Compared with animals, why do only human cubs cry and are quite fragile?

Theoretically, the crying of babies is different from that of adults. Adults' crying is mostly caused by emotions and thoughts, while babies' crying is caused by physiology.

When the baby is still in the body, he doesn't need to breathe and eat by himself. The mother will deliver the substances that the baby needs to him through the umbilical cord, and once the baby leaves the mother, the way of delivering nutrition through the umbilical cord is interrupted.

So when a baby comes to the outside world, the first thing he needs to do is breathe. Breathing can let outside oxygen enter the body and carry out normal body circulation. During the circulation, the gas will impact the vocal cords, so the baby will make a sound similar to crying.

And considering that babies need a lot of oxygen to enter the body when they are born, almost every baby will cry for a while.

In addition, let's talk about the problem of fragility. In our nature, many animals are born to walk and jump, while human babies seem to be particularly vulnerable. Not only can't walk, but all physiological activities need the protection of adults.

This reason may be related to people walking upright. Modern research generally believes that there is a price for human evolution to walk upright, that is, the pelvis and birth canal have become smaller.

However, the smaller pelvis and birth canal mean that childbirth is becoming more and more difficult, resulting in many people dying during childbirth. In order to minimize this phenomenon, the baby's body should be as small as possible, especially the baby's brain.

But we can't let the baby's brain fully mature, otherwise the baby's head will be bigger, which will increase the difficulty of childbirth, so our body can only choose a compromise plan.

That is, the baby's brain only develops to a certain extent, and then the rest of the baby is compressed as much as possible, resulting in the baby being very fragile at birth and unable to move at all, and it needs to grow up the day after tomorrow to mature. ...

Many people who have seen the animal world know that most animal cubs have the ability to live independently from birth, and some can run and jump even if they can't live independently. However, when human cubs are born, they don't open their eyes, let alone run away and can't even lift their heads. Without the care of their parents, they have little chance of survival. Then why are you so weak as a primate cub?

The reason is that almost all human children are "premature babies" and are born before "maturity". If animals can walk at birth, then humans will have to stay in their mother's womb for at least one more year, so that the born cubs can basically walk.

Then someone may ask, then why can't the human fetal development period be extended to nine months a year? Some animals are pregnant for more than three years. For example, an elephant can walk when it is pregnant for three years.

This problem involves the evolution of human beings. As we all know, human beings walk from the African continent to every corner of the world, just like opening two skill trees. These two skill trees are upright walking and highly developed in intelligence.

Walking upright not only makes people see farther, but also helps to avoid the attack of wild animals. More importantly, they can be engaged in labor by freeing their hands, but it also comes at a price, that is, they need a stronger pelvis and a highly developed intelligence needs a larger brain capacity. The larger the brain capacity, the greater the proportion of the head in the body, and the proportion of the human head in the body far exceeds that of other animals. So generally speaking, if a person's head can pass through the gap, the body can generally pass through it.

Walking upright, the pelvis is harder, intelligence kills everything and the head is bigger, and human beings can only be born through the pelvis. Therefore, if the fetus develops enough to walk in the womb, there will be no chance of being born, because dystocia will occur. Even if it develops to nine months, the dystocia rate of human beings is the highest among animals, which explains why animals are easy to give birth and human beings may lose their lives, because women bear the cost of human evolution.

It is best not to call human newborns "cubs". Strictly speaking, in fact, it is not only human babies who cry, but also fragile. All young lives are fragile. Many small animals have their own crying methods, and the more advanced animals are, the more naive they are in their early life.

There is a saying that human babies are born early, that is, they are more immature at birth. There are at least two main reasons for this: the first one is related to the size of the brain. As we all know, human beings have the most developed brain, which accounts for the largest proportion of all animals. At birth, the baby's head is the widest part As long as the rest of the head comes out during childbirth, it will be easy. After birth, the brain will develop rapidly, and the head circumference will grow from an average of 34 cm at birth to almost 42 cm at the age of one. If the baby is born late, the risk of getting stuck in the head will be too high.

The second reason is that people are animals with the highest degree of socialization, and the process of socialization must be interactive learning in real life, so the baby came face to face with his parents to learn skills very early.

What is the significance of these two understandings discovered by scientific research? Mom and dad must not underestimate the baby. They dare to come with fragile and immature bodies, which shows that they have unlimited trust in you. I believe that my parents can take good care of them and will teach them to develop their minds and skills from birth. Don't live up to your children's trust and expectations!

Compared with other animals, human babies are still born very early. Many turtles can run to the sea almost immediately without their parents after being born on the beach, and giraffe cubs can walk alone within a few hours after being born. Human babies don't learn to walk upright until they are about one year old, but even so, their survival skills have just begun. It takes longer to walk and eat by yourself, and usually depends on parents or caregivers for more than ten years to survive alone.

