After Lu Yuan left the swamp, he continued to travel west.

On the third day, he again encountered a tributary of the Amazon River.

There are so many tributaries of the Amazon River that Lu Yuan can't figure out what the name of this tributary is.

However, the water of this river is very clear. In the middle of the river, a herd of hippos was found in the distance.

This discovery shocked Lu Yuan, and he couldn't help but rub his eyes and suspect that he had seen it wrong!

Lu Yuan has always been interested in all kinds of wild animals. He also knew some basic information about hippos.

The hippopotamus is the largest omnivorous freshwater species in the mammals and artiodactyls. It is the third largest mammal on land after elephants and rhinos.

The body length is generally 3.5-4.5 meters, the tail length is about 56 cm, and the weight is 3000-3500 kg.

However, hippos are relatively short, generally only 140-165 cm tall at the shoulders, have a particularly large mouth, larger than the mouth of any animal on land, and can open at a 90-degree angle.

The hippopotamus has a thick and round body, short limbs, 4 toes on its feet, a huge head, small eyes, ears and tail, huge lower canine teeth, thick skin, and bare skin on the whole body except for sparse hairs on the snout, tail and ears.

It mainly lives in tropical aquatic areas of Africa, and often consists of more than 10 individuals, and sometimes can form large groups of hundreds of individuals.

Solitary hippos are mostly adult males who have been expelled from the herd, and spend almost all of their time in water during the day, eating aquatic plants and eating more than 100 kilograms per day.

When aquatic weeds are scarce, they come ashore at night to feed on plants or crops.

They are afraid of cold and warm, and can sneak along the bottom of the river for 5-10 minutes, and during the mating season, there are fights between males.

Hippos are creatures that have been on earth for a long time.

Their ancestors walked the earth 55 million years ago.

For a long time, people associated hippos with pigs, believing that they were close relatives.

But it wasn't until 1985 that there was no evidence that hippos had nothing to do with pigs.

Evolutionary scientists now believe that hippos share the same ancestor as cetaceans.

Their ancestors formed two separate clades of evolution 54 million years ago.

One branch eventually evolved into whales and dolphins.

Another branch gradually evolved into Carboniferous.

One of the Carboniferous tribes eventually evolved into a hippopotamus.

Judging from the fossils found by archaeologists now, hippos first appeared in the Kunlun region.

The latest research suggests that hippos once spread across Eurasia, but have become extinct in most areas due to human activity.

The reason why Lu Yuan was very shocked was because external information showed that there was no hippopotamus in the Americas.

Although it has been mentioned in the diaries of some explorers that there are hippos in the Amazon, it has not been recognized by the scientific community.

Similarly, adventurers from the western countries of the 17th century once recorded the discovery of a 46-meter-long python in the Amazon.

There are also crocodiles up to 15 meters long, but these have also been unrecognized by the scientific community.

Scientists believe that this is contrary to the theory of evolution, and that the evolution of life on Earth should be a gradual reduction in the size of the body.

Moreover, with the current environment of the earth, it is impossible to have the behemoth of the prehistoric period.

However, there is still a small group of people who do not agree with this theory, and they have tried to prove it many times.

But many of the expeditions organized by these people have never returned after going deep into the Amazon jungle, and the occasional ones that have returned have not yielded much gain.

I didn't expect that a hippopotamus group really appeared in front of me now, how could this not shock Lu Yuan.

Lu Yuan tried to get closer to observe the group of hippos.

Suddenly, he noticed that something in the water seemed to be approaching the hippopotamus.

When I looked closely, it turned out to be a caiman. Seeing the caiman, Lu Yuan stopped instead.

The caiman quietly approached the hippopotamus herd, and under the sudden attack, successfully killed a hippopotamus cub.

Just when Lu Yuan thought that the matter was over.

Suddenly, a male hippopotamus several laps larger than an ordinary hippopotamus became in trouble, roared, and suddenly launched an attack on the caiman not far away, pouring out and biting the caiman fiercely.

The caiman was clearly unprepared and was bitten squarely.

In Lu Yuan's surprised gaze, the caiman was actually bitten in two by the hippopotamus.

This result was completely out of Lu Yuan's expectations, although from the information of the hippopotamus, the hippopotamus has an amazing bite force, but I never expected that it could reach the level of biting an adult caiman.

Could it be that the hippopotamus here has also mutated?

Curious, Lu Yuan quickly searched for various information about the hippopotamus.

It turns out that the hippopotamus is actually a highly dangerous animal, and its temper is very short-tempered.

In particular, male hippos often attack a variety of animals, and unlike other beasts.

Other beasts of prey attack other animals mainly for prey, and rarely take the initiative to attack other animals.

The hippopotamus is completely different, it attacks other animals, and in most cases has nothing to do with food.

In the area where the hippopotamus lives, there are also frequent incidents of hippos actively attacking humans.

