When did the fear of birds die out?

It is generally believed that the Moyamoya people began to die out around 1500, although it has been reported that until 18 or even 19 century, the Moyamoya people still lived in a remote corner of New Zealand.

Although some people think that the number of Moyamoya began to decrease before the arrival of human beings, the extinction of Moyamoya was mainly attributed to the hunting and forest reclamation of the ancestors of Maori Polynesia. Before the arrival of human beings, the main predator of fear birds was the Harvestian eagle, one of the largest eagles in the world, which is now extinct. The kiwi was once considered as a close relative of the moa, but after DNA comparison, it was found that the moa was actually closer to the emu and turkey eater in Australia.

There are other reasons for the extinction of the fear bird.

People are quite familiar with and concerned about the extinction of dinosaurs. Another equally extinct animal, also associated with the word "giant", looks strange. This animal is called "fear of birds". The fear bird is a wingless bird that lived in New Zealand a long time ago. In the past, people always thought that the extinction of the largest bird known to mankind was the result of indiscriminate killing, but scientists now find that the responsibility for the extinction of this bird is not entirely on human beings.

The story of fear of birds usually unfolds like a legend. A long time ago, this big bird like an ostrich lived happily in a land with white clouds. Maori people call this land "Otiloa", which is now New Zealand. About 7000 years ago, an influential day came, and the first humans came there. They are Polynesians. It is said that they came from Hawaii by canoe and found a wingless bird on New Zealand Island, which is easy to kill and can provide them with nutritious food. This kind of bird is a fear bird. Adult moas are 3.5 meters tall and weigh 250 kilograms. Meat is delicious. Within a few centuries, Maori killed all these unfortunate feathered behemoths.

Just like the dodo, the fear of birds has since become a symbol of human greed, or in modern terms, a prominent example of unsustainable development. But is this really the case? Scientists have raised great doubts about this statement through molecular testing, that is, should Maori be so blamed for this disastrous consequence?

In fact, before humans arrived in New Zealand, the number of fear birds began to drop sharply. Even before humans threw the first spear, the fear of birds was a local vulnerable group and was very vulnerable to external attacks. There are 10 species of fear birds, and the biggest one is fear birds. A team of biologists led by Neil Gimel, a biologist at the University of Canterbury in New Zealand, extracted DNA from the largest preserved dinosaur skeleton, and then obtained the DNA sequence through a computer model based on mutation. As a result of population mixing, mutations occur in each generation. By examining these tiny genetic changes, scientists can turn back the molecular clock to see how a species evolved, and they can also infer the number of this population: the larger the number, the more extensive the genetic changes.

After carefully studying the data of birds' fear, Gimel's team deduced the number of such birds, which they called "low to alert level". 1000 years ago, millions of dinosaurs lived in New Zealand. The researchers said that with the addition of nine other species of fear birds, about 3 million to 1 0.20 million fear birds lived on the islands in northern and southern New Zealand from10,000 to 6,000 years ago. When humans first arrived there around 1280, the number of fear birds was less than 159000.

Why did the number of fear birds drop so much before the arrival of mankind? Gimel put forward several novel theories, one of which is that the number of fear birds has decreased due to volcanic eruption. He believes that climate change is not the reason for the decline in the number of fear birds because there is no convincing evidence for this view. Volcanoes often erupt around lake taupo, the center of New Zealand's North Island, destroying the local fear bird living area again and again.

However, there is a more convincing explanation that the sharp decline in the number of fear birds is caused by the spread of diseases, such as bird flu, salmonella or tuberculosis, which are brought there by migratory birds from Australia and other places. Of course, if humans don't reach that place, the number of moyamoya can rebound. Because the arrival of human beings destroyed their living environment and killed moyamoya, their number was further reduced.

Gimel's research results were published in academic journals published by the British Academy of Sciences. According to the research report, the reasons for the extinction of the fear bird are very complicated and have been buried with the passage of time. The article said: "If our new estimate of the number of fear birds is correct, then we need to reconsider the factors that affected the number of fear birds before the arrival of humans. Maybe we can better understand and solve the problem of modern environmental protection by summing up the lessons of the past. "

The moa used to be the largest bird in New Zealand, with an average height of 3 meters, which is higher than today's ostriches. The fear birds are all yellow and black except the yellow feathers on the abdomen. Although the upper limbs of moa have degenerated like ostriches, its body is big and its lower limbs are short, so its running ability is far less than that of ostriches. The biggest difference between a moa and an ostrich is that its neck is covered with feathers, while an ostrich's neck is bare and longer than a moa's neck. It has three toes, and an ostrich has two toes.

