PRE-CONTACT DOGS: The Chihuahua

The keys to the new study, published in the journal Proceedings of the Royal Society B, were mitochondria—the energy powerhouses of the cell—and specifically mitochondrial DNA, which is usually inherited from the maternal line.

An isolation-by-distance best characterizes how dogs expanded into South America. We identify the arrival of new lineages of dogs in post-contact South America, likely of European origin, and their legacy in modern village dogs. 

• Interestingly, the Pre-Contact Meso-American maternal origin of the Chihuahua has persisted in some modern individuals. 

How One Chihuahua Proved to Be a Link to the Ancient Dogs That Moved to Latin America With the Spread of Agriculture

A handler holds her Chihuahua dogs in the grooming area at the 149th Annual Westminster Kennel Club Dog Show at Jacob K. Javits Convention Center on February 10, 2025, in New York City.  Andres Kudacki

New research shows that ancient dogs did not join Indigenous people in Central and South America until farming became popular—especially of maize

[...] 

From the sixteenth century onwards, the introduction of dogs by the European settlers impacted the population of pre-contact dogs, whose genomic signature is now almost completely diluted in European dogs ancestry.

 One notable exception are Chihuahuas that still carry, for some individuals, a pre-contact maternal line, providing evidence of their Mexican origin.

This study sheds new light on the depth of the shared histories of human societies and dogs in the Americas and highlights the importance of agrarian societies in the spread of dogs. While dog domestication is intrinsically associated with hunter–gatherer groups [76,78], there is a growing body of evidence that early farmers were instrumental for dog dispersal. A similar pattern has been found in East Asia, where dog population expansion around 7500 BP has been associated with the spread of agricultural communities across the region and a growth in food supply [90].

Ancient dog mitogenomes support the dual dispersal of dogs and agriculture into South America

Aurélie Manin

,

Regis Debruyne

,

Audrey Lin

,

Ophélie Lebrasseur

,

Evangelos Antonios Dimopoulos

,

Lucio González Venanzi

,

Sophy Charlton

,

Lachie Scarsbrook

,

Andrew Hogan

,

Anna Linderholm

, … See all authors

 

Published:18 June 2025https://doi.org/10.1098/rspb.2024.2443

Review history

Abstract

Archaeological and palaeogenomic data show that dogs were the only domestic animals introduced during the early peopling of the Americas. 

• Hunter–gatherer groups spread quickly towards the south of the continent, but it is unclear when dogs reached Central and South America. 

To address this issue, we generated and analysed 70 complete mitochondrial genomes from archaeological and modern dogs ranging from Central Mexico to Central Chile and Argentina, revealing the dynamics of dog populations. 

 

Our results demonstrate that pre-contact Central and South American dogs are all assigned to a specific clade that diverged after dogs entered North America. 

• Specifically, the divergence time between North, Central and South American dog clades is consistent with the spread of agriculture and the adoption of maize in South America between 7000 and 5000 years ago. 
• An isolation-by-distance best characterizes how dogs expanded into South America. 

We identify the arrival of new lineages of dogs in post-contact South America, likely of European origin, and their legacy in modern village dogs. 

Interestingly, the pre-contact Mesoamerican maternal origin of the Chihuahua has persisted in some modern individuals.