This question really confuses many people. It took 150 million years from the rise of dinosaurs in the Jurassic to the Cretaceous. This period of time is about 150 times longer than the time that humans have experienced since the birth of humans. But the information obtained from the fossils is that the huge dinosaurs had only a small brain, basically the size of a golf ball. Why didn't it take so long for dinosaurs to evolve more complex brains? Did dinosaurs have really small brains?

Indeed, dinosaur brains are generally much smaller than those of mammals with the same head size. Compared with the human skull, where most of the bone surface is brain matter, the largest proportion of the dinosaur skull is its jaw structure. Most of the available space in the skull is occupied by powerful biting muscles, and the brain is buried in the thick The shell of the skull is well protected.

The system used to roughly estimate the intelligence of dinosaurs (and other creatures) is called the encephalization quotient (abbreviated as EQ, which can be shortened to brain quotient, although emotional intelligence also has the same abbreviation, maybe there is some connection, haha) . Developed by American paleontologist Harry Jellison in the 1970s, a dinosaur's brain quotient is the ratio of its brain weight to the brain weight of a "typical" animal of similar weight. Warm-blooded mammals and birds generally have higher brain quotient ratings than cold-blooded reptiles of the same size, and there are large differences in brain quotient estimates among different species of dinosaurs, which may be attributed to their different lifestyles and metabolic rate.

Above: Comparison of the injection molded brain of Vineyardosaurus and the size of a walnut. It looks a little larger than a walnut.

Most dinosaurs had brain IQs similar to those of modern reptiles. Usually herbivorous dinosaurs such as large sauropods, ankylosaurs and stegosaurus are at the lowest end of the brain scale. It's often said that the brain of Stegosaurus was about the size of a walnut - in fact it was closer to that of a lemur or a dog, but it was still a bit too small for a dinosaur that was 9 meters long. Later ornithischian plant-eating dinosaurs of the Cretaceous period, such as Edmontosaurus, had slightly larger brains, but were still small relative to carnivorous dinosaurs.

Predatory theropods are thought to have had relatively large brains and excellent eyesight because they needed speed to hunt prey. For example, Tyrannosaurus rex had an exceptionally large brain, even compared to other predatory dinosaurs of a similar size.

However, at the top of the brain scale are those theropods most closely related to modern birds, small and medium-sized carnivorous dromaeosaurs like Velociraptor, and dinosaurs like Troodon Such a troodontoid dinosaur.

Troodon's brain was comparable in size to the brains of today's flightless birds, such as ostriches, and they had large eyes, which pointed to binocular three-dimensional vision. Additionally, they helped locate prey. of keen hearing.

Pictured above: Compared with modern animals (cats, dogs) and humans, the brain quotients of various dinosaurs are extremely weak.

Therefore, the brains of dinosaurs are not all the legendary "walnut" size. Their brain capacity is related to the type of dinosaur. Generally speaking, the brains of carnivorous dinosaurs are larger than those of herbivorous dinosaurs. To be larger, some dinosaurs of the late Cretaceous period had brains that developed to the top of dinosaurs. In other words, after more than 100 million years of development, the brains of dinosaurs have finally evolved to the level of intelligence of today's ostriches - but this still cannot be called the evolution of "wisdom." Why didn't dinosaurs develop larger brains and higher intelligence like humans?

Regarding this issue, there are probably several theories:

Some researchers believe that human evolution is a low-probability event, which is largely due to the "development of the brain" "The cost" is high. Nerve cells require more oxygen than body cells because they send chemical and electrical signals along their long, thin nerve fibers. Brain cells consume 20 times more calories than muscle, and for most species, having 20 pounds of extra muscle is more beneficial than adding a pound of brain matter.

When dinosaurs first appeared in the early Mesozoic Era (an era about 250 million years ago), the Earth's atmospheric oxygen content was too low to adequately supply the brain--intelligence requires enough energy, and energy requires oxygen. For life on land, high oxygen is an important survival and development condition.

Above: A dinosaur’s brain was tiny compared to its head. The survival advantages of dinosaurs are stronger jaw muscles and larger bodies. They grew larger because of their survival advantages. A species smaller than its body size would be less likely to devote energy to brain development. Given intelligence, large size may actually be a disadvantage.

One possible counterexample is the giant octopus, which is touted by some as having extraordinary intelligence. But in fact, the evolution of octopus intelligence is seriously affected by the oxygen supply in the water.

If they have huge brains, they may encounter the problem of insufficient oxygen supply in the water (especially the deep sea), unless they change their circulatory system (such as changing to breathing on the surface), but this evolution is too Radicalization seems unlikely.