Every year, many people die in the mouth of hippos.

Not only that, hippos, an irrational animal, are also very particular about territorial power, and even within the same hippopotamus herd, crazy fights often occur.

Every year, a number of baby hippos die in the chaos caused by adult hippos fighting.

After the adult hippopotamus bit the caiman, Lu Yuan took out the camera and prepared to continue observing the hippopotamus.

He wanted to find out what was different from the hippos in the Amazon.

Just then, his camera suddenly caught a strange creature.

Lu Yuan's spirit was shocked, and he found that it was a large fish with a body length of about 8 or 9 meters.

It looks very fierce on the outside, its body is extremely strong, its head and neck are covered with a heavy, hard exoskeleton, its back is darker, and its abdomen is covered and temporarily invisible.

At this moment, the strange fish suddenly jumped out of the water and hit the hippopotamus in one bite

The hippopotamus is like a papier-mâché paste, and it is easily bitten into pieces.

"Is this, Deng's fish?" Lu Yuan exclaimed in his heart.

The shape of this fish looks very much like the legendary Dun's fish.

"How can there be a Dunkle fish here, it's a creature from the Silurian and Devonian eras!"

Dun's fish, a representative member of the family Dinosauridae, is the largest known member of the shield fish family, surviving between 360 million and 415 million years ago.

It was the absolute overlord of the Silurian and Devonian seas. Of all known organisms on Earth, the Dunkle has the largest bite force.

Sharks have long been regarded as the most ferocious animals in the ocean. But compared to the dunkle's fish, it is completely inadequate.

The bite force of an adult shark is only about 1 tonal.

However, the bite force of the dunkle fish is as high as 5 tons, and it is the most powerful creature ever discovered.

The shark comes up to it and it can tear it in half in one bite!

At the time of the survival of the Dunkle fish, it was definitely at the top of the food chain of the ocean at that time, and could prey on any kind of life in the Devonian ocean.

It may well be the first creature on Earth to rule the oceans.

It existed 175 million years before the birth of the first dinosaur on land.

Although the dun's fish is powerful, its huge body and size greatly affect the speed and sensitivity of the dun's fish.

As a result, it gradually lost to small sharks and other carnivorous fish in the process of evolution.

Coupled with the changes in the earth's environment, it eventually gradually left the arena of biological reproduction and evolution.

Lu Yuan was puzzled in his heart, how could the dungeon's fish, which should have been extinct a long time ago, still survive here, and this is a freshwater river, but the dun's fish is a marine creature.

"Could it be that this is an evolutionary product of the Dunkle's fish?"

Lu Yuan thought for a moment and then temporarily gave up observing the hippopotamus.

Instead, this "Dun's fish" was tracked and observed.

After a period of observation, Lu Yuan thought that this fish should be an evolved Dun's fish.

Based on observations over this time, its bite force should be less than 3 tons, but it is still far stronger than that of a shark.

Corresponding to the decline in bite force, it is noticeably much faster than its ancestors, and it is no wonder that it was able to survive.

Maybe it shouldn't be called "Dun's fish" anymore!"

Lu Yuan smiled and put away the camera. I'll leave it to biologists to discuss these issues.

Lu Yuan felt that after he went back, he would send these materials to Zhuxia's biologists for research.

......

Leaving the living quarters of the Dunkle Fish, Lu Yuan continued to advance towards the legendary Kara Empire.

On this day, Lu Yuan was photographing a strange plant, and suddenly heard the sound of countless animals running.

Lu Yuan was stunned for a moment, and quickly straightened his waist.

In a few moments, countless animals rushed past him in panic. It seems that some catastrophe is coming.

Half an hour later, a scene appeared in front of Lu Yuan's eyes that made his whole body numb.

Thousands of ants, like well-trained soldiers, formed a powerful army of ants, swept in like a tide.

"Marching Ants!"

Marching ants are also known as legionnaires, don't look at their small size. But they are the real apex predators of the Amazon jungle.

They differ from other ants in that they gather together to form aggressive groups.

The aggressor group will walk on land and attack its prey. Marching ants usually form a large army to hunt.

As soon as they encounter their prey, they will tear it apart with their jaws, eat it nearby, and then continue hunting elsewhere.

While searching for prey, the larger marching ants will stand near the marching ant army to protect the army.

When marching ants hunt their prey en masse, they set out in dense and regular columns, while some marching ants march in broad horizontal formations.

As soon as they leave the camp, they branch out and branch out, outflanking and besieging their prey! All molluscs and slow-moving insects become their mouths.

Once the marching ants are dispatched, they are like a raging tide, and any animal that stands in their way will be torn apart by them.

They are the true predators of the Amazon rainforest, true super-predators.

Even crocodiles, forest worms, jaguars, and other beasts at the top of the food chain can only flee in a hurry when faced with marching ants.