Eggshells Reveal Surprise About Highly Dangerous Bird

Thousands of years before chickens were domesticated, scientists say humans may have tried to domesticate another bird—one that's particularly deadly. The cassowary is regularly called the "world's most dangerous bird" thanks to its dagger-like claws that can grow up to 5 inches long (as the researchers note in a Penn State press release, the flightless bird bears "more resemblance to velociraptors than most domesticated birds"). It lives in the forests of New Guinea and Northern Australia, and the New York Times reports it operates in a "shy and secretive" manner there; not so when it's in captivity.

And yet researchers say what they found while excavating rock shelters in eastern New Guinea suggests the birds many have been being reared by humans as many as 18,000 years ago. The proof was in the eggshells, per their study published Monday in the Proceedings of the National Academy of Science. In the shelters, they found 1,019 fragments of cassowary eggshell, a large majority of which were harvested during late stages (the researchers developed a new method to determine how old a chick embryo was when an egg was harvested).

That led them to conclude the people were either eating late-stage, nearly developed embryo chicks or hatching them. But "we also looked at burning on the eggshells," says lead author Kristina Douglass, and "there are enough samples of late stage eggshells that do not show burning that we can say they were hatching and not eating them." CNN elaborates on what would have needed to happen: Humans would have had to know the location of the nests to remove eggs from them, but the asterisk here is that the birds don't return to the same place to nest each year, which adds some complexity.

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The eggs are laid by females but then incubated by males for a 50-day period. "People may have hunted the male and then collected the eggs. Because males don't leave the nest unattended" they are "more vulnerable to predators," said Douglass. The birds do "imprint" easily, meaning they bond with to the first thing they see upon hatching, but as the Times points out, the danger comes at the adult, not hatchling, stage. (A cassowary killed its Florida owner in 2019.)