Childbirth hypothesis

Scientists generally believe that the unusually developed brain and unique upright walking style of human beings will produce contradictory demands. The wide pelvis can carry the baby's brain, while the narrow pelvis can walk or run effectively. This explanation is called obstetric dilemma. In humans, the size of the fetal head is very consistent with the mother's bone birth canal. The compromise between these conflicting needs is that the baby is born earlier, so that the baby is born while the brain is growing in the uterus and cannot pass through the birth canal.

The above picture shows the skull CT scans of hominids (pictured), chimpanzees (left) and modern humans (right) 3 million years ago.

Among all primates, the brain of human newborn is the least developed. The brains of human babies are only 30% of those of adults, while those of chimpanzee babies are 40% of those of adult chimpanzees. The difference in brain size of newborns shows that human babies develop earlier than other primates at birth.

Energy hypothesis of pregnancy and growth

Although the childbirth hypothesis sounds reasonable, scientists' subsequent research shows that regardless of hip circumference, men and women are very similar in terms of exercise cost and efficiency, and the conflict between babies with large brain capacity and walking upright may be only conceptual, not real. Therefore, scientists put forward another hypothesis, the "energy pregnancy-growth hypothesis", to explain why human babies are born earlier, that is, the mother's energy metabolism reaches the limit, thus limiting pregnancy and fetal growth. When the brain and body of the fetus develop in the mother's womb, the demand for energy will increase exponentially. When the mother reaches the energy limit that can supply the fetus, she will give birth. Even after birth, the baby's brain will continue to develop at the speed of the fetus.

Higher intelligence means a longer learning process.

In addition to the early development of human babies at birth, humans also have a highly developed brain, which can manage complex reasoning, communication and socialization, so it takes longer for humans to learn to acquire these abilities, which is also an evolutionary trade-off. In order to integrate into social groups and play a corresponding role in social practice, a human baby must learn more information about interaction and social behavior from his parents. This explains the long way for human babies to go from helpless newborns to children and then to adults, but in the long run, the long-term relative vulnerability of human babies will eventually bring huge cognitive returns.

Compared with animals, only human cubs cry, and the reason why they are quite fragile is that human beings have degenerated!

For example, when a lamb is born, it can stand quickly. However, human babies need at least 10 months to stand after birth, and even some babies need 13 months and 14 months to stand. It can be seen that human beings have degenerated a lot compared with sheep. This may be related to the gradual improvement of people's living environment, the continuous enhancement of their ability to raise their offspring, and the deterioration of their ability.

For example, not all offspring of animals can adapt to the changes in the external environment after birth. Many animals' cubs will also not adapt to the environment, because they are unable to protect these relatively weak cubs, and animals have to abandon them. Although it looks cruel. But it is good for the population, because the bad genes are discarded, and the offspring animals will be stronger and better adapt to the environment. And humans can even take measures such as raising premature babies in incubators, which makes the ability of human cubs to adapt to the environment decline, and finally they can only cry after birth!

Because crying children have milk to eat, crying is very useful for babies, and how to cry is also very important.

Similar to humans, monkeys cry.

Monkeys, orangutans, humans, etc. Belongs to primates. Judging from their names, we know that primates are smart and powerful characters in nature. Originally, there were several large carnivores on land that could threaten the survival of primates, but after hundreds of thousands of years of wits and wits, tigers, lions and leopards were basically found only in zoos and protected areas, and the number of wolves and bears was greatly reduced. Humans even domesticate cats and dogs as pets.

However, cleverness comes at a price. Primate babies have big heads and small bodies, and their self-care ability is weak. They look quite fragile and need the care of their mothers and relatives for a long time. The baby's crying is a useful tool to tell her mother to "come and take care of me".

Human beings are very sensitive to the crying of babies, and crying can bring help and care to babies. Because wild animals are not common now, mosquitoes are the most threatening animals to human beings. The crying of the baby won't attract mosquitoes, but it can remind the mother to drive away mosquitoes.

If the little monkey doesn't stop crying, it will cause trouble. A study on rhesus monkeys by Stuart semple, a scientist at the University of Roehampton in England, shows that a crying monkey is more likely to be beaten by other monkeys. At this time, the mother monkey will redouble her efforts to coax the monkey to stop crying.

For humans, a baby's constant crying may make others feel nervous or even uneasy, but few people really rush to hit the baby, and some kind people even help strangers take care of the baby, which is also the difference between humans and monkeys.

Perhaps it is this difference that leads to a group of monkeys with only dozens or hundreds, who can only live in the Woods, while human beings can develop a metropolis with a population of tens of millions, which can climb mountains, dive into the deep sea and fly to the moon.

Thank you for reading. Welcome to share your concerns.

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First of all, why do human cubs cry and other animals don't?

