In numerous animal documentaries, we can see newborn antelopes and wildebeest standing up in a very short time, and newborn baby elephants staggering to toddler. What's more worth mentioning is that the baby monkeys, which are also primates, can cling to the hair of the mother monkey when they are born, and follow the mother monkey to shuttle flexibly through the trees without being thrown off. However, in stark contrast, human babies are often quite fragile when they are born, wrapped tightly in a warm quilt, and it is difficult to even open their eyes. What is the reason for this?
To put it simply, the brain of a human newborn is born before it is fully developed. Compared to other animals, human babies are truly "premature babies".
Preterm birth here is not the concept of "preterm birth" as we understand it on a daily basis. Scientists have speculated that in order to reach a level of maturity similar to that of primate species such as chimpanzee pups, human babies would theoretically need to spend 18 to 21 months in their mother's body. However, the reality is that human babies are mature and born at about 9 months of age.
In the process of human childbirth, only when the diameter of the female pelvic opening is larger than the double parietal diameter of the fetus, the fetal head can smoothly pass through the pelvis and then be delivered smoothly. However, the normal pelvic opening in women is about 10 to 13 centimeters in diameter. If the baby's head circumference is too large, it may lead to problems such as dystocia, which may threaten the life of the mother and the fetus.
However, when the human head matures, it is about 17 centimeters wide, which is significantly more than the maximum extent that a woman's pelvis can expand. As a result, a fully developed head cannot naturally pass through the woman's pelvis for the normal process of childbirth. Being born at a time when the brain is not yet mature is an important choice in the evolution of humans.
Nature's harsh environmental conditions are also a key factor in the difference between the two.
First of all, animal cubs face more severe challenges to the natural environment, and the structure of the food chain is more complex. At the lower levels of the food chain, animals must be born with a certain level of self-protection, such as running fast to escape predators; Moving higher up the food chain, animals need to move quickly to catch their prey and keep them alive.
Secondly, many animals do not take care of all their young equally when they reproduce. In the case of limited food resources, those cubs who are weak and unable to compete for enough food often cannot survive to the moment when they can leave the nest independently, and they die early due to hunger and cold, and are eliminated by the laws of nature.
Finally, it should be noted that the average lifespan of most animals is much lower than that of humans, and they grow several times faster than humans. Therefore, there is indeed a significant difference between animal cubs and human babies in terms of their ability to stand at birth.