The polar regions with bad weather were once dinosaur habitats?

The bipolar environment is the coldest and most difficult environment on the earth today. Most living things cannot live alone in these two areas for a long time. However, the polar regions are not always uninhabitable. There is gradually evidence that a large number of dinosaurs lived in the polar regions during Mesozoic, which sounds incredible, because in our impression, reptiles generally lived in warmer places.

The temperature in the north and south poles is warmer than it is now.

Although the mid-latitude regions of the earth were generally warm in Mesozoic, the temperature in polar regions was relatively cold even without ice sheets. The study of plant fossils and related air isotopes in plate sedimentary rocks can determine the annual average temperature of Mesozoic poles; The results show that the average temperature in the North Pole is about 2-8 degrees Celsius, while the temperature in the South Pole is about 10 degrees Celsius. This temperature is not cold at all, it is much warmer than the temperature in the north and south poles today.

The conjecture that dinosaurs might have lived in polar regions was almost unthinkable fifty years ago, because it was widely speculated that their metabolism was closer to modern reptiles than birds and mammals. The fossils collected by paleontologists in these areas in the past 20 years have gradually changed people's minds.

Definition of polar dinosaurs

Dinosaurs not only occupied the poles 65.438+0.9 billion years ago, but also the remains prove that almost all major dinosaurs lived and evolved there. Interestingly, besides sauropods, there are also "polar" dinosaurs. By paleontologist Thomas? Ricky and Roland. Online dating and dating? Hamm's definition is "a dinosaur who lived in the bipolar circle in the dinosaur era, and now it is not necessarily found in the bipolar circle." This means that their fossils are sometimes found in some originally polar regions, such as Australia, parts of New Zealand in southern Alaska, Russia and Canada in the north.

Discovery of polar dinosaur fossils

Kerviel river bed in the northernmost part of Alaska is one of the places where polar dinosaurs are found most in the world. Signs of polar dinosaurs are usually rare. The most complete polar dinosaur fossil was found in Mata Nukasa River in the center of southern Alaska, which contains almost a quarter of this huge animal. Foot bones, limbs and tail are enough for paleontologist Anna? Patch confirmed that this guy was a member of the hadrosaurs, because they were dinosaurs with mouths like hadrosaurs.

The study of determining the age of fossil sedimentary rocks is relatively simple because of the appearance of benthos, such as ammonites, which can be determined about 900 thousand years ago. This is almost100000 years earlier than the discovery of hadrosaurs in North America, indicating that Alaskan hadrosaurs may be closely related to early Asian hadrosaurs. It is not uncommon to find the remains of land animals in the ocean, although these remains are often stained and incomplete. Patch guessed that the hadrosaur died on the coast of the ancient ocean and drifted into the ocean like a floating corpse. It eventually sank into the sea and was covered with black mud along with shells and other marine life, so they will be found together with the Google fossil of this hadrosaur.

Why are there dinosaur tracks in the polar regions?

Fossil evidence from polar regions shows that most dinosaur populations once lived in these places. In the northern hemisphere, the remains of hadrosaurs, ceratosaurus, sauropods, Ankylosaurus and stegosaurus were found on the northern border of Alaska, Canada and Siberia. In the southern hemisphere, polar dinosaurs are represented by Ankylosaurus, Xiaolong and possibly Ceratosaurus. These relics do not exist alone, but are often found with fossils of other animals near the polar regions, such as crocodiles, amphibians, dragons, birds and small mammals.

The existence of polar dinosaurs is undeniable, which raises questions about their lifestyle, metabolism and thermoregulation. The first of these questions is whether the survival of dinosaurs in cold regions is more positive and powerful evidence of body temperature regulation and metabolism, or whether there is a deeper answer to this puzzle. Australian paleontologists Thomas Rich and Patricia Chicks Rich have made great progress in promoting the knowledge of polar dinosaurs in the southern hemisphere. They speculated that some small dinosaurs might dig holes in the ground to protect themselves from the cold and long winter nights. Another possible guess is that some small dinosaur groups migrated to the Antarctic in the warm season and returned to the equator in the cold period.

Considering the connection structure between Mesozoic continents, scientists' hypothesis is very possible. Some scientists believe that the clue that some dinosaurs can survive in cold climate may be related to the use of feathers to isolate the cold. At least the small theropod dinosaurs that have been discovered may have such a body covering. With the research of scientists, more and more mysteries of dinosaurs living in polar regions will be uncovered, which will help us to know more about these prehistoric animals.