World's most dangerous bird raised by humans 18,000 years ago, study suggests - CNN

However, a new study of more than 1,000 fossilized eggshell fragments, excavated from two rock shelters used by hunter-gatherers in New Guinea, has suggested early humans may have collected the eggs of the large flightless bird before they hatched and then raised the chicks to adulthood.

The team found that most of the eggshells found at the sites were all near maturity.

"What we found was that a large majority of the eggshells were harvested during late stages," Douglass said.

"The eggshells look very late; the pattern is not random."

These late-stage eggshells indicate people living at these two rock shelter sites were harvesting eggs when the cassowary embryos had fully formed limbs, beaks, claws and feathers, the study said.

Consuming eggs with fully formed embryos is considered a delicacy in some parts of the world, but Douglass said the research team's analysis suggested people were hatching the chicks.

"We also looked at burning on the eggshells," Douglass said in the news release.

"There are enough samples of late stage eggshells that do not show burning that we can say they were hatching and not eating them."

Big bird as valuable resource

Less mature eggshells showed more signs of burning -- suggesting that when cassowary eggs were consumed they were cooked and eaten when their contents were primarily liquid.

To successfully hatch and raise cassowary chicks, people would need to know where the nests were, know when the eggs were laid and remove them from the nest just before hatching.