Ancient Egyptians mummified millions of birds. Where did they get them?

Between roughly 650 and 250 B.C., ancient Egyptians sacrificed staggering numbers of mummified ibises to Thoth, god of magic and wisdom, who was depicted with a human body and the distinctive long-beaked head of the bird. Archaeologists have found literally millions of these votive offerings in ancient Egyptian necropolises, where the bird mummies were interred after being offered to Thoth to cure illnesses, gift long life, or even sort out romantic troubles.

“I often compare it with the candles lit in Christian churches,” says University of Oxford archaeologist Francisco Bosch-Puche, part of a team that has excavated thousands of ibis mummies from the necropolis of Dra Abu el-Naga. “The [ibis] mummy would remind the god that they needed to take care of you.”

Due to the sheer scale of the ibis mummy industry, many Egyptologists have assumed that the bird—specifically the African sacred ibis (T. aethiopicus)—was deliberately bred in large centralized farms. This assumption has been bolstered by archaeological and textual evidence for large-scale bird-raising operations. However, a study published today in the journal PLOS ONE suggests that most ibises were actually captured in the wild and possibly kept on farms for only short periods of time before being sacrificed and mummified. This new insight into how ancient Egyptians may have sourced the birds on such an enormous scale could impact the way researchers think about the ancient animal mummy industry, and also help illuminate how and why the sacred ibis eventually became extinct in Egypt.

The study, led by paleogeneticist Sally Wasef of the Australian Research Centre for Human Evolution at Griffith University, examined the DNA of 40 mummified ibises dating to around 481 B.C. from six Egyptian catacombs sites including Saqqara (where more than 1.5 million mummified ibises were deposited), and Tuna el-Gebel (home to approximately four million ibis mummies). The ancient DNA was then compared with 26 genetic samples from sacred ibises in modern African bird populations outside of Egypt.

The DNA analysis revealed that the mummified birds of ancient Egypt had a genetic diversity similar to that of present-day wild populations in other parts of Africa. If the birds had been bred in large farms, the study researchers argue, the ibises would have become less genetically diverse over generations and more susceptible to common diseases—a situation seen today in industrial bird-raising operations.

“The genetic variations did not indicate any pattern of long-term farming similar to chicken farms nowadays,” says Wasef, who adds that if the ibises were indeed corralled into farms, it was only for short periods before being sacrificed and entombed.

But archaeologist Bosch-Puche, who was not a part of the study, believes that the birds were indeed bred in captivity, due to signs of healed fractures and infectious diseases seen in ibis mummies that are similar to those documented in modern captive animal populations that have little genetic diversity. Such injured, sick birds, he says would have been unable to hunt or escape predators in the wild.

Bosch-Puche says that all of Egypt between 650 to 250 B.C. was essentially a “factory” for mummies. “There were even baby animals, who didn’t have time to reach adulthood, [being mummified] as they needed a huge quantity of them,” he adds.

In light of the new findings, he says that wild ibises may have been attracted to the food at existing ibis farms, and that would have made it easier for Egyptians to hunt them in large numbers to supplement their farm-bred animals.

“But we are still talking millions of animals at different sites all over Egypt, so relying just on the hunting of wild ones does not convince me,” he says.

But Aidan Dodson, an honorary professor of Egyptology at Bristol University, says that although the new genetic data goes against traditional ideas about how ancient Egyptians were able to sacrifice and mummify the birds on such a massive scale, this DNA study is the first objective analysis on the subject.

“The idea that ibises were farmed is simply a guess to explain the huge numbers of them, [it’s] not based on any archaeological or documentary evidence,” says Dodson. If Egyptians were not breeding ibises but rather capturing them in the wild, the latter requires a “different social construct” for Egyptologists to consider, he adds.

The new DNA research also may help answer a bigger question of why the African sacred ibis eventually went extinct in Egypt by the mid-19th century. Up until now, researchers have presumed that sacred ibises, who enjoy marshy wetlands, could have disappeared as Egypt’s climate became drier over time, says Wasef.

“Habitat loss cannot be the sole answer, as these birds adapt and turn to human garbage heaps [for food], so why did this happen?” says Salima Ikram, an archaeologist at the American University in Cairo and a co-author of the paper. “This is part of a larger puzzle that deals with human and animal interactions and their impact on the environment.”