Why Did the Chicken Cross the Red Sea? Genetic Diversity of Fowls Explained

Researchers from Washington University in St. Louis have discovered chicken bones from Ethiopia that could explain how domesticated chickens crossed ancient roads and seas.

Discarded bones of a chicken leg that were etched with teeth marks from a meal thousands of years ago provide one of the oldest known physical evidence for the introduction of domesticated chickens to the continent of Africa. This was confirmed by the radiocarbon dating of about 30 chicken bones unearthed at the site of an ancient farming village in present-day Ethiopia.

"Our study provides the earliest directly dated evidence for the presence of chickens in Africa and points to the significance of Red Sea and East African trade routes in the introduction of the chicken," explained Helina Woldekiros, lead author and a postdoctoral anthropology researcher in Arts & Sciences at Washington University.

The red junglefowl Gallus gallus, widely considered to be the main wild ancestor of today's chickens, was first domesticated 6,000 to 8,000 years ago in sub-Himalayan northern India, southern China, and Southeast Asia. This species of domesticated chickens gives modern researchers valuable clues about ancient agricultural and trade contacts.

"It is likely that people brought chickens to Ethiopia and the Horn of Africa repeatedly over long periods of time: over 1,000 years," Woldekiros said. "Our archaeological findings help to explain the genetic diversity of modern Africans chickens resulting from the introduction of diverse chicken lineages coming from early Arabian and South Asian context and later Swahili networks."

Chickens that have been featured on ceramics and paintings suggested that chickens were first introduced to Africa through North Africa, Egypt, and the Nile Valley about 2,500 years ago. The earliest evidence of chicken bones in Africa could be traced to approximately 685 to 525 B.C. from the Saite levels at Buto, Egypt.

"Our study also supports the African Red Sea coast as one possible early route of introduction of chickens to Africa and the Horn," Woldekiros said. "It fits with ways in which maritime exchange networks were important for global distribution of chicken and other agricultural products. The early dates for chickens at Mezber, combined with their presence in all of the occupation phases at Mezber and in Aksumite contexts 40 B.C. to 600 A.D. in other parts of Ethiopia, demonstrate their long-term success in northern Ethiopia."

The findings of Woldekiros support the possibility of the many ways in which people transport domestic animals around the world through migration, exchange, and trade.