The Croods tells the story of a prehistoric family just trying to survive in a world that is still almost entirely wild. While the family spends most of their time stuck in their cave – at the behest of their patriarch Grug – they make time to go outside in search of food, including the eggs of large birds.
While many of the animals featured in the film are entirely fictional, the egg harvesting and eating behavior of large birds is very real. Our ancestors in Africa have been eating ostrich eggs and using their shells to make art for over 100,000 years. As humanity spread its figurative wings and spread across the globe, this behavior stayed with us even as we left ostriches behind.
When humans first arrived in Australia around 65,000 years ago, they were primed and ready to harvest the biggest eggs they could get their hands on. The evidence left by these early Australian cultures suggests that they were successful, but there has been controversy over the species of birds they harvested. Now a new analysis of proteins found in eggshells tells us they ate the eggs of Genyornis newtoni, the last living species of a group of birds known as the “Demon Ducks of Doom.”
Beatrice Demarchi from the Department of Life Sciences and Systems Biology at the University of Turin and her colleagues performed the protein analysis that led to species identification. Their findings were published in the journal Proceedings of the National Academy of Sciences.
“Genyornis was two meters tall and weighed 200 kilos. We don’t know exactly what he would have looked like as he has been dead for some time and there are few skeletal remains available. It was definitely a flightless bird with some characteristics shared with ostriches, like the big chest and small wings, but it would have looked more like a big goose or a duck,” Demarchi told SYFY WIRE.
Evidence that humans ate these large eggs comes from burnt eggshells found among the remains of ancient cultures. Scientists studying these sites find two different types of eggshells, one of which is from emus and the other which was unknown. Looking at the archaeological record, we find that eggshells began to be burned around the same time people first arrived in Australia. This supports the idea that they cooked and ate them as they had done with other large flightless birds in Africa, India and Eurasia.
The controversy surrounding the origin of mystery eggs stemmed from its unusual characteristics. The shells, compared to ostrich eggs, are relatively thin. This means that the egg itself was probably relatively small. This was not necessarily what was expected of Genyornis.
“Genyornis was a very big bird. If you look at his femur, it’s huge. So, you would expect the egg to be as big and thick as an ostrich, but ostrich eggs are significantly thicker. The whole argument was based on the morphological traits of these eggshells, so the idea came up that maybe it was an egg of an extinct megapode,” Demarchi said.
Specifically, the alternative hypothesis favored the Progura bird, a chicken-like bird that weighed only 5-7 kilograms – a far cry from the truly massive Genyornis. In an effort to settle the matter once and for all, scientists attempted to extract DNA from the shells, but found that they were too old and the environment was too hot for the DNA to survive without. degrade. Instead, they turned to eggshell proteins and compared them to a number of living birds.
“If you compare the proteins of a group of living birds, including megapodes, you can kind of build a tree that’s good at separating the major groups. All ostriches went to one side, all poultry land went another way, and then there’s waterfowl. When we extracted the protein from the eggshell, we found that they were never in the chickens and megapodes group,” said said Demarchi.
The proteins suggest that the eggshells came from a bird closer to modern ducks and geese, supporting Genyornis’ hypothesis. Unfortunately, even before humans arrived in Australia, most demon ducks were dead, and the added pressure of our presence in the region proved too much for Genyornis to handle. They died out around 50,000 years ago. We can’t make omelettes like we used to.