In addition, Earth's average carbon dioxide levels were higher from the Jurassic to Cretaceous, which was a major reason for the mild climate from the Jurassic to Cretaceous. Higher levels of carbon dioxide suppress neural activity, making larger brains more susceptible to "toxic paralysis" due to high levels of carbonic acid in the blood (nerve cells are more sensitive to the pH of body fluids than body cells). Of course, this is just speculation because there are no living dinosaurs for scientists to study the physiological activity of their brains.

Above: Mesozoic carbon dioxide levels were much higher than today (nearly 3000ppm), while modern times do not exceed 1000ppm. This is the fundamental reason why dinosaurs have abundant food, and the higher toxicity of carbon dioxide is also a possible reason why dinosaurs' brains are difficult to develop.

Longstanding evolutionary theory holds that intelligence actually arises from some kind of environmental pressure.

For humans, climate fluctuations in East Africa were caused by the formation of the East African Rift System (which probably occurred about 20 million years ago), thousands of kilometers of crustal upheaval stretching from present-day Mozambique to Deep cracks in the Earth's crust in Lebanon, and the continuous climate changes brought about by this geological change, may have prompted emerging primates to develop the intelligence to effectively predict and analyze the continuously changing environment, thereby coping with long-term food shortages. This can show that "adaptability" is the most powerful driving force for intellectual development. Moreover, some scholars even believe that the evolution of human intelligence to such a high degree is actually due to some kind of "accident". The direction of evolution in response to the above-mentioned so-called environmental pressure does not necessarily point to intelligence, so human intelligence is still somewhat "lucky" factors.

Even so, some researchers speculate that if humans disappear, some species of crows or parrots (which are avian dinosaurs themselves) may evolve and take our place. In the eyes of some researchers, the intelligence of African gray parrots is impressive, such as their ability to use their beaks and claws to purposefully use objects. They evolved intelligence for the same reason we did, because they were trying to survive in a forest landscape that was constantly changing due to rapid climate change - these parrots had to be able to imagine where food would come from in two weeks' time, and they needed to be able to predict the future. .

For dinosaurs, the selective pressure of the environment in which dinosaurs lived was not conducive to the development of an overly energy-consuming brain.

Environmental change is a major selective pressure. Environmental changes take many forms, including food supply, climate change, reproductive competition, etc. The more than 100 million years from the Jurassic to the Cretaceous was a relatively long period of mild climate on the earth. There were no dramatic large-scale climate changes (except for the one at the end of the Cretaceous). The main producers on the earth were plants. Extraordinarily lush, which makes it very easy for herbivorous dinosaurs to obtain food, so high-cost wisdom does not seem so "necessary". In addition, the brains of tall sauropod dinosaurs also have blood supply problems, which also limits their brains from further "growing".

Like all reptiles, dinosaurs lacked a neocortex. The neocortex is a brain structure unique to mammalian brains. Its evolution and development have enabled mammals to have more complex social behaviors.

Currently, we do not know enough about the brain to definitively state that the neocortex is a structure necessary for intelligence. Especially because birds, the surviving branch of the dinosaurs, also show many signs of intelligence (without a neocortex) and have developed many brain functions that are often similar to mammalian neocortex lobes. But clearly, all the "smartest" animals are large mammals, and there does exist a close relationship between the relative size of the neocortex and intelligence. For example, the human neocortex makes up more than 90% of our cerebral cortex. One hypothesis is that the intelligence of birds (dinosaurs) may have developed on a parallel track to mammalian intelligence, but due to a different structure from the mammalian neocortex.

Above: Comparison of the brain structure of modern reptiles, birds and mammals, and humans.

Summary

Evolutionary pressure does seem to be the primary reason why dinosaurs did not evolve intelligence, and human beings’ “luck” lies in being chosen by the hand of God in the right place at the right time. We have been striding forward towards the bright road of higher intelligent species till today. Perhaps the neocortical structure of the mammalian brain can be regarded as a starting point for the development of intelligence, but it should not be the only "starting point". The level of intelligence of some birds seems to indicate that the brain may also become more and more "increasing" along other evolutionary paths. Tired of harm".

Millions of years are just an episode in the history of life, and dinosaurs have never left. Maybe after the "little noise" of human civilization disappears (most likely to fend for itself), the dinosaur family will become serious. The earth "sits right" on the throne of intelligent species. Hundreds of millions of years from now, the ones studying human fossils may be dinosaurs! Today you think you are stupid, but tomorrow you may be laughing at you for being stupid! hehe.

