Late Pleistocene humans may have hatched and raised cassowary chicks

Modern day cassowary chick. Credit: Andy Mack
According to an international team, New Guineans may have taken cassowary eggs at maturity as early as 18,000 years ago. They then reared the birds until they reached adulthood.

Kristina Douglass assistant professor of Anthropology, Penn State. "This behavior we are seeing is coming thousands years before domestication. This isn't a small bird, it's a flightless, ornery fowl that can devour you. It is most likely the dwarf variety, which weighs in at 20 kilos (44 lbs).

Today's report in Proceedings of the National Academy of Sciences (Sept. 27), states that the data presented here "may represent the earliest indication of human control of the breeding of an Avian Taxon anywhere in the World, prior to the early domestication of chickens and geese by many millennia."

Cassowaries don't look like chickens. In fact, they are more closely related to velociraptors that most domesticated birds. Researchers report that cassowary chicks are easy to raise and maintain to their adult size. When a bird hatches, it decides its mother is the best thing for him or her to see. If the bird's first glimpse catches sight of a person, it will follow that person wherever they go.

Researchers found that cassowary chicks can still be traded in New Guinea as a commodity.

Eggshells are important

Although eggshells make up a large part of archeological sites, Douglass says that archaeologists rarely study them. Researchers developed a new method for determining the age of a chick embryo when it was laid. This work was published in the Journal of Archaeological Science.

A captive, modern adult cassowary. Credit: Andy Mack

Douglass stated, "I have worked on eggshells from archaeological sites for many years." "I found research on turkey eggshells which showed changes in eggshells throughout the development of the bird that indicated age. This seemed like a good approach.

The 3-dimensional characteristics of the shell's interior determine the age of the eggs/chicks. Researchers used eggs from an ostrich experiment to develop the method to determine eggs' developmental age at the time the shells broke. The Oudtshoorn Research Farm is part of the Western Cape Government of South Africa. They collected three eggs per day for 42 days to test their method. Douglass and her colleagues were also provided with samples of 126 ostrich eggs.

Each egg was taken four times to create a total 504 shell samples. Each sample had a different age. The 3D images were high-resolution and detailed. The researcher then created a statistical analysis of the egg's interior to determine how they looked during incubation. The model was then tested with emu and modern ostrich eggs.

Because the eggsshells contain calcium, the insides of eggshells undergo changes throughout development. During the middle stages of development, pits start to form.

Douglass stated that although it is time-dependent, the process can be a bit more complex. "We used a combination 3D imaging, modeling, and morphological descriptions."

They then looked at legacy shell collections from New GuineaYuku, and Kiowa. The researchers applied their method to more than 1,000 fragments from these 18,000-to 6,000-year-old eggs.

Douglass stated, "We found that the majority of eggshells were harvested in the late stages." Douglass said that the eggshells are very old and not random. They are either eating baluts, or hatching chicks.

Balut is an embryo chick that has not yet reached maturity. It is commonly eaten in Asia as street food.

Original archaeologists did not find any evidence of cassowaries being penned. Only the meaty parts of cassowary bones were found at the sites, suggesting that these were hunted birds who were processed in the wild and then only the best bits were taken home.

Douglass said that they also considered burning eggshells. Douglass stated that there are enough eggshells from late stages that don't show signs of burning to be able to say that they were hatching, but not eating.

In order to successfully raise and hatch cassowary chicks from eggs, one must know the location of the nests and the date they were laid. Douglass claims that humans collected eggs for food in the Pleistocene.

Priyangi Bulaghsinhala, assistant professor of statistics, Tim Tighe (assistant research professor, Materials Research Institute), and Andrew Mack (grants and contract coordinator, Penn State Altoona) also contributed to this project.

Dylan Gaffney (grad student at University of Cambridge), U.K.; Theresa J. Feo (senior science officer, California Council of Science and Technology); and Megan Spitzer (research assistant); Scott Whittaker; manager, scientific imaging; Helen James; research zoologist and curator of bird; and Torben Rick; curator of North American Archaeology all at the Natural Museum of Natural History Smithsonian Institution. Glenn R. Summerhayes is a professor of archaeology at the University of Otago in New Zealand. Zanell Brand is a production scientist at Oudtshoorn Research Farm Elsenburg, Department of Agriculture of the Western Cape Government, South Africa.

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