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introduction</h1>
The Earth has been 4.6 billion years old since its formation, and in each of these billions of years, there will be extremely powerful rulers in each period. For example, we are more familiar with dinosaurs in the Jurassic era.
Today, although humans are the rulers of modern society, the lions of the steppe, the tigers of the forest, and the sharks in the ocean still occupy a place in the ecosystem to which they belong, and can be described as the "top strong" at the top of the food chain. However, when you think of crocodiles, you may look frightened, but the concept of their ecological status may be a little blurred.
In fact, the crocodile family has been living on Earth for more than 200 million years, and even after the extinction of the dinosaurs, they still exist. Crocodiles usually live in freshwater rivers or swamps, and can be regarded as powerful "predators". But why have they gone through more than 200 million years and have not evolved to the level of hegemony?
Could it be that the crocodile ancestors' fighting genes were too fragile? No, in fact, they are "targeted" by the Earth when they are about to dominate.
<h1 class="pgc-h-arrow-right" data-track="6" > the origin of the crocodile </h1>
The crocodile is a cold-blooded oviparous animal and a very fierce carnivore. Although the name bears the word "fish", it belongs to the reptile and is the oldest reptile on earth.
Speaking of the birth of crocodiles, it may have originated earlier than dinosaurs, but from the existing fossil records, the earliest crocodiles were probably born in the late Triassic, that is, about 200 million years ago, and belonged to the same era as dinosaurs.
It is conceivable that from the Mesozoic To the Cenozoic, and then to the modern Earth, crocodiles have experienced a lot of periods, and they can be regarded as the "elders" of the earth. It is for this reason that crocodiles have been called "one of the oldest living fossils of living organisms on Earth".
<h1 class="pgc-h-arrow-right" data-track="10" > the characteristics of crocodiles </h1>
If you mention crocodiles, you probably have this picture in your mind: they lurk in a hidden state on the edge of a freshwater swamp, their eyes are tightly fixed on the prey drinking water by the river, slowly creeping and moving, and then they wait for the opportunity to open the blood basin full of fangs and "clamp" the prey in an instant.
Indeed, crocodile days grew a picture of eating meat. They are not only covered with hard armor scales, but also have a large mouth covered with fangs.
The crocodile's maximum body length can reach about 15 meters, and the weight is close to 1.5 tons, which is a proper weight, coupled with its particularly thick limbs. At the same time, crocodiles also have a thick and powerful tail, which allows them to better grasp the direction when swimming, and can also become a tool for prey and a weapon when defending against enemies.
<h1 class="pgc-h-arrow-right" data-track="14" > crocodile habits </h1>
Crocodiles are very fond of wet areas, freshwater crocodiles generally inhabit rivers or swamps, while saltwater crocodiles tend to concentrate in warm, moist coastal areas.
Although crocodiles breathe through their lungs, they are very good at diving, and can even lurk underwater for more than 10 hours. That's why we can always see in Animal World that crocodiles always lurk in the water for a long time when they prey, and then jump out to catch their prey.
When preying, they generally drag terrestrial animals into the water to drown, and if they are aquatic animals, crocodiles will throw them on land, leaving their prey to die of lack of oxygen. It can be seen that crocodiles are actually quite intelligent.
We usually use obtuse to describe crocodiles, but in fact crocodiles are quite flexible in both hearing, vision, and body segments.
In addition to jumping out of the water, they can also "clamp" larger foods with their mouths, wrestle them on stones or tree trunks, and break the food before swallowing.
This is because crocodiles, although sharp teeth, are grooved teeth. These teeth can quickly re-grow new teeth after falling out, but cannot be used to bite and chew food. That's why, as we said before, crocodiles will break up the food and swallow it.
It is also because crocodile groove teeth are not easy to chew food, so crocodiles have evolved a very special stomach. They have a lot of stomach acid in their stomachs, and the acidity is very high, which makes the digestive function of crocodiles extremely good. Some people even joke that the crocodile's stomach contains diluted sulfuric acid.
<h1 class="pgc-h-arrow-right" data-track="23" > crocodile family that is "targeted" </h1>
As we said above, the crocodile has a very strong fighting power, so why did it not get the title of "overlord"? This brings us to their evolutionary history and the process of being "targeted".
The Earth's "Great Oxidation Age" 3.5 billion years ago gave birth to the first life, the single-celled organism cyanobacteria in the primordial ocean. These single-celled organisms evolved through continuous evolution, and about 1 billion years ago, invertebrates evolved in the oceans.
When the time came to almost 400 million years ago, vertebrates appeared on the earth, that is, the most primitive fish, and this era was called the "Late Paleozoic".
Of course, the evolution of life never stops. With the passage of time, some fish developed lungs in the body, they can directly obtain oxygen from the air, so they ran to land, gradually evolved into the earliest reptiles, and the era gradually entered the "Permian".
However, due to the more active movement of the earth's crust in the "Permian", the collision between paleo-plates was very violent. The extent of the sea is further reduced and the land extent is further expanded. This is where the Permian-Triassic extinction event emerged, which was a time of mass extinction.
