Oldest Mule Remains Found in Spain Reveal Ancient Breeding Practices

Around February 11, 2026, a remarkable archaeological discovery is shedding new light on the history of animal husbandry and early Mediterranean exchange. Researchers have identified the oldest remains of a mule in Western Europe, dating back approximately 2,700 years. The find, made at the Iron Age site of Hort d’en Grimau in northeastern Spain, offers a unique glimpse into the practices of early animal breeding and the interconnectedness of ancient societies.

The remains, consisting of a skull and associated skeletal fragments, were initially excavated in 1986 from a pit that had been repurposed from a grain silo. Recent genetic analysis confirmed the animal as a female mule – a hybrid offspring resulting from the breeding of a male donkey and a female horse. This discovery pushes back the timeline for known equid hybridization in Europe by several centuries.

Mules, while possessing the strength of a horse and the hardiness of a donkey, are typically sterile. Successfully breeding them required a deliberate and skilled approach, involving the training of male donkeys from a young age to mate with mares. This inherent difficulty made mules particularly valuable throughout history, as noted by the study authors.

Prior to this discovery, the oldest known mules were found in the Middle East, with evidence dating back over 4,000 years. The presence of a mule in Iron Age Iberia suggests that knowledge of this breeding technique, originating in the Near East, spread westward earlier than previously thought. The researchers believe the Phoenicians, seafaring traders active in the region during this period, may have played a role in introducing both donkeys and the knowledge of mule breeding to the Iberian Peninsula.

The archaeological context of the find is particularly intriguing. The mule was buried alongside the partially cremated remains of a young woman, estimated to be between 20 and 25 years old at the time of her death. The woman’s remains were fragmented and deposited with stones and ashes, a funerary practice that differs from the typical full cremation and urn deposition common during that era. The mule itself showed no signs of cremation.

Analysis of isotopes present in the mule’s bones revealed that it was fed a diet rich in cultivated cereals, indicating intentional foddering and likely stabling. Anatomical examination of the skeletal remains showed evidence of age-related pathologies, specifically in the jaws, consistent with regular use for riding. This suggests the mule was not merely a working animal, but one that held a degree of social value.

“The mule shows clear evidence of having been ridden and well‑fed, suggesting that it held considerable social value,” explained F. Javier López Cachero, an archaeologist at the University of Barcelona and co-author of the research.

The reasons for the unusual burial arrangement – a mule interred with a partially cremated woman – remain a mystery. While horses were sometimes found in burials in the ancient world, often associated with warrior status, the significance of a mule in this context is unclear. The researchers emphasize that the limited archaeological evidence prevents definitive conclusions about the woman’s social standing or the reasons for this unique pairing.

“The funerary treatment of the human remains is ‘unconventional’ and the absence of grave goods prevents any firm conclusions regarding the woman’s social status,” López Cachero stated.

This discovery highlights the complex interactions between humans and animals in the ancient world, and the role of animal hybridization in shaping early agricultural practices and trade networks. The presence of a well-cared-for mule, deliberately bred and utilized for riding, underscores the ingenuity and resourcefulness of early Iberian communities and their connections to broader Mediterranean exchange systems. Further research at the Hort d’en Grimau site and analysis of similar archaeological finds will undoubtedly contribute to a more complete understanding of this fascinating period in history.