Xu Renjie sat on the roof of his luxury RV, nibbling on a freshly cooked tender corn while keeping a close eye on the movements of the two ghost butlers.

After many years of crisscrossing the mall, he has developed a very good habit ---- observing and studying his opponents.

As the supreme commander of the team, Xu Renjie didn't have to charge into battle, but since the first encounter with the zombies, he has been standing on a specially opened observation point on the roof of the RV, constantly observing the zombies' attack methods and attack habits.

In addition to observation, Xu Renjie also specially arranged two blood slaves to follow him, after each battle, he would let these two guys take a meter ruler to the battlefield to measure and measure, sometimes even the corpses of dead zombies have to be checked and measured, and the data is even detailed to the height and weight of the zombies, whether they are male or female, and how old they are.

It can be said that Xu Renjie was the first person to do such a detailed observation and study of zombies, and after such a detailed study, Xu Renjie found that the behavior of zombies is actually very regular:

First of all, about the attack range of zombies, Xu Renjie found after many measurements that zombies do not rely on their eyes to sense the existence of humans, because of the virus, the eyes of zombies are generally a sickly grayish-white, and their eyesight is very seriously reduced, and they can only see objects within one or two meters of their side, and they can find human beings, relying entirely on their sense of smell.

Twenty-five meters, this is the ultimate sensing distance of zombies, when humans enter the range of twenty-five meters around zombies, the strongest zombies can detect the existence of humans for the first time and launch attacks.

Zombies also have strength and weakness? Of course, this is Xu Renjie's second discovery, like humans, the strength of zombies depends on their physical fitness---- the better their physical fitness before death, the stronger they will be after becoming zombies, and their speed and strength are far beyond ordinary people, otherwise they will become correspondingly weaker, and the increase in speed and strength is not particularly obvious.

However, whether they are strong or weak, zombies are zombies, and after losing the ability to think, their behavior is driven by instinct, and the way of behavior is almost identical.

What is the instinct of a zombie?

There is only one, and that is to eat!

Through careful observation, Xu Renjie noticed that when his team stopped to rest, the zombie group outside the vine barrier would become very calm, thousands of zombies gathered together, but there would be no disputes and contradictions, each zombie was dazed and slowly wandering, and some even stood still, while in a daze, while slowly shaking their bodies rhythmically, as if listening to music.

However, in addition to human zombies and animal zombies, there are many uninfected creatures in the city---- fish in the water, most non-predatory birds, and all insects.

For some reason, the zombie virus seems to be unable to invade the water, which causes all aquatic creatures to survive, while insects may have avoided this catastrophe because their body structure is completely different from that of animals, and the zombie virus cannot affect them.

Non-predatory birds are a very unique exception, and a large proportion of them are not infected because the zombie virus is ineffective against them, but because of the unique food chain of the entire bird group.

In terms of feeding habits, birds can be basically divided into two categories---- predatory birds and non-predatory birds, among which the food of non-predatory birds is plants and insects, and the possibility of them actively being infected with the zombie virus is equal to zero.

Of course, it will not be actively infected, it does not mean that it will not be infected, otherwise so many cattle and sheep will not all become zombies, and non-predatory birds will also be infected with zombie viruses by other animals such as predatory birds, bird-eating cats and other organisms, thus becoming zombie birds, but the probability of being infected is far less high than that of cattle and sheep, because they can fly and are usually small.

Flying, making them difficult to catch, and other predatory birds that have become zombies, because they have lost the ability to think, can hardly catch them, even if they are occasionally caught one or two, their smaller size is not enough to eat a few bites, and when they are infected, they are eaten directly into the stomach, and it is difficult to become zombie birds.

Even if a few birds are infected, their original diet is to eat plants and insects, and after becoming a zombie bird, its instinct will drive it to eat insects and plants instead of meat and other birds, so it is difficult to spread within the bird.

The combination of these causes has led to a large number of non-predatory birds---- sparrows, swallows, etc., almost all of which are infected, and their biggest natural predators---- humans, have also become walking dead and can no longer effectively threaten their survival, resulting in a great increase in the number of these birds.

It is these little guys, who are still active in the city, occasionally fly into the zombie group, and the breath of fresh flesh and blood on their bodies will immediately break the calm of the zombie group, causing a crazy commotion, at this time, the zombies who were originally calm and dazed will suddenly become crazy, desperately rushing to these little guys.

And these little guys, it seems, have long been accustomed to this situation, every time at this time, they will fly lightly, land on the telephone pole or street lamp, tilt their heads to watch the zombies' crazy behavior for a while, and then take off into the air and fly away.

Although the bird's behavior was a bit mischievous, it gave Xu Renjie a very good opportunity to observe, and when he found that the only condition that led the zombie behavior was food, he immediately asked the blood soldiers to use fresh meat to tie grenades and throw them when attacking with weapons.

This kind of grenade tied with bloody flesh only needs a little bit to cause zombies to rush to the location of the grenade frantically, which greatly improves the efficiency of killing zombies.

In addition to this grenade, Xu Renjie also asked each blood soldier to carry a piece of bloody fresh meat, and once he fell into the siege of zombies, he would take out the fresh meat and throw it at the zombies.

This kind of bloody flesh has an almost fatal attraction to zombies, and once it is shot, it can attract the attention of all the zombies around the blood soldier and help the blood soldier successfully escape.

In addition to relying on instinct to control actions, Xu Renjie's second discovery is even more exaggerated, because he actually analyzed the zombie's attack routine through observation, and made a set of targeted methods to deal with it.

Through careful observation, Xu Renjie found that although the zombies look terrifying and have amazing speed, the attack method is actually extremely simple, which is nothing more than catching and biting the three-plate axe, and among the three-plate axe, there is actually only one that can really cause fatal damage to humans, that is, ---- bite!

Only when they are bitten by zombies and see blood, normal humans will be infected into zombies, and attacks such as throwing down and grabbing can only make humans feel fearful, and will neither cause infection nor fatal injury.

It can be seen that teeth are the only real lethal weapons of zombies!

And Xu Renjie's observation of zombies has even been detailed to how and where zombies bite!

The first bite is always the neck! And it's the right side of the neck! When biting, you will first open your mouth wide, then lean your head forward and bite up.

This is the first conclusion Xu Renjie reached, this conclusion was discovered after he splashed sheep blood into the zombie group to cause zombies to attack each other, for this conclusion, Xu Renjie let his blood slaves splash at least hundreds of pots of sheep blood out.