Sulphur Mustangs: Historic links to North Africa

In the final part of a study investigating the origins of North America’s Sulphur Mustangs, Dr Mitch Wilkinson looks to North Africa. He also warns that without a united front to protect them, the wild horses may be doomed to extinction. “As unique as they are, and as ingrained in the history of the Southwest as they have been, very few people have even heard of Sulphur Mustangs. They may be gone before the public even realizes they were ever there.”
Because of their close proximity and shared history, Morocco and Spain have been closely linked for millennia. This relationship was very evident during the Moorish occupation of Spain, which lasted over 800 years from 711 AD to 1492 AD. The Moorish name for Southern Spain was Al-Andalus, from which the province of Andalusia derived its name. This relationship between the two cultures continued during the century of Spanish colonization of New Spain as it had a thousand years before when both areas were part of the Roman empire.
The link between Spanish horses and the Barb horses of North Africa is strong, but the most vital link is not between today’s modern Spanish horse breeds and Barb horses but between the now-extinct Spanish Jennet and Barb horses. North American Spanish Colonial horses are linked to Barb horses by their shared Jennet ancestry. Sulphurs and other Colonial Mustangs are the living descendants of those horses who no longer exist in Iberia. Those same early Iberian horses greatly influenced the development of the Barb horse of North Africa.4
Here’s how it happened
One might think the narrow eight-mile straight between Gibraltar and Morocco is a recent geological feature and that horses and other animals traveled on a land bridge between Europe and North Africa in the distant past, but nothing could be more incorrect. The land bridge between the continents was flooded during the beginning of the Pliocene Epoch around 5.35 million years ago. Once the rising waters of the Atlantic breached the land bridge, the subsequent erosion caused by billions of gallons of water flooding into the Mediterranean basin meant the land bridge could never exist again. Modern equines (Equus caballus) began their development in North America a few millennia before, so there were no modern horses to cross the land bridge even when it existed. The close relationship between Iberian horses and North African horses did not come from the natural forces of nature, but rather from humanity’s influence over the centuries.15
Because of the proximity of the two continents, there must have been horse exchanges throughout antiquity, but we do not have documentation of those early exchanges. The first historical records occurred during the Punic Wars between Rome and Carthage, which lasted from 264 BC to 146 BC. The Carthaginians established a kingdom in Iberia from 237 BC to 222 BC. From this kingdom, Hannibal launched his attack on Rome with North African elephants and 6000 Iberian and North African cavalry. After Carthage’s defeat at the hands of the Romans, the Iberian Peninsula became part of the Roman empire and was named Hispania. The North African coast also fell under Rome’s control and was named the province of Africa Proconsularis.16
The Romans quickly realized the value of the horses found in Hispania, but the horses found in Africa Proconsularis were much fewer in number and of poorer quality. Because it is only a day sail from Southern Spanish ports to Africa, it only took a short time before Iberian horses were brought to Africa Proconsularis to improve the existing horses of the province. This was the beginning of the North African Barb. Horse breeding operations were conducted in both provinces for the next 500 years of Roman rule. The province of Hispania specialized in cavalry mounts and horses for officers and wealthy Romans. The province of Africa Proconsularis specialized in chariot horses, but horses from both Hispania and North Africa were used in the games.

Chariot racing was by far Rome’s most popular sport. Horses, drivers, and trainers were national celebrities. The precursors of today’s Barb and Hispanic horses were immortalized in sculpture and inscriptions throughout the empire. Horses were routinely exchanged between the two provinces for breeding and training.17
By the third century AD, Rome was in decline. The Huns forced the displacement of the Suevi and Vandals from central Europe. Consequently, these tribes fled to Iberia in 410 AD. The Visigoths soon followed the Vandals. The Vandals did not stop with the conquest of western Spain. Attracted to the wealth of the province of Africa Proconsularis, the vandals loaded Iberian horses on ships by the thousands. They took Iberian horses to Africa to aid in the conquest of the province. Some mistakenly think the Visigoth tribes invaded North Africa, but actually, it was the Vandals who invaded. Vandals were also a Gothic tribe like the Visigoths. Around 80,000 Vandals invaded Rome’s African province. The Vandal and Visigoth military strength rested with heavily armored foot shoulders, but they also used cavalry and needed horses to transport supplies. Thus, another introduction of ancient Iberian horses came to North Africa to influence the ancestors of the Barb horse. Eventually, the Byzantine Empire reconquered Africa Proconsularis, but the Muslim invasion of North Africa soon displaced them.18

