1, whale shark and megalodon shark
As we all know, the largest surviving fish is whale shark, which can grow to 20 meters long and weigh more than ten tons. It is also the longest cartilaginous fish in history, and the more famous prehistoric giant fish is Megalodon. Although it is not as long as whale shark, its weight is three to four times that of whale shark, and it should be the largest cartilaginous fish in terms of weight.
2. Leeds fish
The above two kinds of fish are cartilaginous, and the other prehistoric bony giant fish is Leeds, which can reach 27 meters in length and weighs about the same as Megalodon. There are some controversies about the length of Leeds, and some studies believe that it is about the same length as whale sharks.
The existing ancient giant fish are actually similar to paleontological fish. Although they have not evolved to be bigger or smaller after so many years, of course, some extinct ancient giant fish are indeed bigger than the existing ones.
Their extinction is probably caused by mammals occupying the ecological chain, because mammals in general are smarter, evolve faster, the environment is changing, and they are constantly adapting.
3. Coconut crab
Coconut crab is a terrestrial arthropod, the longest of which is one meter long and weighs more than 6000 grams. Compared with terrestrial arthropods in Carboniferous period, it is not enough to see, because Carboniferous period was the golden age of terrestrial arthropods, because centipedes were more than one meter long in Carboniferous period, even dragonflies were as long as their arms.
Why is Carboniferous the golden age of terrestrial arthropods? It is mainly caused by the high oxygen content of the earth. At that time, the oxygen content of the earth was about twice as high as it is now, while the respiratory organs of arthropods have strong ability to absorb oxygen and can effectively promote the growth of somatic cells, so they are relatively large.
4. Amphibians: giant salamander, serratula przewalskii and crocodile salamander.
Hunan Province once captured a giant salamander, with a body length of 1.2 m and a weight of 300 kg. The giant salamander belongs to amphibians, but compared with prehistoric amphibians, it is still inferior, because the sawtooth salamander is 9 meters long and weighs as much as 3 tons, and it is much bigger than the crocodile salamander, which is also an amphibian.
Only later, amphibians became smaller and smaller. If I guess correctly, they can't compete with reptiles in the ecological chain, such as crocodiles, turtles or seals.
5, fragile double-cavity dragon
What impressed us most was the dinosaurs of Jurassic and Cretaceous. In terms of body shape, the largest dinosaur belongs to fragile double-chambered dragon. According to its fossils, we can know that it has a long neck, a small head and a slender tail. Strangely, its nostrils grew on the top of its head, and it lived at the end of Jurassic.
Whether the fragile double-chambered dragon is the largest dinosaur is quite controversial. Some people think it is the Swiss Pultalon, while others think it is the Argentine dragon. Because of the controversy, the length and weight are not listed.
There are many other prehistoric giants, so I won't list them here. So let's think about it, what factors affect the growth size of animals?
First, the respiratory system.
The greater the weight, the greater the amount of oxygen needed. If the respiratory system is very efficient, it will promote the growth of the body. As we all know, the golden age of arthropods was the Carboniferous period. At that time, the earth was full of oxygen. Because the respiratory system of arthropods was not yet evolved and perfected, and the oxygen absorption efficiency was high, it grew greatly.
Second, the energy acquisition efficiency is high.
The development of the body needs the maintenance of energy. The bigger the individual, the more energy he needs, because the bigger the individual, the more energy he consumes in exercise, so he needs more food.
In the Mesozoic era, the natural environment was superior and ferns grew wildly, so the dinosaurs had high foraging efficiency, did not need to run around, did not need to consume too much energy, and the food was abundant, so the dinosaurs at that time were very big.
Third, the breeding methods are different.
Mammals are different from reptiles in that one is viviparous and the other is oviparous. In the Mesozoic era, due to the better environment and abundant resources, the reproductive efficiency of oviparous eggs was higher. In the Cenozoic era, the environment became worse, the resources were not as much as before, and the survival rate of viviparous was higher. Therefore, in the later period, viviparous animals occupied a dominant position.