The crying of human cubs at birth is caused by the change of respiratory function. The fetus can't breathe spontaneously in the uterus and needs to rely on the mother's umbilical cord to provide nutrition and oxygen. The lungs are in a useless state and contract into a ball. When oxygen enters the alveoli after the fetus is born, the lungs gradually change from solid state to soft state, and the lungs become important organs of the respiratory system. When the baby's chest is opened after birth, it can actively absorb oxygen and exhale carbon dioxide. When the exhaled carbon dioxide passes through the throat, the gas impacts the tense vocal cords of the muscles in the throat, and the vibration is the cry of the baby we hear.

Other animals, such as gorilla cubs or dog cubs, don't cry at birth. Many cubs will only make a faint cry when they are born, which is a manifestation of their adaptation to the external environment. It has something to do with animals themselves, because their vocal cords, respiratory system and laryngeal muscles are different from those of humans, but in fact, human cubs are not really crying at birth, just a way to practice breathing.

Why are human cubs so weak compared with other animals?

We found that many animal cubs can walk by themselves after birth, such as elephants, deer and cows. Their cubs have matured in the body, while human cubs are more advanced than these animals and need more development time, but the size of human mothers' uterus is very limited. Therefore, when the fetus develops to a certain extent, it must be produced, which makes the human fetus appear more fragile than other animals at birth. There is nothing wrong with the cubs of human beings and other animals. Animals that can adapt to the environment can finally survive.

It's not just human cubs that cry. In fact, many mammals are born with shrill cries. In this way, when the mother goes out for food, she can be warned of the danger.

Moreover, the law of the development of nature is that the higher the level, the weaker the cubs, the more unable to survive on their own, and the higher the dependence.

For example, chestnuts, our lovely national treasure panda, are so hot as adults, and when they are born, their cubs are only as big as mice, and they will have dystocia! To be honest, I don't know what it's like to have such a small baby.

Panda cubs are born without hair. If their mother doesn't care about them, they will die easily. In fact, mother panda has two babies at a time, so she can only care for the big and abandon the small, because she can't hold two babies at a time. If she doesn't, the baby panda will die of hypothermia. Therefore, the reproductive success rate of wild giant pandas is very low, so this product will be a national treasure and there is no way to raise it at home.

Baby pandas are hot and small when they are born, but their voices are huge, and their screams will never be lower than those of human babies. The same is to tell mom that you are hugging too tightly, and the baby is suffocating! Or am I hungry? I am so cold!

This is the natural law of biological evolution. Mammals have fewer babies at a time and need better care from their mothers. Usually a few nipples are at most a few babies.

And insects, fish and other low-level creatures disperse thousands of offspring at a time, and there are always awesome ones who can survive. Reptiles don't care when they are born. Birds need to hatch, so it's much harder. Not to mention mammals.

So human mothers are very hard!

I am Yijun, welcome to pay attention to me!

Have you ever seen the animal world? You can often see a large group of zebras followed by lions and leopards. Some zebras are born while walking. If a newborn zebra can't stand up by itself, its mother can't run with it. Moreover, the newborn baby has the smell of blood, which stimulates the hunter to get close to him. If it's fragile, it won't live for an hour.

It's not just human cubs that cry. Many animals in the animal kingdom have feelings. Newborn kittens meow when they are hungry. Of course, this is not crying, but it can't make a human cry. Birds are fragile when they are born and need their parents to take turns looking for food. Birds are very lively when they eat, because if they don't try to open their mouths, they can't eat food. After all, there are always several birds in a nest.

In short, the "strength" of animal cubs is forced by survival.

A: There is a common phenomenon in the biological world, that is, animals at the top of the food chain are generally fragile at birth; Animals at the bottom or middle of the food chain, after their cubs are born, generally have certain action ability, even completely independent ability.

Such as humans, eagles, cats, tigers, lions and so on. At the top of the food chain, their larvae are very fragile at birth and cannot be separated from the care and protection of their parents.

Like wildebeest, snake, chicken, duck, turtle, fish and so on. Their cubs have a certain mobility after birth, and some even have the ability to survive independently.

The reason is not difficult to guess: because there are fewer natural enemies at the top of the food chain, adult individuals have enough ability to protect the safety of their cubs; Creatures at the bottom or middle of the food chain are threatened by natural enemies themselves, and it may be difficult to protect themselves at any time. If the cubs have no certain mobility, the reproductive risk of this species will greatly increase.

However, the above factors alone are not enough. There must be another factor, that is, "in the absence of natural enemies, species evolution will choose young to leave the mother as soon as possible." After adding this factor, the problem can be completely explained.

As for the deep mechanism of the latter factor, biologists have not explained it clearly and can only make some guesses.

For example, Albert speculated that it may be that after the larvae leave the mother as soon as possible, the risk of the mother during pregnancy can be reduced, thus reducing the reproductive cost of the species and increasing the competitiveness of the species.