If you want to calculate the rate of species disappearance, 70% of the terrestrial vertebrates on the earth at that time, and 96% of the marine life, disappeared. Moreover, the ecological circle of land and sea has taken millions of years to fully recover.
However, it is also this change that allows terrestrial reptiles to evolve again. Not only did the most primitive mammals begin to appear, but also dinosaurs with the name of "ancient overlords" were born, and the protagonists we talked about this time, crocodiles.
The earliest crocodile order, known as the "pseudo-crocodile". Crocodiles like the Swift Crocodile, the Tearing Frog Crocodile, and the Lowes Crocodile were large and fierce, and at one point they could tear dinosaurs apart without fear.
The late Triassic period was the heyday of the crocodile family, and many species of crocodiles appeared during this period, almost hundreds of species. For example, Lauriet's crocodile family, Poporon family and so on. Not only are they huge, but they are also very powerful, whether it is diving or sprinting on land. The dinosaurs at that time were naturally not their opponents.
However, the good times did not last long, and the heyday of crocodiles did not last long. When they were just about to dominate, the transition from the Triassic to the Jurassic, the mass extinction event happened again.
This "Triassic-Jurassic extinction event" not only led to the disappearance of 20% of the original marine life, but also caused the gradual extinction of large crocodiles.
It has been speculated that the land at that time was not separated by the sea as it is now, but was all connected together. The intense movement of the Earth's crust during this period forced the supercontinent to split, and the movement of the Earth's crust led to the gushing out of magma, which led to the widespread extinction of the species.
This was the first time earth had "targeted" the crocodile family.
The impact of this incident on crocodile reptiles was very serious. Large crocodiles, almost all of which were extinct, left only smaller and more flexible crocodiles. It was also at this time, the Jurassic era came, those smaller crocodiles could not compete with dinosaurs, dinosaurs naturally suppressed the development of crocodiles with overwhelming victory, and became the top predators of this period.
This also leaves most people with the impression that "dinosaurs are ancient overlords".
<h1 class="pgc-h-arrow-right" data-track="41" > developing into the ocean</h1>
Although they were "targeted" by the Earth, the crocodiles did not give up their hope of dominating the Earth. Due to the Jurassic era, almost all crocodiles were dexterous and smaller land animals that could not compete with dinosaurs. So, they managed to go into the water, hoping to grab a place.
One of the offspring of crocodiles began to develop into the ocean, what we now call "sea crocodiles." Unfortunately, the ocean was in a state of domination at that time. Fin dragons, ichthyosaurs, sharks, etc. are scuffling in the ocean. In desperation, the sea crocodiles went to the tamsui estuary to "make a living".
Because crocodiles have a strong bite force, they can prey on turtles that most marine life can't bite, or raid animals that are drinking water at the water's edge. Coupled with the abundance of fish in freshwater wetlands, crocodiles only need to wait for "meat". This also allows them to mix well in the freshwater swamp area. Moreover, this convenient way of hunting, crocodiles have also been used to this day.
Although they are called "sea crocodiles", they do not really enter the ocean, so sea crocodiles have not evolved into real marine life. However, it is worth mentioning that at the beginning of the Cretaceous Period, crocodiles evolved the largest sea crocodile in history, the "King Marchimo crocodile".
Although it is a sea crocodile crocodile, the food of the King Machimo crocodile is not limited to the small fish and shrimp in the sea.
Previously, at a paleontological research institute in Switzerland, researchers found a bite mark on the femur of a whale dragon, which was compared and found to be the tooth mark of the monarch Marchimo crocodile.
You know, the size of the whale dragon is quite large, an adult whale dragon, almost the size can reach 18 meters, and the size of the king Machimo crocodile is almost 9 meters, you can imagine the terrible point of the king Machimo crocodile. Moreover, paleontologists have speculated that the monarch Marchimo crocodile, like modern crocodiles, will adopt a strategy of lurking in the water and waiting for the opportunity to give the prey a fatal blow.
However, there is a big difference between the Marchimo crocodile and the modern crocodile. The limbs of the Macimo crocodile are webbed, a form that allows them to be more adapted to life underwater, and their tails are large and powerful, allowing them to swim quickly and sensitively in the water, and their ability to predate is greatly improved.
But in general, the crocodile's plan to dominate the oceans has not been solved.
<h1 class="pgc-h-arrow-right" data-track="51" > the second time the crocodile family was "targeted" </h1>
The "Cretaceous" era arrived, when the continents were completely separated by the oceans and the Earth became very warm and arid. Not only did the dinosaur population reach its peak, but there were also a lot of small mammals on Earth, as well as giant snakes.
Apparently, crocodiles could no longer take their place on land, but because of the Jurassic era, the crocodiles almost became the rulers of freshwater wetlands. Moreover, crocodiles have undergone continuous evolution, and in this period, "emperor crocodiles" have also been born.
The emperor crocodile is one of the largest crocodiles that has ever lived on Earth, and it is also known as a super giant crocodile, or a muscle crocodile, because the adult emperor crocodile can reach a length of 13 meters, which is comparable to those theropod dinosaurs.
