Where did horses come from?
What's the story
A new fossil DNA study has upended the long-held belief that horses were introduced to the Americas by Spanish conquistadors. The research suggests that horses actually originated in North America millions of years ago. They reached Europe through an unexpected genetic middleman in China, an extinct lineage known as the Dalian horse, according to researchers from China's State Key Laboratory of Geomicrobiology and Environmental Changes.
Genetic link
Genetic middleman
The Dalian horse, once thought to be a local oddity in northeastern China, had a unique American ancestry. It passed this on to ancient horse populations in Siberia. The researchers said, "Dalian horses likely served as one route through which North American-related genetic ancestry entered Northeast Eurasian horse populations." This means that the bloodlines leading to modern European horses got their American roots through this Chinese crossroads.
Evolutionary journey
Equids originated in North America
Equids, the family of animals that includes horses, donkeys, and zebras, originated in North America during the early Eocene. The genus Equus first appeared some 4-5 million years ago and is the only surviving lineage. Fossil records show that Equus spread from North America to Eurasia via the Bering Land Bridge about 2.6 million years ago and underwent extensive evolutionary diversification.
Migration patterns
Dalian horse's role in ancient migration
A 2025 study had already established that ancient horses migrated between North America and Eurasia during the late Pleistocene era. The new study analyzed 20 Dalian horse samples from this period, mostly excavated from Qinggang county in Heilongjiang province and Harbin. Researchers recovered complete mitochondrial genomes and identified a "distinctive component" of Eastern Beringian ancestry, essentially American DNA, that was absent from other northeast Asian equids.
Range extension
The Dalian horse went extinct around 40,000 years ago
The study also found that the Dalian horse's range extended from northern China at least northwestward to southern Siberia and northeastward to Yakutia. Despite being a genetic conduit, the Dalian horse went extinct due to its inability to adapt to a changing climate. Stable isotope analysis revealed it was a specialist grazer and couldn't survive the loss of its high-quality forage as the environment changed around 40,000 years ago.