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| Humans may start raising raptors as early as 18,000 years ago |
A study in the United States shows that the history of human breeding of birds of prey can be traced back to 18,000 to 6,000 years ago
.
According to a report by CNN on the 28th, researchers at Pennsylvania State University in the United States have analyzed more than 1,000 fossil cassowary egg shell fragments and came to the above conclusion
.
These eggshells were unearthed from two stone houses where ancient humans lived on the island of New Guinea, north of Australia.
Christina Douglas, who led the research, said that they found that humans’ history of raising cassowary birds of prey was "thousands of years earlier" than raising chickens
.
Because poultry chicks absorb calcium in the eggshell during their growth in the eggshell, scientists can determine the incubation stage of the eggshell by detecting the calcium content in the eggshell
.
Studies have shown that most of the cassowary egg shells in the stone house are at the end of incubation, close to the stage when the chicks are almost mature and about to break out of their shells
.
Eggshells that are in the immature incubation stage are often burnt
Researchers speculate that the ancient humans living in the stone house would cook some crane ostrich eggs when they had not yet formed chicks and were still liquid inside, while leaving other crane ostrich eggs until the chicks broke out of their shells, and then began to raise them.
When they grow up, they use their feathers as decorations and feed on their meat
.
Douglas said that adult cassowaries are highly aggressive and difficult to hunt and use.
It is easier for humans to raise them when they are young
.
After the female cassowary lays its eggs, the male cassowary is responsible for incubation, during which time it will not leave the egg for 50 days
.
They eat less during the incubation period, their combat effectiveness is reduced, and they are easy to hunt
The cassowary, also known as the "cassowary", is tall and is the third largest bird in the world after the ostrich and emu.
It is good at running and jumping, but its wings are degraded and cannot fly
.
Its innermost toe has a toenail that is more than 10 centimeters long and sharp like a dagger.
The cassowaries are divided into two types: double hanging cassowary, single hanging cassowary and pygmy cassowary
.
Researchers say that ancient humans may have raised the smallest pygmy cassowary, which can still weigh up to 20 kilograms
The research report was published on the 27th of this month in the monthly journal Proceedings of the National Academy of Sciences
.
(Ou Sa) (Xinhua News Agency special feature)Academy of Sciences
