Whenever sharks are mentioned, most people subconsciously think of their "childhood shadow" great white sharks. The bloodthirsty and brutal jaws in the movie left an indelible impression on many people. But what everyone doesn't know is that sharks have actually experienced all the way to "crawling and rolling" to climb to today's position.
Stills from Jaws
The lament of shark evolution belongs to the existence of "the listener is sad, and the hearer is in tears". Because this guy appeared 400 million years ago, not only experienced many mass extinction events, but also been bullied by other overlords for hundreds of millions of years. The kind of bitter feeling that is very depressed and has been doing "the second of the ten thousand years" is not understood by humans who are already at the top of the food chain.
The evolution of sharks
Sharks are actually very old creatures that have been on earth for more than 400 million years. The oldest sharks are called slit sharks, which lived mainly during the Devonian and Carboniferous periods and are only about one meter long.
Slit shark
This ancient shark is not much different from the current shark in terms of size and appearance. However, its jaw joints are not as strong as the sharks are now, and its teeth have more sharp edges. The reason why I chose to evolve in this way is because the dry rice standard of the ocean in that period was "no smashing your mouth", and simply put, dry rice had to be "swallowed raw".
In our opinion, the schizoty shark performed very well at that time, but the boss of the ocean at that time, Dunn's fish, was too fierce, whether it was 8 to 10 meters in length or weight of 4 tons, it ruthlessly crushed the schizoph shark. And the main hunting target of Dunn's fish is invertebrates without "hard shell armor", so the rift shark should be a very favorite dish.
Dunn's fish and slit shark
The sharks that dared to fight and think chose to evolve and become pectoral spine sharks with iron-shaped dorsal fins on their backs. And because it was pressed to the ground by the Dunn's fish and rubbed for too long, the pectoral shark decided to fight in another place.
So it came to the shallow water area near the shore, originally with its physique in this can be "dimensionality reduction strike", did not expect the emergence of Thesis root tooth fish offshore, this guy body length of more than three meters, weight of more than 1 ton. In this way, the entrepreneurial dream of the pectoral shark was shattered just at the beginning.
The unlucky "thoracoagranon shark" who was violently beaten by the Heath's root-toothed fish
However, these marine creatures suffered a mass extinction event together in the late Devonian period, and a new generation of sharks also decided to evolve in a different way.
Geological epoch stratification
This time, they learned the lessons of the past and realized that they were too small because they were "small", so the primary goal was to grow bigger, and then they evolved a stronger fighting force, "armed to the teeth". The spiny tooth shark is 7.5 meters to 15 meters long, and the teeth look like the gears of a cutting machine, which is puzzling.
This shark, which lived in the Late Permian, did roam the ocean for a while, but it didn't take long for the Permian mass extinction to come. The spiny tooth shark became extinct in the process, and the shark family began to think about how to innovate.
"Armed to the teeth" of the spiny tooth shark
It may be that after passing the overlord, it feels a little boring, and the bow shark has made its body smaller again, only maintaining the shark's linear posture.
Although the Buddhist bow shark did not mix much better in the sea, it evolved its teeth into two kinds, the pointed ones used to eat smooth ones, and the flat ones were used to eat shells, and they survived very comfortably in the shallow waters of various seas.
It is worth mentioning that the shark chose to reduce its size to live in peace, which should also see the situation of the seabed at that time. At that time, there were all kinds of ichthyosaurs in the ocean, one more powerful than the other, making the entire competition stage like a "fairy fight". Therefore, the bow shark chose to lie directly flat, did not participate in the inner roll, and was happy for a while.
There's also a "food chain" in the ocean.
Forced to "evolve"
But sometimes you think about Buddhism, but the world forces you to "roll inside." Therefore, in the middle and late Cretaceous period, the appearance of Hoffman's dragon almost destroyed the shark's vein. This guy is the top predator of the Mesozoic ocean, with a body length of more than 17 meters and a weight of 16 tons, I believe many people are impressed by the dragon in the movie "Jurassic World".