In 711 AD, the Moorish invasion of Iberia began. Muslim chroniclers of the time describe the Christian horses of Iberia as bigger, better, and more numerous than their North African horses, which they left at home. The initial invasion of Iberia only included about 100 North African horses. The horses that the Moors used during the conquest of Spain were indigenous Spanish horses, not the precursors of Barbs from North Africa.4
For the next 800 years, the Moors took Spanish horses back to North Africa to improve the native horses of North Africa and as gifts to Muslim royalty. At the time, Iberian horses were considered far more valuable than African horses. The Moors established large breeding farms near their capital, Cordoba, and in the Emirate of Granada. Interestingly, the Moorish breeding farms were operated by native Iberians, not Moors, who had only an administrative role. The native people of Spain were considered better horse handlers and trainers by the Moors.27 It was under the centuries of Moorish rule that the Spanish Jennet was developed and refined23. The term “Spanish Barb” shows a fundamental misunderstanding of the events which occurred in Muslim Iberia27. Barb horses were never imported to Iberia in great numbers. Instead, the reverse is true. The Southern Iberian horse greatly influenced the Barb horse of North Africa and was exported to Africa19,25. The “Spanish Barb” existed, but it existed in North Africa, not Spain.
The influence of Iberian horses on North African Barbs was almost continuous from the time of the Romans, the Vandals, and finally, the Moors, so much so that Spanish horses of the 15th century were extremely close to North African horses of that time. The reconquest of Spain, known as the “Reconquista”, did not stop with Granada in 1492. While Columbus was exploring the New World, the Spanish Court dreamed of liberating the Holy Land. The Spanish took the African city of Medillia in 1497 AD.
From 1508 AD to 1510 AD. Spanish forces besieged major cities all along the coast from Algiers to Tripoli20. Iberian horses were again taken to North Africa for the war effort by the thousands. These horses would have been the very horses taken to the New World, including the horse we call today the “Spanish Jennet”. Spanish horses of the time played an essential role in both colonial undertakings by the Spanish Empire. In the New World and North Africa, many soldiers who took part in the armies of the conquistadores also fought in North Africa. Pedrarias Davila, the conquistador of Panama and Nicaragua, served in Spain’s 14-year-long North African crusades before going to the New World. After returning from Mexico, even Hernán Cortés sailed with King Charles V in the attack against Algiers in 154121.
Today, Spain still has two protectorates in North Africa. The semi-independent city-states of Ceuta and Melilla are considered part of Spain. During the Spanish Civil War, Francisco Franco’s Moroccan troops became the core of the Spanish Nationalist Army22. Considering a 2000+ year history of Iberian-African interaction, it is no wonder that Barb horses are closely linked to Spanish horses. Recent studies have also linked Barb horses to certain American mustangs like the Sulphur horse through their mutual Spanish ancestors. Even though special populations of American mustangs are not Barb horses from North Africa, the current North American Colonial Spanish horse, such as the Sulphur, is closer to the modern Barb horse of North Africa and its progenitor, the 15th-century Spanish Jennet than it is to modern Iberian horses like the Andalusian, Lusitano, or Marismeno which have changed so drastically over the centuries. It must be emphasized that all these horses are related. The D1 mtDNA haplogroup (Jansen; et al.2002) is associated with breeds of horses from the Iberian Peninsula and Northern Africa. Although not exclusively found in just these breeds, 50% of Andalusians, 56% of Lusitanos, 54% of North African Barbs, and 31% of American mustangs were found to have the D1 haplogroup, which implies intermixing. In the case of American Colonial Mustangs, mtDNA studies show many founding mares came from these groups28,24. To quote Dr Deb Bennett29: “ The mustang, in short, is not the descendant of the Andalusian, if by that term you mean the breed as it now is. Rather, the mustang and the modern Andalusian both trace back to the Jennet, their mutual ancestor in medieval Spain.”
The last PCoA graph below shows the relationship between modern Andalusian horses, Moroccan Barb, Algerian Barb, Tunisian Barb, and Sulphur Mustangs.

The horses depicted in Fig. 13 all had a common ancestor back in Roman times and possibly before. The Andalusian component was influenced by the addition of European Warmblood that continued up to Napoleonic times. The Algerian Barb had more horse types added, predominately Arabian and Thoroughbred, and therefore differentiated from the original Barb horse. The Tunisian Barb was not influenced by additional breeds added to the population to the degree that Andalusian and Algerian Barb experienced. The graph shows that the most compact population is the Moroccan Barb. It is positioned like the center of a wheel. The other groups revolve around it, including Sulphur. The Sulphur possesses a component of the original ancestorial horse. Like the other groups, the Sulphur Mustang had outside influences that allowed it to deviate in another direction in its development.
The overlap of the various populations implies a common origin, especially in the case of the Andalusian and Barbs. Exchanges between the populations that matched the historical records are reflected in the graph. At the time of Columbus, the differences in these populations were not as significant as today. However, over the past 500 years, each population pursued its own destiny and differentiated from its fellows.

