Ancient Egyptians Sacrificed and Mummified Millions of These Sacred Birds—Here's How They Gathered so Many

The ancient catacombs of Egypt contain millions of mummified birds of the species Threskiornis aethiopicus—better known as the African sacred ibis. Now researchers have cast new light on how the Egyptians obtained so many of these animals—something that has long puzzled experts.

The Egyptians commonly sacrificed and mummified these birds between 665 B.C. and 250 A.D. in honor of the god Toth—who was often depicted as a man with the head of an ibis.

A small number of ibises lived in temples and were worshipped as real-life incarnations of Toth—the god of justice, wisdom, magic and the moon. The birds were subsequently mummified after their natural death.

Ibises that were sacrificed before being mummified have been found stacked floor-to-ceiling along miles of catacombs at major historical sites in Egypt. But researchers have lacked evidence providing clues to how the Egyptians gathered such a staggering number of ibises.

Some historical texts indicate that the Egyptians may have bred these birds on an industrial scale in dedicated, long-term facilities located next to, or within, temple complexes. In fact, one piece of writing from the priest and scribe Hor of Sebennytos—who lived during the second century B.C.—discusses how he regularly fed thousands of sacred ibises with "clover and bread."

In order to investigate how the Egyptians obtained birds for sacrifice and mummification, a team led by Sally Wasef from Griffith University in Australia analyzed the genomes—the complete set of genes present in a cell or organism—of 14 sacred ibis mummies, dating to around 2,500 years ago. They also did the same for 26 modern specimens found in the wild across Africa and then compared the two datasets.

The researchers say that if the Egyptians were domesticating and farming the ibises over long periods, you would expect there to be low genetic diversity in the ancient mummified birds due to inbreeding. However, they found that the mummified birds displayed just as much genetic diversity as the modern wild ibises.

According to the team, this indicates that rather than obtaining them from an industrialized and centralized farming system, the Egyptians likely relied on short-term taming strategies among wild populations, according to a study published in the journal PLOS ONE. For example, priests may have tamed the birds in their natural habitat or possibly farmed them only at certain times of the year to meet the demand of annual rituals.

Ancient Egypt, Toth
Scene from the Books of the Dead (The Egyptian Museum) showing the ibis-headed God Thoth recording the result of the final judgment Wasef et al, 2019

"Surprisingly, and in spite of the millions of mummies found, no signs of long-term inbreeding were found inside the ibis DNA," Sally Wasef, lead author of the study from Griffith University in Australia, told Newsweek. "Most likely, that suggests that the priests tamed wild populations through food temptations within their natural habitats, such as the lakes or wetlands close the temples."

"This study sheds light on a ritual practiced over quite some time by the ancient Egyptians and how priests obtained millions of the sacred ibis birds to be sacrificed annually," she said.

Sacred ibises were not the only animals that the Egyptians mummified (although they are by far the most numerous). Researchers have discovered all manner of mummified creatures in historical sites across the country.

"The list is really long, you can name most of the animals and birds known to ancient Egyptians as getting mummified at one stage," Wasef said. "Some were pets and in the same time gods like cats, dogs, falcons, monkeys. Some were just god's incarnations on earth like snakes, crocodiles, cows, etc."

The largest known number of sacred ibises can be found at the Tuna el-Gebel necropolis in Middle Egypt, which houses roughly four million of these mummies.