The dragon in the movie
When the shark was forced to the end of the road, it decided to "give it a fight, the bicycle becomes a motorcycle". Chalky stingray sharks appear at this stage, they are also called golden kitchen sharks, with a body length of about 7.5 meters and sharp teeth. After this guy grew up like this, he dared to attack the dragon, of course, mainly against the smaller dragon. Larger, they sometimes resort to siege tactics.
In short, although the chalky shark of this period could not rank first in the ocean and was crushed by the dragon, it also performed very well. However, as the dragon grows bigger and bigger, the chalk shark is at an absolute disadvantage again, and it can only be said that life is not easy.
The chalky shark that besieges the dragon
Fortunately, another great reshuffle of the earth has arrived, and the Cretaceous mass extinction has made a series of creatures such as the dragon withdraw from the stage of history. Although the chalky stingray shark has also become extinct, some small sharks have become "lucky", and after witnessing the previous fairy fights, they firmly chose the "bigger and stronger" strategy and made their body very large.
The Chubutkek shark in the family Porphyllum during this period was about 14 meters long and had teeth up to 129 mm long.
Chubutker shark
Although it looks big enough, the sharks are really trying to compete for the first place this time. Also, looking back at his own evolutionary history, he was often bullied by other overlords for hundreds of millions of years, and he encountered a biological mass extinction event for a while. Therefore, adhering to the belief that "reinvigorating the glory of sharks, my generation is indispensable", the megalodon appeared.
This shark, which many biologists have praised as the largest fish and the strongest predator in history, finally made the shark raise its eyebrows. It is reported that the megalodon is about 18 meters long and weighs 70 tons, of course, because there is no complete fossil, this value may fluctuate, because some scientists believe that this giant beast has at least 20 meters.
Megalodon and Great White Shark
Megalodons lived from the Late Miocene to the Early Pleistocene and preferred to prey on whales. It also ushered in its rival in the ocean, the Melville Whale, which was more than 17 meters long and weighed about 65 tons, and was considered the only marine creature that could compete with the megalodon shark at that time.
According to the available evidence, Melville whales and megalodons fought for about 1 million years and eventually withdrew from the battlefield somehow. Since then, megalodons have ushered in their own "fish peak" and dominated the ocean for many years.
Melville Whale
But in the end, it still could not escape the influence of the environment, and in the case of food shortages, the huge megalodon shark began to "hunger and fullness", and eventually became extinct.
Maritime overlords are also immune to sanctions
Nowadays, the fearsome great white shark, although very strong, is still not invincible in the ocean, such as killer whales and other "ocean street skaters" like to bully great white sharks.
Overall, the evolution of sharks is really tough. But they are very good at following the trend, and they can escape extinction and suppression every time, which is also a unique skill of sharks. In addition, today's sharks also have some special abilities, which is probably the "wisdom achievement" of hundreds of millions of years of evolution!
Great white sharks that were violently beaten by killer whales
Shark's unique abilities
First of all, sharks have "supersensitive ability", and they have amazing perception of electrical signals, light, etc. All this proves that sharks' "sensory abilities" are very rich, whether it is touch, taste or smell, which makes their marine life more exciting.
Secondly, sharks will deliberately remember their good experiences, such as eating "a big meal" somewhere in the ocean today, and sharks will often revisit the same place, trying to eat that delicious food again. The "dry rice sharks" represented by tiger sharks are not in the minority in the ocean.
The "tiger shark" who is cooking
In the end, the shark still inherited the indomitable will and adventurous spirit of his ancestors. When we mentioned the Golden Kitchen Shark vs. The Dragon in the previous article, it was said that they were forced to roll in and then evolve. Today's sharks are not as reckless as they once were, but they still like to challenge the impossible and take risks.
Studies have shown that some species of gill sharks dive 250 meters deep to enjoy the animal bodies that researchers have thrown onto the ocean floor. In order to obtain food, these sharks will bravely enter the death zone, where oxygen content is extremely low, and the possibility of serious consequences of suffocation is high, but they have no choice but to pay attention to food.
Six-gill sharks foraging on the ocean floor
It can be seen that the shark's awareness of dry food is indeed very strong. Perhaps these sharks who were fed, after eating and drinking enough, went back to write a "Peach Blossom Origin" to praise the "two-legged beast" of human beings.