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

Katie Hunt
CNN Digital
Monday, September 27, 2021 


A cassowary can be aggressive, but it "imprints" easily -- it becomes attached to the first thing it sees after hatching. This means it's easy to maintain and raise up to adult size. (Shutterstock via CNN)

The earliest bird reared by humans may have been a cassowary -- often called the world's most dangerous bird because of its long, dagger-like toe.

Territorial, aggressive and often compared to a dinosaur in looks, the bird is a surprising candidate for domestication.

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. New Guinea is a large island north of Australia. The eastern half of the island is Papua New Guinea, while the western half forms part of Indonesia.

"This behaviour that we are seeing is coming thousands of years before domestication of the chicken," said lead study author Kristina Douglass, an assistant professor of anthropology and African studies at Penn State University.

"And this is not some small fowl, it is a huge, ornery, flightless bird that can eviscerate you," she said in a news statement.

The researchers said that while a cassowary can be aggressive (a man in Florida was killed by one in 2019), it "imprints" easily -- it becomes attached to the first thing it sees after hatching. This means it's easy to maintain and raise up to adult size.

Today, the cassowary is New Guinea's largest vertebrate, and its feathers and bones are prized materials for making bodily adornments and ceremonial wear. The bird's meat is considered a delicacy in New Guinea.

There are three species of cassowary, and they are native to parts of northern Queensland, Australia, and New Guinea. Douglass thought our ancient ancestors most likely reared the smallest species, the dwarf cassowary, that weighs around 20 kilograms (44 pounds).

The fossilized eggshells were carbon-dated as part of the study, and their ages ranged from 18,000 to 6,000 years old.

Humans are believed to have first domesticated chickens no earlier than 9,500 years ago.

NOT FOR SNACKING

To reach their conclusions, the researchers first studied the eggshells of living birds, including turkeys, emus and ostriches.

The insides of the eggshells change as the developing chicks get calcium from the eggshell. Using high-resolution 3D images and inspecting the inside of the eggs, the researchers were able to build a model of what the eggs looked like during different stages of incubation.

The scientists tested their model on modern emu and ostrich eggs before applying it to the fossilized eggshell fragments found in New Guinea. 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.

But were humans purposefully collecting these eggs to allow them to hatch or collecting the eggs to eat? It's possible they were doing both, Douglass 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 RESEARCH

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.

"In the highlands today people raise cassowary chicks to adulthood, in order to collect feathers, and consume or trade the birds. It is possible cassowaries were also highly valued in the past, since they are among the largest vertebrate animals on New Guinea. Raising cassowaries from chicks would provide a readily available source of feathers and meat for an animal that is otherwise challenging to hunt in the wild as an adult," she explained via email.

However, there is still much the researchers don't know.

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. This is no easy feat as birds don't nest at the same sites each year. Once a female lays the eggs, male birds take over nest duty and don't leave for 50 days while incubating the eggs.

"People may have hunted the male and then collected the eggs. Because males don't leave the nest unattended they also don't feed much during the incubation period making them more vulnerable to predators," she said.

The research was published in the peer-reviewed scientific journal PNAS on Monday.

Cassowaries May Have Been Domesticated Before Chickens By Brave (Or Foolish) Humans

CASSOWARIES LIVE ON FRUIT RATHER THAN MEAT, BUT THEIR LETHAL CLAWS STILL MAKE THEM MAJOR THREATS TO ANYTHING THEY DON’T LIKE – HUMANS INCLUDED. IMAGE CREDIT: LUCKY VECTORSTUDIO/SHUTTERSTOCK.COM
By Stephen Luntz27 SEP 2021, 20:00


Long before chicken domestication, humans appear to have raised a different bird species – one capable of ripping a person apart with a single raking kick. Cassowaries make birds’ status as the surviving dinosaurs easy to believe, yet according to a new study, these are the beasts humans somehow chose to raise to adulthood. Strange as that decision may seem, it could explain the cassowary’s survival and the fate of New Guinea’s rainforests.

Eggshells deposited at Yuku and Kiowa in the New Guinea Highlands disproportionately appear to have been collected just a few days before they hatched. In Proceedings of the National Academy of Sciences, the team who discovered this pattern explains it (almost in time for world Cassowary Day) as the result of people's aim to raise the hatchlings, not cook the eggs.

The heaviest birds to have inhabited the Earth in recent times – New Zealands’ Moa and Madagascar’s elephant bird – both quickly became extinct shortly after humans arrived on their home islands. Somehow, however, three species of cassowary have survived in New Guinea and Australia, co-inhabiting with humans for tens of thousands of years.

It’s just possible cassowaries’ survival is a result of humans choosing to raise the young to adulthood as the best way to get their meat, rather than hunting wild birds alone. If so, it proved a very beneficial choice for the health of the rainforests in which cassowaries live, allowing them to continue their vital role as spreaders of seeds.

Cassowary chicks may look harmless at this age, but they don't stay that way.

 Image Credit: Andy Mack

The shape and color of cassowary eggs changes as they get close to hatching and the embryos absorb calcium from the shells. Dr Kristina Douglass of Penn State University and co-authors used this fact to study the developmental stages of shells deposited at the two sites 18,000 years ago.

They also noted that while some shells showed signs of having been cooked; "There are enough samples of late stage eggshells that do not show burning that we can say they were hatching and not eating them,” Douglass said in a statement.

Cassowaries live on fruit rather than meat, but their lethal claws still make them major threats to anything they don’t like – humans included. Douglass suspects the dwarf cassowary variety Casuarius bennetti were the ones being raised, rather than the two larger species. Nevertheless, she noted; “This is not some small fowl, it is a huge, ornery, flightless bird that can eviscerate you.”

There are unconfirmed signs of humans forming a symbiosis with rock doves at Gibraltar 67 thousand years ago, but that aside, the work presented here represents the oldest evidence bird farming in human history. "This behavior that we are seeing is coming thousands of years before domestication of the chicken," Douglass said.

Cassowary nests are rare and hard to find. Moreover, the father guards and incubates them until hatching. It would have taken considerable skill to identify the right time to harvest the eggs, and killing the male to get to them would have carried risks. Nevertheless, New Guineans continue to raise cassowaries today, taking advantage of the fact they imprint easily on humans if one is the first to feed them after hatching.