Kunga, a status symbol long before the thoroughbred

In ancient Mesopotamia 4,500 years ago, long before horses arrived in the region, another spirited member of the equine family, the kunga, took a starring role in pulling four-wheeled wagons into battle. Archaeologists had suspected that these animals  depicted in art, their sales recorded in cuneiform writing, their bodies sometimes laid to rest in rich burial sites  were the result of some kind of crossbreeding. But proof was lacking.

On Friday, a team of researchers reported on more than a decade of research in the journal Science Advances, concluding that studies of ancient DNA showed the kunga was a cross between a female donkey (Equus Africanus asinus) and a male Syrian wild ass (Equus hemionus hemippus). The kunga is the first known instance of a human-engineered hybrid of two species, a production far beyond the traditional processes of the domestication of animals, the researchers found. Eva-Maria Geigl, a specialist in ancient genomes at the University of Paris, and one of the scientists who did the study, said the breeding of kungas was really “early bioengineering” that developed into a kind of ancient biotech industry. Like mules, which are hybrids between horses and donkeys, and which were created much later, the kungas were sterile. Each new kunga was a one-off, a mating between a wild ass stallion and a donkey.

The stallions had to be captured and kept in captivity, even though they were highly aggressive, as modern records have indicated. Dr. Geigl said that the director of a zoo in Austria, where the last captive Syrian wild asses died, described them as “furious.” Archaeological records show that a breeding center in Nagar (now Tell Brak, Syria) shipped the young kungas to other cities. They were costly animals, status symbols, and were used in war and military ceremonies.

Kungas held their high status for at least 500 years, Dr. Geigl said. Horses did not appear until around 4,000 years ago to take their place in battle and ceremony, and to contribute to the creation of other hybrids. Before the current research, the oldest known hybrid was a mule from a site in Turkey dating to 3,000 years ago. Members of the same team reported on that find in 2020.

The research team had to cope with the very poor preservation of fossils from desert areas, but used a variety of techniques to examine ancient DNA. Laurent Frantz, a paleogenomics expert at Ludwig Maximilian University of Munich, who was not involved in the study, said that despite these difficulties, the “results were very convincing,” showing that people “were experimenting with hybrid equids long before the arrival of the horse.”

Fiona Marshall, an archaeologist at Washington University in St. Louis, who has researched the prehistory of donkeys and their domestication, said the study was “enormously significant” partly because it showed that the breeders had clear intentions. The early process of domestication was always murky — probably part accident, part human intervention — but this research showed what the ancient Syrians were after. “People wanted the qualities of a wild animal,” she said. Donkeys might have been tamer than their ancestors, the African wild ass, but the breeders in Mesopotamia wanted to back breed to other wild asses for strength and speed — and perhaps size. Although the last known living examples of the Syrian wild ass were very small, a little more than three feet at the withers, older animals of the same species were larger.