Well, theoretically speaking, there is a certain degree of chance for human beings to produce civilization. First of all, we know one thing, that is, the human species has not been born for a long time. Human beings originated about 5 million years ago. At this stage of time, how long did dinosaurs exist? The answer is about 160 million years.

So from the perspective of species existence alone, humans are far behind dinosaurs, but one thing needs to be understood. Dinosaurs are not an animal. They are a general term for many prehistoric reptiles. Simply put, dinosaurs are not an animal. It is said to be a general term for a class of animals just like mammals today.

Then the reason why dinosaurs did not produce civilization is both accidental and inevitable. The accidental nature is easy to understand. It is said that a huge meteorite ended the rule of dinosaurs and caused the demise of the entire dinosaur family. Since the dinosaurs are all dead, The evolution of civilization came to an abrupt end.

But without that meteorite, everything would be hard to say. Maybe if the dinosaurs were given enough time, one of them might be able to evolve civilization. , and we modern people don’t know whether dinosaurs evolved intelligence, so unpredictable meteorites may be one of the reasons why dinosaurs did not develop civilization.

Secondly, there may be a certain inevitability that dinosaurs did not produce civilization. In fact, the time from the birth of human beings to the emergence of civilization was very short. In just a few million years, the human species ushered in a qualitative change. leap.

Well, as I said above, the entire dinosaur family has existed for 160 million years. It stands to reason that if civilization is to arise, it should have arisen long ago, so there should be some reason that restricts the dinosaurs from being able to Like humans, evolve in a more advanced direction.

I personally think that the reason may have something to do with the ecological niche occupied by dinosaurs. As we all know, the dinosaur family is extremely powerful. They were the most powerful dinosaurs on earth from the Triassic to the Cretaceous. The rulers were almost the same as today's humans, and being powerful meant being at the top of the food chain.

When a species is at the top of the food chain, it has no natural enemies. Without natural enemies, there is no pressure, and without pressure, there is no need to change. When dinosaurs can easily use their powerful bodies to hunt prey. , there is no need to evolve a smarter brain, and a smart brain is precisely the key to evolving civilization. Therefore, the reason why dinosaurs did not evolve civilization may be related to the ecological niche they occupied.

Finally, let’s talk about humans. Humans are a branch of mammals. Mammals are said to have existed during the dinosaur period, but mammals at that time were very miserable and often became Food for dinosaurs, so when humans appeared, the situation was very miserable. At that time, part of the forest was gone, and human ancestors had to come to the ground from the trees.

But there is not so much food on the ground, and there are many wild animals. In order to fill their stomachs, human ancestors had to join groups for warmth and then live cooperatively. In order to withstand the impact of the natural environment, humans must find ways to survive. Down the line, in this process, the human brain gradually developed and became smarter and smarter. But ultimately, the initial reasons were all forced. If human ancestors were as powerful as dinosaurs, I guess There is no human species now... Human beings have an evolutionary history of 3.5 billion years and are the only species that have created technological civilization.

The human species is not two million years old, only about two hundred thousand years. However, the DNA inheritance in human beings is far more than two million years, and is at least 3.5 billion years. If time is accumulated, any existing species will be longer than the extinct dinosaurs, and among all existing species Among them, only humans have created technological civilization. Note that it is technological civilization.

Nature has no leap - Darwin

The foundation of civilization is culture. Nowadays, zoologists have observed that many group animals also have their own culture. Although it is very weak, it meets the definition of culture. , for example, certain monkey groups, chimpanzee tribes and even killer whale groups have their own unique culture, which can be regarded as the prototype of civilization. Chimpanzees and even some corvids can make and use tools. Although the technical content of these tools is still too low, it at least proves one thing. The evolution of life on earth to this day has reached the point where the birth of culture and civilization has come to an end. Just like if enough people buy lottery tickets, someone will always win, and humans are such a winning species.

In order to prove that I am not just talking nonsense, I still have to provide some solid scientific research, rather than anecdotes.

In July 2017, the Proceedings of the National Academy of Sciences (PNAS) issued a special issue "Biology through Culture", which published a series of research on animal culture by scientists from the University of St. Andrews and behavioral new papers. The finding that various cultural traditions are widespread among animals means our work on how culture evolves requires broader research and understanding, the study concluded. Human beings are of course the leaders in cultural expansion. As early as tens of thousands of years ago, in the Neolithic Age, humans had already expanded their living scope to every continent in the world with rudimentary technology. In terms of culture, human beings are not Loneliness is just too arrogant.