"Monogamy" in Bird Camp means that survivors can live together for life or die in one of them until they find another spouse. They live in pairs all the year round in the primitive lowlands and coastal forest grasslands of the southern islands of New Zealand, feeding on berries, grass seeds and tree roots, and sometimes eating some insects. Because the moa is huge and needs a lot of food, each pair of moa has its own large territory. Because the land is vast and sparsely populated, the food is abundant, and there are no natural enemies, only a few aborigines hunt, but the original hunting methods of aborigines have not caused a fatal blow to this group of aborigines. Therefore, until the beginning of the18th century, there were still many moas living comfortably here.

/kloc-in the middle of the 0/8th century, European immigrants came to the island, which brought bad luck to the moa. I'm afraid poultry meat is a delicacy for European immigrants. Because fear birds don't know how to hide, Europeans can easily catch them and often kill more than a dozen at a time. Fear bird meat has become an important source of meat for these European immigrants. At the same time, due to the arrival of European immigrants and the increasing number of local aborigines, a large-scale burning and reclamation began, and the habitat of the fear bird was completely destroyed, and the fear bird was starved to death in large numbers because it lost its foothold. At the same time, for fear that birds would destroy crops, they killed a large number of fear birds to protect crops. Domestic dogs and mice that came to the island with Europeans have also become natural enemies of the fear of birds. They also give a fatal blow to the fear birds.

By the end of18th century, the number of fear birds was very small, and it became more and more difficult for people to catch fear birds, and 1800 was the last year when people could catch fear birds.

For the disappearance of bird fear, human beings are undoubtedly the culprit. But I'm afraid it's unfair to put all this account on the head. The reasons for the rapid disappearance of the fear birds are more complicated.

Scientists' simulation experiments on the dynamic changes of the number of fear birds show that the mortality rate of adult fear birds was high at that time, while the birth rate was very low. The high mortality rate may be related to the natural enemy (human being is the protagonist) killing this unsuspecting animal at will. Natural disasters (such as volcanic eruptions) are also one of the reasons.

As for the low birth rate, it can be explained that the reproduction rate of giant animals is very low, but correspondingly, their life span is very long (mice, insects and other small animals have high reproduction rates, but they are short-lived ghosts). On an island with limited area and food, there is no restriction of natural enemies, and the high reproduction rate is very unfavorable to the survival of this huge animal, the fear bird. There must be a mechanism in the genes of the fear birds to limit the "population expansion", otherwise they will destroy themselves because of excessive reproduction and eating up the edible plants on the island. It is said that the fear bird only lays one egg at a time.

However, if there were no foreign invasion in those years, the low reproduction rate of the fear birds would not constitute an extinction crisis.

find

Although Maori aborigines told European immigrants that this giant bird once roamed the plains and valleys, early Europeans found no evidence that this giant bird ever existed.

1839, John W. Harris, a linen merchant in beaufort Bay, was interested in natural history. He noticed an unusual bone found on the river bank given to him by the Maori. He showed this bone about15cm long to his uncle, John Ruhr, a surgeon in Sydney, and then the bone was sent to richard owen who works in the Huntrian Museum of the Royal College of Surgeons in London. Owen studied this bone fragment for almost four years, and finally he thought it was the femur of a large animal, but the bone was unreasonably light and had many small holes like a honeycomb.

Owen announced to the skeletal world and the whole world that this is the skeleton of a giant extinct bird similar to an ostrich and named it "dinosaur fossil". His inference was once laughed at, but later the discovery of fossils proved his correctness.

Although many species were published at the end of 19 and the beginning of the 20th century, most of them are based on some unearthed fossils, which are synonymous. In the latest research, according to the DNA recovered from the museum collection, it is considered that there are actually only 10 species, including 2 species of giant fear birds. Giant fear birds seem to be hermaphroditic, and females are much older than males; Because the size varies greatly, it is divided into two different categories. Giant fear birds can grow to 13 feet and become extinct earlier, about 1300 years.