The mystery of Spain¡¯s extinct zebra-like horses

Similar in appearance to the zebra, the cebro lived throughout the Iberian peninsula until it became extinct in the mid-16th century, with the last examples reportedly found in Albacete, in eastern Spain. But it was not until the middle of the 18th century that the cebro ¨C which in fact gave its name to the striped African equid ¨C was mentioned again, when scientists attempted to identify its origins.

Now, a group of researchers led by scientists at Spain¡¯s University of Oviedo (Uniovi) has put together information drawn from a range of disciplines, both in the sciences and humanities, that attempts to provide an up-to-date and interdisciplinary answer to the identity of this mysterious creature.

Despite the fact that Cervantes mentioned the cebro in Don Quixote, its existence remained forgotten

¡°In the 13th century, Friar Mart¨ªn Sarmiento was the first to look into the matter after he learned that the Cebreiro mountains in Galicia were known in Latin as monsdicitur Onagrorum, leading him to discover references to cebros in a large number of medieval Spanish and Portuguese documents,¡± Carlos Nores of Uniovi, the main author of a study, told science news agency SINC.

The 13th-century priest concluded that there had once been zebras in Spain. Although aware that the Spanish and African creatures were probably not the same animals, he proposed the latter¡¯s return to Spain ¡°out of curiosity and the ostentation of royal magnificence,¡± according to a document discovered in 2013.

After that, despite the fact that Cervantes had mentioned the cebro in Don Quixote, as had Lope de Vega in his The Beauty of Angelica, the animal¡¯s existence remained forgotten. It wasn¡¯t until 1922 that linguists and historians at the Lisbon Academy of Sciences called on zoologists to help clear up the matter of the cebro¡¯s origins.

In 1957, naturalist Dimas Fern¨¢ndez-Galiano lent his support to arguments that the cebro was in reality a wild ass, or onager. The only problem was that no fossils of these animals had ever been found in the Iberian peninsula.

It could have been a wild horse; an onager imported from the Middle East; or a domesticated ass returned to the wild

Half a century later, in 1992, Nores and other researchers put forward another hypothesis: that the cebro was a species of European onager, known as Equus hydruntinus, or the Otranto or European ass, which lived in southern parts of the continent during the Pleistocene epoch. Fossils of this species had been found in the Iberian peninsula dating from up to the Copper Age.

¡°But French paleontologist Eva-Mar¨ªa Geigl proved that the genuine Equus hydruntinus became extinct during the Pleistocene and that the bones attributed to this species were in reality from horses, although physically, these wild horses were very similar to the extinct Otranto ass,¡± says Nores.

The new survey, which is published in the journal Anthropozoologica, has reconstructed the morphology of the cebro and its habitat, describing its phenotype. It suggests four possible hypotheses: that the cebro was Equus hydruntinus; that it was a wild horse; that it was an onager imported from the Middle East; or that it was a domesticated horse or ass that had returned to the wild.

¡°Based on what we now know, the most plausible hypothesis seems to be that this was the last refuge of the wild horse in western Europe; in fact we know that Roman and late medieval writers noted the presence of wild horses in the Iberian peninsula in the early centuries of our era, and that their descriptions coincide with those made later that we know about,¡± says Nores.

According to the researcher, this is the most likely explanation, and is one that makes the most sense of the archeological, genetic and historical data. ¡°But future discoveries could eliminate it in favor of others, because there are still a lot of doubts,¡± admits Nores.

Which only leaves the question as to why in the Middle Ages, the cebro was considered a different animal to the horse, and compared instead with the ass or the onager? ¡°We shouldn¡¯t forget that although the domestic pig and the wild boar both belong to the same species, nobody would confuse the two, besides which, we have given them different names, as happened with the tarpan and the horse,¡± explains Nores, adding that there is nothing more appealing than a good mystery yet to be solved.