Hundreds of studies have been reported on animals such as apes, whales, birds and bees. The culture of learning from other individuals has been There are reports. These studies focus on cultural learning and how it affects how animals live, from how to find food, to avoid predators, communicate with other individuals, choose mates, build homes or migrate. All of this adds up to a second form of inheritance, learning-based inheritance, which allows animals to behave beyond genetics-based inheritance, giving animals greater flexibility and innovation. This kind of cultural evolution through inheritance also allows animals to adapt to their environment faster than genetic change.

This is favored by natural selection, but zoologists in the past did not think in this direction at all. Even though Darwin’s theory of evolution has been around for hundreds of years, people’s thinking patterns are still difficult to change. Even scientists who specialize in biological evolution have long regarded some characteristics of human beings as unique, forgetting Darwin's classic saying that nature makes no leaps. If human culture is at the pinnacle of the earth's biota, then there must be huge pedestals below. Without these pedestals, there would be no such king of culture as human beings.

Scientists have determined that the same group of killer whales living in different areas have developed very different hunting traditions, and these traditions require young whales to learn repeatedly, while adult killer whales will repeat it patiently Teaching, this model is not far from our schools. It's just that they learn how to survive, and we learn how to survive better.

Illustration: Only killer whales in Patagonia in the world use beach surfing techniques to prey on young seals. Although there are seals everywhere, including on the beach, only the killer whales here can do this trick. This trick is very dangerous and has the possibility of stranding oneself to death (there are cases of real stranding and then being rescued by human volunteers) , so it requires years of learning, as well as the courage and ability of individual killer whales. Even in Patagonia, not all killer whales can do this trick.

Whale Song Culture

Many whales sing, and Dr. Alan Garland of the University of St. Andrews and colleagues A remarkable cultural phenomenon has been discovered in the songs of humpback whales. Around Australia, some humpback whales are like our showbiz stars, constantly creating new songs that quickly become popular and are then shared by all nearby whales.

What’s more interesting is that the new song will travel southeast across the South Pacific and reach the waters of French Polynesia next year. Now, Dr. Garland, Dr. Rendell and their colleagues have been able to accurately trace the changes from the old song to the new song, revealing how these animal cultures regulate evolution. A male humpback whale that cannot sing a new song is out, and it is difficult to win the heart of a female whale. There are structural similarities between humpback whale songs and human music, and they are by no means random humming.

The team also discovered a rare case of song hybridization, that is, part of an old song is spliced ??together with part of a new song. Although it is still unclear what the function of the humpback whale's song is, or I don’t understand what they want to express, but maybe one day we can share culture through songs and humpback whales. Culture could explain primate brain size, sociality and life-extending history

Dr Sally Street, Professor Kevin Laland and colleagues proposed the above hypothesis and analyzed the brain size of 184 different primate species. Samples were tested. Applying advanced new methods of statistical comparison, the authors found that measures of species' social learning tendencies predict their absolute and relative brain size, as well as their average lifespan and group size. These findings suggest that dependence on culture drove the increase in brain size among the primates to which we belong, and that cultural complexity and genetically based “brain complexity” spiraled toward each other in a coevolutionary manner: The importance of culture extends our understanding of An understanding of the evolutionary biology of own and other species.

Those primates that are most culturally dependent also have longer lifespans and live in larger social groups.

The evolution of brains, animal sociability and longer lifespans have promoted the dependence of animal groups on culture, which in turn has driven further increases in brain size, cognitive abilities and lifespan in some primate lineages.

This is evident in the evolutionary history of the rapid increase in the brains of human ancestors, and this process fed back into behavior and culture, ultimately leading humans to break through a certain brain capacity limit, and suddenly we With a distinct subjective consciousness and will, he separated himself from nature and other living things, and began his journey of loneliness. It all started with the cognitive revolution about 70,000 years ago.

Illustration: The starting point of the geometric progression of human culture is currently believed to have originated from the cognitive revolution about 70,000 years ago. Then came the agricultural revolution, the scientific revolution, and the emerging revolution in which AI enhances human intelligence. The future of each revolution is unpredictable, but we have survived all the way and achieved fruitful results. We can only hope that this AI will Revolutions can also end in comedy. Not all dinosaurs were extinct - some of them eventually flew into the sky

Finally, I must remind everyone to update their knowledge. Dinosaurs were not completely extinct. One of their important branches evolved into today's birds. They are extremely successful from a survival point of view, and there are many very smart birds among them, such as the famous corvids. In addition, I recommend a funny science fantasy film - Dinosaur Dynasty. Introducing the rise and fall of the dinosaurs. Each episode has a protagonist and a storyline.