Not only that, the emperor crocodile also has a very sensitive sense of smell, even if they lurk in the water, they can also smell the smell of distant prey, plus they also have a large mouth full of sharp teeth, in the face of those small dinosaurs, the emperor crocodile does not pay any attention to it, and even can make the small dinosaurs into their own meal in minutes.
But the same good times are short-lived, and history seems to be repeating itself.
At the end of the Cretaceous period, there was a "Cretaceous-Paleogene extinction event", which is also often referred to as "asteroid impact on the earth". This extinction event not only completely destroyed non-avian dinosaurs, but also caused about 80% of the species to disappear.
The crocodile family was naturally badly damaged, and almost 50% of the crocodiles were extinct. The surviving crocodiles, most of which are small crocodiles that inhabit freshwater and terrestrial environments, are gone.
This is also the second time that crocodiles have been "targeted" by The Earth.
However, it is worth mentioning that most people know that the Cretaceous-Paleogene extinction event exterminated dinosaurs, which was very serious. But in fact, the Permian-Triassic extinction event we mentioned earlier is the most serious collective extinction event of biological mass extinction in the geological age.
<h1 class="pgc-h-arrow-right" data-track="61" > slowly shattering the overlord's dream </h1>
While mass extinctions have always hit crocodile families hard, fortunately, crocodiles managed to evolve a "Tethys crocodile" that could live in the ocean during the Cretaceous period.
The descendants of the Tethys crocodile evolved through continuous evolution into a crocodile called the "forest crocodile". The forest crocodile is the crocodile that survived the Aforementioned Cretaceous-Paleogene extinction event.
It is speculated that the forest crocodile is likely to be a relatively large crocodile with a body length of 4.8 meters and a weight of more than 400 kilograms.
Their snouts are blunt, the inside of their mouths is covered with teeth, and the bite force is also very strong. The main food is giant turtles and snakes.
The forest crocodile family is one of the few marine reptiles that survived the extinction event at the end of the Cretaceous period, and they gradually became active in the tropical jungle hundreds of years after the extinction of the dinosaurs.
But unfortunately, they survived the mass extinction at the end of the Cretaceous period, and when they were about to become the king of sea climbers, they encountered the Eocene Extreme Heat Event of the Paleocene.
As if deliberately "targeted" by the earth, the crocodile's road to domination is full of bumps.
The Paleocene Eocene Extreme Heat Event was a time when the Earth heated up sharply. During this period, the Earth suddenly developed a high fever, and the world warmed at a very rapid rate. Especially at high latitudes, the average temperature has risen by as much as 7°C.
Although this extreme heat event did not last more than 100,000 years, it still led to the rapid extinction of a large number of species. It was also at this time that the division between the Paleocene and Eocene ecosystems was quietly formed.
This wave of super warming has completely disrupted the global water cycle. This shattered the plan of the forest crocodile to dominate the sea, and also made the road to domination of the land crocodile far away.
Under the heating of the earth, giant pythons such as titan pythons were born, which were enough to swallow crocodiles raw. As a result, the title of overlord naturally fell to the titan python.
However, titan pythons have only existed for about 3 million years, probably because the earth has slowly cooled after extreme heat events, and large pythons such as titan pythons have difficulty surviving when the temperature is below 32 degrees.
After the forest crocodile, a crocodile called the "Sibe crocodile" has risen rapidly. They were quite powerful and became powerful predators on the South American continent at that time, watching the crocodile family finally take the first step to dominate the earth, however, the descendants of dinosaurs" "Frightened Birds" appeared again.
The horrible bird is a large carnivorous bird that not only has very hard leg bones, but also has quite strong muscles, and a flying kick can even break the bones of medium-sized prey. Moreover, the running speed of the frightened bird is quite fast, can reach 97 kilometers per hour, and the explosiveness is particularly strong.
As a result, the bird and the Sibe crocodile fought on the South American continent for more than 50 million years. Unfortunately, the Sibel crocodile lost more than it won, and the overlord only had to give in again.
Moreover, the Sibel crocodiles mainly lived in the warmer tropical regions, and the miocene climate began to become dry and cold, so the Sibel crocodile eventually became extinct at the end of the Miocene in this extremely cold climate.
By this time, the crocodile's dream of hegemony was almost shattered.
<h1 class="pgc-h-arrow-right" data-track="80" > crocodile today </h1>
To this day, we can see that the crocodile family has really experienced a history of ups and downs and extraordinary development. Now, with the crocodiles that exist on Earth, there is a small group of only 23 species.
Most of them live in tropical freshwater and brackish water regions such as Africa and South America, and only the Yangtze crocodile in China and the Mississippi crocodile in North America are distributed in temperate zones. They lurk quietly in the water on weekdays, and occasionally come ashore to bask in the sun and hunt, which can also be regarded as a kind of comfort.
But perhaps, the crocodile has not given up on its ancestors' dream of dominating the earth, and is now accumulating strength in the water and waiting for the right time.