Conclusion
So what are Sulphur Mustangs? They are close to the Andalusian, Lusitano, and Barb horses because they had a common ancestor that dates back to Roman times. The relationship between Spanish horses and North Africa was accentuated from the 8th century to the 16th century through Spanish-North African exchanges in war and trade. Distinct groups of American horses include Sulphur Mustangs and their cousins such as the Baca, Wilbur-Cruce, and Grand Turk Island horses, and probably several more strains had a common ancestor, the 15th-century Spanish Jennet.
The predecessors of the Sulphur Mustangs and their cousins began their journey in the New World on the Islands of the West Indies, where their ancestors were bred from ancestral Marismeno horses, common southern Spanish horses of the time, possibly pinto-colored horses from France, and horses called today “Spanish Jennets”. At some point, they were mixed with Northern Spanish Celtic ponies such as the Galician Pony, although historical records corroborating importation from Spain have yet to be found. There is a chance that the Celtic Pony bloodlines came from the original Jennet, but testable archeological samples must be located to rule this out. These horses followed the conquest and subsequent colonization of North and South America from the West Indies with their Spanish masters. This new type of horse, called in this paper a Caribbean Criollo, went on to inhabit Northern Mexico and the American Southwest and became the original Spanish Mustang of Western legend.
So Sulphur horses are an altered remnant of Spanish horses from the colonial era of Spain. Conquistadores would have recognized them as the horses they knew. They are derived from Iberian horses but are mixed Iberian horses. Since the concept of a “breed” began in Spain in the 16th century, Spanish records may never be found designating the type or origin of horses imported to the colonies. Horses shipped to the Spanish colonies came from several Iberian types and were just horses. A conquistador would have called his horse a “horse from Aragon” or a “horse from Granada”. Through the centuries, other horse breeds have been added to the original Sulphur population. Their Spanish Jennet ancestor is now extinct. In the case of the Galician and other Northern Iberian Celtic ponies, their predecessors are very endangered. Only the Marismeno horse, managed from the time of Columbus by the citizens of Almonte, Spain, is not in danger of extinction.
The history uncovered in this investigation into the genetic components of these horses is less romantic than surviving Pleistocene Era horses or the finest Spanish horses from Iberia that somehow ended up in Utah. Nevertheless, it is a remarkable tale of survival until modern times. It is a tale of the horses that first returned to the New World, where all equines originated. They have managed against all odds to survive for the past 500 years, and now, their long-term survival is threatened.
The future
In February of 2022, the Bureau of Land Management (BLM) conducted a gather that removed nearly 200 Sulphur Mustangs from their Needles Mountain home. Was it justified? I do not have enough facts to have an opinion, but I do have an opinion about the results of this study. In graph after graph, Sulphur Mustangs and their cousins Baca, Wilbur-Cruce, and Grand Turk were found to be genetically distinct horses not closely related to any other breeds. The preponderance of evidence makes them unique, and by being unique, they deserve preservation.
It is up to the breeders, the public, adopters, and registries to preserve these beautiful horses for future generations. We cannot leave it to government mandates which may never happen. Without a united front, the few remaining horses are doomed to extinction. We can’t let this happen because of personality conflicts between preservationists. Everyone should realize: as unique as they are, as beautiful as they look, and as ingrained in the history of the Southwest as they have been, very few people have even heard of Sulphur Mustangs. They may be gone before the public even realizes they were ever there.

Acknowledgments
I wish to thank Dr Gus Cothran and Dr Rytis Juras. Without their help, this paper would not be possible. The cooperation from private Sulphur horse owners was critical in completing these PCoA studies, but their love of the remarkable Sulphur horses in their care will become their lasting legacy.
Dr Mitch Wilkinson, a lifelong horse enthusiast with a post-doctoral master’s degree from Baylor University in biology, as well as dental and chemistry degrees, is chairman of the Curly Mustang Association, vice-chairman of the Research Department of the International Curly Horse Organization (ICHO), and Research Coordinator for the Sulphur Springs Horse Registry.
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Again, greatly appreciate this lucid analysis based on historical knowledge and meticulous genetic analysis. We must save the unique Sulphur mustangs. They are a priceless living heritage as well as a valuable balancer and restorer of the western North American ecosystems they inhabit. It was a real sacrilege for BLM, under pressure from overbearing public lands ranchers, to gut this small, precious remnant herd in February of 2022. I suppose all of the stallions and mares were sterilized — another despicable blow to the wonderful mustangs of America and an utterly blind and destructive act by people who lack wise perspective on what matters most as well as higher sensitivity and compassion!