, dogs appeared there much later. Their arrival coincides with the advent of agriculture, but it was unclear whether this was coincidence or connection.
Additionally, many fossil remains are difficult to definitively identify as dogs, as many wild canids also lived in America—such as coyotes or foxes, as well as extinct species. Previous genetic studies focused on North America, while ancient DNA from South America was largely missing. This new study fills that gap and provides exciting insights into indigenous dogs in America.
Spread of Dogs in South America Follows Corn Cultivation
An international research team led by Aurélie Manin (University of Oxford) analyzed 70 mitochondrial genomes of ancient and modern dogs from Central and South America. The results were published in 2025 in the journal “Proceedings of the Royal Society B.” The aim was to reconstruct the temporal and geographical spread of dogs on the American continent. The team discovered a remarkable connection: The spread of dogs apparently did not occur in isolation but alongside the rise of agriculture, particularly corn cultivation—about 7,000 years ago.
The researchers analyzed DNA from a total of 131 archaeological dog bones and 12 modern dogs found in an area from central Mexico to Patagonia. Using modern sequencing techniques, they reconstructed 70 complete mitochondrial genomes—62 from archaeological finds, eight from contemporary dogs.
Dogs in South America Developed Independently from North America
The genetic identification was secured by comparison with other canid DNA sequences. The scientists then reconstructed the family trees and the temporal development of the lineages. They examined in detail whether the distribution patterns could be genetically explained by so-called isolation-by-distance models (spread along geographical distances).
Genetically, the dogs from Meso- and South America formed a closely related group (A2b1a). This group split from North American lines about 7,000 to 5,000 years ago. This timeframe coincides exactly with the period when corn and agriculture spread from Mexico to South America. Initially, this occurred along the coasts, but especially west of the Andes. Dogs were only found later in the eastern regions of South America.
The genetic data clearly show: All dogs that lived in Central and South America before the European conquest (referred to in the study as “pre-contact dogs”) belonged to the mitochondrial lineage A2b. However, this lineage split into four further genetic groups, with A2b1 found only in South America.
Chihuahua Carries Genetic Markers from 5,000-Year-Old Relatives
In southern South America (especially east of the Andes), a later genetic branch can be observed. The common ancestor of these animals existed about 2,200 years ago, around the time when the Mayan civilization began to develop. However, it could not be determined what these dogs looked like or to which breed they might belong.
In all modern dog samples—researchers particularly highlight Peru here—the original lineage was no longer detectable. They attribute this to the introduction of European dog breeds that arrived with the conquerors. The A2b1 lineage from South America almost completely disappeared. However, a modern Chihuahua from the U.S. and a farm dog from Mesoamerica are exceptions. These two animals showed millennia-old genetic markers.
However, these data also refute assumptions that the Peruvian and Mexican hairless dogs (Xoloitzcuintle) are nearly as old as proponents of these breeds claim. The absence of the A2b1 lineage after 1492 in Peru speaks volumes. It is also proven that the Xoloitzcuintle, first exhibited in 1863, is no longer related to indigenous dogs of Mesoamerica but primarily possesses genetic material from the shepherd dog. The study clearly showed that these dogs could not have originated before the conquest of the Americas.
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Conquest of the Americas Led to the Near-Complete Loss of Indigenous Dog Breeds
The study provides the first comprehensive genetic reconstruction of the spread of dogs in Central and South America. The crucial insight is that dogs did not come to South America with the first humans but significantly later—together with agriculture.
The genetic lineage A2b1 and the remaining groups show that these dogs were a genetically homogeneous group that subsequently diversified regionally. The researchers also demonstrate that there was no significant transmission of the A2b lineage after the arrival of Europeans. Their genetic traces almost completely disappeared, likely due to the genocide of the indigenous population and the introduction of European dogs.
Only a few modern dogs, like the Chihuahua, still carry remnants of this ancient genetic lineage. The findings support the theory that dogs spread in close connection with early agricultural societies. This is similar to what has been described for domestication in Eurasia and Africa.
This shifts the focus to the role of agrarian societies: They were the ones who brought dogs to South America and integrated them closely into their culture. Future studies with nuclear DNA could further illuminate this fascinating chapter of human-animal history. They could also examine whether the genetic markers have been preserved in more dogs. 1