Dinosaurs lived in the Mesozoic Era, which was between 250 million years ago and 65 million years ago.
If the Mesozoic Era is the age of dinosaurs , then the next Cenozoic Era is the era of mammals. The earliest mammals belong to Monotremes , that is, mammals reproduce by laying eggs .
Today, there are many types of mammals, but only three species of monotreme mammals still exist, one of the most famous is the platypus . (ps Another existing species is the echidna)
The platypus is one of the few living fossils in the world, but its discovery history is not long.
In November 1799, several British zoologists found a hide in southern Australia, with beaver hair, a bald tail like a beaver, and a mouth like a duck.
At first, almost everyone thought that this was a "masterpiece" of a big liar. It was a fake with a duck's bill sewn on the skin of a small animal. There is no such animal in nature.
A few years later, a well-known Scottish anatomy expert carefully observed and studied the animal skin and concluded that it was not a liar's trick but an authentic natural relic.
Later, living bodies of this animal were constantly discovered. What should we call it? After repeated thinking, scientists gave it an -image name, , platypus.
Then there was a new question, which animal does the platypus belong to? Is an animal with a beak, a bird with an animal body, or a hairy reptile ? Everyone in the European animal world has a different opinion on this issue.
Why is it so difficult to name the platypus ? Because there are a lot of strange things about the platypus.
Judging from the appearance of the platypus, it is very strange. Its body is like an animal, and its whole body is covered with hair. The hair is dense short hair, streamlined, and about 50 cm long. Its mouth is an extension of the jaw, which looks like a duck's. Mouth .
Although its mouth is like a duck's bill , it is much taller than a duck's bill. Its mouth is horny , covered with a layer of soft and elastic black skin. The skin has some special structure , which can Feel the movement of electric fields in animal muscles .
This allows the platypus's mouth to accurately capture small animals hidden in the underwater mud. Its mouth has ridges to bite or crush food, and there are filters on both sides of the lower jaw to squeeze out water. .
The platypus's nest is very elaborately built. There are several tunnels connected to , which are covered with leaves and hay. Its nest generally has two openings, one leading to the waterway and the other to the land. The opening is very cleverly disguised as . .
Those with access to land are covered with grass, and those with access to water are covered with rocks. They sleep in the nest during the day, and go into the water in groups to look for food when night falls.
The platypus spends most of its time in the water, and even mating is carried out in the water. has its breeding period every summer and autumn, laying 1 to 3 eggs each time. The embryo in the
egg has been developing in the body for more than 10 days, so once the egg is discharged, the female animal will begin to hatch. When incubating eggs, its body rolls up, holds the eggs against its chest, and lies in the nest.
About 10 days later, the little beast broke out of the egg. The platypus' egg shell is soft with a layer of glue on it. The little beast has a special tooth in the egg shell. It relies on these two small teeth to break the egg. Teeth, automatically after hatching fall off, replaced by ten deciduous teeth , but the deciduous teeth have not grown neatly , but slowly fall off . This is very magical and interesting. Animal teeth will grow but eventually fall out, as if these teeth are just In order to break the shell of and come out with .
Something else interesting is that female animals do not have breasts and nipples, only milk flows out from the breasts in front of the breasts. After hatching, the body is very small, has no hair, and cannot open its eyes. It relies entirely on licking milk to grow. big. After four months, they can swim independently outside the cave to find food.
The platypus has a low body temperature. The general body temperature is maintained at 26℃~35℃. In addition, the body temperature changes with the external environment, but the change has a range. When the environment remains unchanged at 30℃~35℃, it will Losing the ability to regulate temperature and dying, this physiological characteristic determines that the platypus's survival range is very narrow.
Paleozoic platypus
Because the platypus has many strange characteristics, after about 100 years of debate, biologists finally defined the platypus in the 1980s as mammal outline , monotremes and platypus .
There is only one family and one genus in the world. Today, the platypus is an extremely rare animal in the world and a national treasure of Australia. Just like the giant panda in China, its export is usually prohibited.
The platypus is a transitional type that evolved from reptiles to mammals. Due to its primitive nature, it evolved more powerful mammals around the world and became extinct. Only the Australian continent moved southward alone shortly after the emergence of the platypus. , isolate from other sections, stop animal exchange , stop animal evolution , so that the platypus can be preserved to this day.
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