Why can't I find early dinosaur eggs? This dome, 68 million years ago, revealed the answer.
Is the owner of this soft-shelled egg a dinosaur?
According to reports, this soft-shelled egg has been treasured by the National Museum of Natural History of Chile since it was discovered. It is about 28 cm long and about 18cm wide. Recently, scientists found in their research that this soft-shelled egg was left by the creatures inside. Fortunately, it was buried in an ancient stratum. Because the Antarctic continent was uninhabited and discovered very late, it was not destroyed.
In time, the owner of this soft-shelled egg was born about 68 million years ago. Judging from the historical evolution of the earth, the earth is at the end of Cretaceous, about 3 million years before the fifth extinction. So many scientists also suspected that this soft-shelled egg might be a dinosaur egg at first.
But in fact, according to archaeological fossil research, all known dinosaur eggs are hard-shell eggs, and judging from the structure and size of this soft-shell egg, its owner is unlikely to be a dinosaur, because on the Antarctic continent 68 million years ago, dinosaurs living on it were "small" and their physical conditions did not allow them to lay such large dinosaur eggs.
Scientists speculate that this dinosaur egg may come from an ancient marine reptile, possibly a lizard or a sea snake. Previously, scientists have discovered an ancient creature called "mosasaurs", which lived in the ocean at the same time as dinosaurs and was very large. More importantly, they also live in the Antarctic region and are egg-laying animals. Therefore, scientists are now more inclined to regard this soft-shelled egg as a kind of heritage called "mosasaurs".
Is this soft-shelled egg the largest in the world?
Scientists said that from the fossils unearthed so far, this soft-shelled egg is the largest soft-shelled egg found so far, ranking second among all known ancient egg fossils. It can be said that its scale is amazing. So, who laid the biggest egg in the world? Could it be dinosaurs? Sorry, dinosaurs are still not on the list. The largest bird egg in the world comes from an extinct animal-elephant bird.
As can be seen from the name, they are very big, just like "elephants". In fact, they are too. According to scientists' research and analysis of fossils, elephant birds are the second largest birds in the world. They live in Madagascar and have lived on the earth for about 90 million years. It was not until17th century that there were elephant birds on the earth, but later with the development of human beings, elephant birds appeared.
Elephant birds are more than 3 meters tall and weigh about half a ton. Although they have the word "bird" in their names, they can't fly. Scientifically speaking, elephants and ostriches should be close relatives. Elephant bird's eggs are all over 30cm in diameter, and an elephant bird's egg can be comparable to the size of 100 ordinary eggs. This shows how big the eggs of elephant birds are.
How big are dinosaur eggs?
After talking about the biggest egg in the world, let's see how big the dinosaur egg is. Before the birth of mankind, dinosaurs were the most numerous animals in the world. They are distributed all over the world and are huge. As an egg-laying animal, naturally, we have the impression that the eggs of dinosaurs will be very large. Is that really the case?
According to the data, the world's first dinosaur egg was found in the Cretaceous stratum in Provence, France in 1859. Up to today, many dinosaur eggs have been found in the world, but their sizes vary greatly. The smallest dinosaur egg is only as big as the duck egg we usually eat, while the largest dinosaur egg can be as big as an elephant egg.
Why are dinosaur eggs of different sizes? This is because dinosaurs are our collective name for an ancient reptile. They contain many kinds and vary greatly in size. For example, some time ago, scientists discovered a dinosaur fossil. Its neck was 7 meters long, but the smallest dinosaur was less than 1 meter long, so naturally it could not lay too many eggs.
How did dinosaurs lay eggs?
Many people may wonder how dinosaurs laid eggs. In fact, for many years, we have always had a misunderstanding about dinosaurs, because in our view, dinosaurs seem to be a group of "imbeciles." After all, they have lived on the earth for 65.438+0.6 billion years, and they are still lower animals.
However, with the excavation of a large number of fossils, scientists also found that dinosaurs were not as "stupid" as we thought. On the contrary, they are very smart. They live in groups. Among them, leaders will be elected and team members will perform their duties. For example, dinosaurs devoted themselves to taking care of dinosaur cubs.
Animals on the earth generally have estrus, and so do dinosaurs. When the breeding season of dinosaurs comes, dinosaurs will first build a hidden and safe "moon nest" for themselves and their young. After laying eggs, the female dinosaurs will stay by until the young dinosaurs hatch, and the male dinosaurs will also "keep watch" around to protect the safety of their families at any time.
When the baby dinosaur is hatched, both the female dinosaur and the male dinosaur will "raise children" for several years, just like we humans raise children until adulthood. After that, the little dinosaurs will become big dinosaurs. They will bid farewell to their parents, leave their homes and start a new life in other places.
Why can't I find early dinosaur eggs?
Dinosaurs appeared on the earth during the Triassic period, but surprisingly, until today, no early dinosaur eggs have been found, that is to say, a large number of dinosaur eggs found so far came from the Cretaceous period and few from the Jurassic period. This problem has been puzzling scientists until the research results of this Antarctic soft-shell egg fossil were put forward. Some scientists speculate that perhaps the early dinosaur eggs were not preserved because they didn't have hard shells.
What does this mean? Simply put, the eggs laid by early dinosaurs were all "soft-shelled eggs", because dinosaurs actually belonged to the category of reptiles, so they should have many similarities with reptiles in the process of spawning and evolution, that is to say, the evolution of dinosaur eggs also changed from soft to hard over time, but because soft-shelled dinosaur eggs have not been discovered, it is impossible to sort out the detailed evolutionary timeline of dinosaur eggs.
However, at present, the conjecture that early dinosaur eggs were "soft shells" is not without progress. In archaeology, scientists have discovered some protoceratops embryo fossils about 65438+ billion years ago. These embryos are not wrapped in eggshells. Is protoceratops a "viviparous"? Obviously, the answer is no, because protoceratops's fossil eggs have been found on the earth, that is to say, 65438+ billion years ago, perhaps protoceratops at that time had not evolved the ability to produce hard-shelled eggs.
Following this line of thinking to explore, many problems have begun to be solved. For example, in Asia and North America, the most common dinosaur fossil is Ceratosaurus, but so far, a Ceratosaurus fossil egg has never been found. Don't ceratosaurus lay eggs? The answer is of course no. From the perspective of soft-shelled eggs, even Ceratosaurus' eggs were destroyed and there was no way to turn them into fossils.
Ceratosaurus appeared in Jurassic 65438+ billion years ago, which is a link between the preceding and the following in the evolution of dinosaurs. It can be said that dinosaur eggs were still soft-shelled, and it was not until the end of evolution that dinosaurs began to produce hard-shelled eggs, which also means that the first dinosaur egg in the world may be soft-shelled. Next, scientists will study the difference between soft-shell eggs and hard-shell eggs in Antarctica, hoping to uncover more answers.
refer to
Agence France-Presse June 18 article "We finally know what the huge" east-west "fossils in Antarctica are"
The newspaper's article on June 20 th, "The study of the world's largest soft-shelled egg came from before the extinction of dinosaurs."