[After rewriting] mice are good partners of humans, what experiments it really is.
For example, the most famous mouse experiment in the last world - Universe 25.
A man named John M. B. Calhoun scientists did a series of experiments on mice, the 25th experiment he did, hence the name Universe 25. It is said that Calhoun pondered for a long time after doing this experiment, and he believed that this experiment somehow predicted the future of mankind. So, what exactly happened to the experiment that year?
Mice are good helpers for experiments
Rat Utopia
The 25th cosmic experiment originated from 8 mice, 4 males and 4 females, all of which were in the year of fighting and could breed. Calhoun's team created a space for the eight rats with unlimited food and water, divided into 16 zones like pizza. At the beginning of the experiment, the rats moved in, had food, drink and houses to live in, and they soon began to breed, and not long after, the 25th universe was full of little mice.
Experimental poster of that year
Soon, the little mice also began to mature and participate in breeding, just as the mice invaded some islands that year, and the mice in the 25th universe showed exponential growth and soon ushered in an outbreak. As far as the eye can see, the No. 25 universe is full of mice, and the space seems to have begun to be crowded. At this time, the mice began to behave differently. Rats are polygamous, and the stronger the male rat, the more females can mate, which means that whoever grabs the food and water supply in universe 25 can take the mountain.
Sure enough, strong male rats occupy the perimeter of the space, which is closest to where food is served. They are surrounded by females. The male rats, who cannot snatch the vantage point, can only be forced to squeeze into the center of space, and there are no female mice around, all male mice huddled together. Over time, the rat population began to stop rising, almost equaling the dead mice with the newborn rats, but the situation changed again.
Females began to attack their children, even biting them to death, and male rats crowded in the center area had same-sex sex. On the 920th day, a major event occurred in the 25th universe, on this day, not a single mouse was born, that is, the rats, stopped giving birth! The life span of mice is short, without the filling of mice, soon the old mice die one after another, and the number of mice declines.
It stands to reason that the death of old rats will free up a certain amount of space, and the number of rats should rise, but the number of rats in Universe 25 has fallen all the way and is moving towards the brink of extinction. At day 1588, scientists discovered that the rat population had undergone irreversible decline, and on day 1780, the last rat died, the experiment ended, and the 25th universe perished. It can be said that the results of the experiment exceeded everyone's predictions.
Strange changes
I believe many people have heard the story of wolves and deer in Yellowstone National Park. The story is that in order to protect the deer in Yellowstone National Park, Roosevelt sent hunters to kill all the wolves in the park. Deer that lost their natural predators multiplied, eventually exceeding the limits of Yellowstone National Park, and eventually the deer herd declined. However, this is still a little different from the tragedy of Universe 25.
Deer in Yellowstone
First of all, the deer in Yellowstone National Park do not have endless food provided by humans, they need to eat the plants in nature themselves. Secondly, these deer are wild, without human intervention, dead deer carcasses are not cleaned up, but left to scavengers and microorganisms in nature. Finally, the deer herd died out because of ecological damage, and the marriage of close relatives seriously led to the degradation of the population.
Universe 25 has no food troubles, and the only obstacle is limited space. Scientists have found that the entire universe 25 is divided into two groups, one is mice that give birth to children and the other is mice that do not give birth to children. In the 25th universe, only the male rats that occupy the most advantageous positions will have a group of wives and concubines, and most of the male rats that fail to compete have no offspring. These single male rats will show a desire to reproduce, and they even courtship without discrimination, but the results are often not good, so they will fight each other.
Later, scientists found that female mice began to appear in single mice. They do not participate in breeding, but stay in some corners, do not fight or scramble, just groom their hair, and basically do not fight back when they encounter other mice bullying them. If male mice forcibly mate with these females, the females will not nurse their children and will abandon them. Discarded mice are eaten by other mice.
The mice fought without mercy
Yes, even if you eat and drink in the 25th universe, mice still cannibalize. The male and female rats who occupy favorable positions are not much better, especially the female rats involved in breeding, their tempers begin to become more and more irritable, and they have killed and eaten their children. Those male rats with wives and concubines, the competition between them is becoming more and more serious, because they do not worry about eating and drinking, and the lifespan of most of the mice has been improved, which has led to an increase in the number of capable male rats, and the competition between them for resources has intensified.
There is competition between mice
It was also their struggle that caused the female rats in the territory to be uneasy, and finally they did something to kill their children. Rats, when they feel threatened, eat their children. In the end, the rats in the entire universe 25 are all violent, they kill each other, and the purpose of killing each other is not for food.
Rats can also kill each other
In fact, in the last period of the 25th universe, space is sufficient again, as long as the rats at this time participate in breeding again, then the population will soon recover. However, the rats at this time all seem to have infertility and are not fertile, so they stay stupidly in the empty universe 25, and do not participate in mating, until the last mouse dies and the universe 25 collapses.
The 25th universe collapsed, but the mouse's mission continued
Think of human society
Calhoun couldn't explain why the last rats in the 25th universe stopped giving birth, even if most of the rats died and vacated their places, it would not help.
Based on 25 cosmic experiments, scientists have come to a more frightening hypothesis, that is, for a population, in a limited space, perhaps the fertility rate will inevitably become lower, and finally the number will decrease. Universe 25 seems to hint at the future of humanity.
Human modern society
If you think about human society, such things are also happening, that is, people no longer have children, and the fertility rate has declined. At first, it was thought that the decline in fertility was due to the rising cost of raising children, and many high-welfare countries introduced various subsidies for childbirth, but the effect was not obvious. The fertility rate has not skyrocketed because of high welfare.
Many countries have seen a decline in birth rates
Many people believe that fertility is linked to the economy, but the more economically developed the region, the lower the fertility rate. The more big the city, the fewer people give birth. In short, every time experts and scholars talk about the decline in fertility, they always find many reasons, but ignore one key reason, that is, people.
Family of 4
Although scientists can't tell the truth exactly about the demise of Universe 25, they give three reasons. The first reason is the limited space, which is also reflected in human beings, that is, the increasing density of urban populations. If you translate to the future, the population density of the earth is increasing. The second reason is that the distribution of resources is uneven, and in the 25th universe, although they do not worry about eating and drinking, the order in which mice in different positions eat food is different. The third reason is that organisms may perceive population decline, so they default to harsh environments and reduce fertility.
Dense population in cities
Scientists believe that the third reason is related to genes, the genetic similarity of the same species is very high, there may be some kind of communication between them, but humans do not know. For example, the extinct northern white rhino, when they still have a few left, humans protect them, do not lack food to eat, and are also far away from harm, but at this time, the northern white rhinos stopped giving birth. When the last male rhino died, only two females remained for the northern white rhino. From this, scientists speculate that the key to detecting that the environment is not suitable for fertility is not the perception of the outside world, but the perception of genes by organisms.
Northern white rhinoceros
The rats in Universe 25, who sense the death of most of their kind, believe that this place is no longer suitable for survival. When animals think that the environment is bad, they will stop procreation, and even if they do, they will not raise it.
