Dinosaurs lived in the Mesozoic Era, between 250 million and 65 million years ago.
If the Mesozoic era was the age of dinosaurs, then the next Cenozoic era was the age of mammals, and the earliest mammals belonged to the single-for-hole order, that is, mammals multiplied by spawning eggs.
Today, there is a great variety of mammals, but only three species of single-hole mammals still exist, one of the most famous of which is the platypus. (ps Another extant species is the echidna)
Platypus is one of the few living fossils in the world, but its discovery history is not very long.
In November 1799, several British zoologists in southern Australia found an animal skin with beaver fur, a beaver-like bald tail and a duck-like mouth.
At first, almost everyone thought it was a "masterpiece" of a big liar, forged with a duck's beak sewn on a small animal skin, and there was no such animal in nature.
After a few years, a well-known Scottish anatomist made a careful observation and study of the hide and concluded that it was not a trick of a liar, but an authentic natural relic.
Later, the living body of this animal was constantly discovered, what should it be called? After much thought, scientists gave it an figurative name, the platypus.
Then there was a new question, what kind of animal does the platypus belong to? Everyone in the European animal kingdom has a different view on this issue.
Why is it so hard to name platypus? Because there are a lot of strange things about platypus.
Judging from the shape of the platypus, it is very strange.
Although its mouth resembles a duck's beak, it is much taller than a duck's beak, and its beak is, covered with a layer of soft and elastic black skin, the skin has some special structure, and the movement of the electric field in the animal's muscles can be felt.
This allows the platypus's mouth to accurately catch small animals hiding in the underwater silt, its mouth has ridges that can bite food or bite, and there are filters on both sides of the jaw that can squeeze out water.
The platypus's nest is very elaborately built, there are several tunnels connected, which are paved with leaves and hay, and its nest generally has two openings, one is through the waterway, the other is through the land, and the opening is cleverly camouflaged.
Covered with grass and watered with rocks, it sleeps in its nest during the day and forages in groups after nightfall.
The platypus spends most of its time in the water, and even mating takes place in the water, and every summer and autumn is its breeding season, laying 1 to 3 eggs at a time.
The embryos in the eggs have been developing in the body for more than 10 days, so once the eggs are released, the mother beast will begin to hatch. When the egg is incubated, its body rolls up, attaches the egg to its chest, and lies in the nest.
After about 10 days, the small beast broke out of the shell, the platypus egg shell is soft, there is a layer of glue on it, and the small beast has a special tooth in the egg shell, when the shell is broken, it all relies on this pair of small teeth, after the shell comes out, it falls off on its own, replaced by ten deciduous teeth, but the deciduous teeth are not yet neat, but they slowly fall off, which is very magical and interesting, will grow the teeth of the beast but will eventually fall off, as if these teeth are only for the purpose of breaking the shell.
It is also interesting that the female beast has no breasts and nipples, only milk flows out of the breast in front of the breast, and after the shell, the body is very small, no hair, the eyes are not open, and it grows up by licking the milk. After four months, they can swim independently outside the cave for food.
The body temperature of the platypus is low, the general body temperature is maintained at 26 ° C ~ 35 ° C, in addition, the body temperature changes with the external environment, but the change is ranged, when the environment remains unchanged at 30 ° C ~ 35 ° C, it will lose the ability to regulate temperature and die, this physiological feature determines that the survival range of the platypus is very narrow.
Paleozoic platypus
Because platypus has many strange characteristics, after about 100 years of debate, biologists finally defined platypus as a mammalian outline, monotreme, and platypus family in the 1980s.
There is only one family and one genus in the world. Today, platypuses are extremely prized animals in the world and a national treasure of Australia, and like China's giant pandas, exports are generally prohibited.
Platypus is a transitional type of evolution from reptiles to mammals, and due to its primitiveness, the more powerful mammals it has evolved around the world have gone extinct, and only the Australian continent, shortly after the advent of the platypus, moved south alone, isolated from other plates, stopped animal communication, stopped animal evolution, and preserved the platypus to this day.