In the process of evolution, many species had a chance to acquire intelligence, but only man took advantage of it. Dinosaurs, birds, most primates, up to a certain point, quite effectively developed the brain and acquired key qualities: bipedality, grasping hand, sociality. What prevented them from taking the place of our ancestors.
Dinosaurs: carnivorous and very intelligent
The small carnivorous dinosaurs Troodon inequalis, who lived in the late Cretaceous period (84-66 million years ago) in North America and Asia, had a rather impressive brain. As calculated by Canadian paleontologists, the ratio of brain mass to average predicted body mass (encephalization coefficient) in troodonts is six times higher than in congeners.
If we add to this warm-bloodedness (American researchers showed that the body temperature of prehistoric lizards ranged from 36 to 38 degrees), bipedality, a difficult way of getting food (the troodont was a predator, but also ate plants) and a grasping three-fingered hand, then we can conclude: the little theropod had everything it needed to transform into an intelligent creature.
Intellectual evolution was prevented either by an asteroid that fell to the Earth inopportunely, or by a gradual extinction that began forty million years before the complete disappearance of dinosaurs from the planet's surface.
“Some paleontologists have argued that the theropod brain growth rates were comparable to those of our ancestors Australopithecus. If they had not been mowed down by the general extinction, then even with the previous rates of evolution without any accelerations, now they would have a brain size of 1.1 thousand cubic centimeters and would be quite reasonable, "says Stanislav Drobyshevsky, candidate of biological sciences in the book" Reaching Link ", Associate Professor at the Department of Anthropology, Faculty of Biology, Lomonosov Moscow State University.
Reconstruction of the skeleton of Troodon inequalis.
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Ostrich civilization
The descendants of flying lizards - birds - have survived to this day and could also have evolved into intelligent creatures if they had given up flying. They claimed "world domination" 65 million years ago, when mammals were small and weak.
However, the conquest of the heavens had to pay dearly - the bones of the birds became lighter, the brain shrank. Saving weight even forced to get rid of "junk" DNA regions (parts of the genome that do not encode any proteins). In addition, the need to coordinate movements in flight led to an increase in the cerebellum, and there was no room for the development of other regions of the already small brain.
Probably, the return to a terrestrial lifestyle could give their evolution a new impetus, if not for the absence of predators. When there is no danger, the view "relaxes", the brain simplifies. An example of this is kiwi, ostriches and dodo, which do not shine with mental abilities even among birds.
Brothers our monkeys
Why haven't other primates besides Homo become intelligent? The extinct Oriopithecus, according to some reports, could have grown wiser much earlier than our ancestors, but both baboons and gorillas walked with a person literally head to head, but in the process of evolution they turned the wrong way.
In terms of brain size, the first great apes (African proconsul, turcanapithecus) are comparable to modern baboons. They and our ancestors developed at approximately the same rate, and the relative area of the associative frontal cortex is generally the same as we have now.
Moreover, some species of baboons entered the savannah at the same time as Australopithecines, and even mastered it more successfully. At least, they had previously settled from Africa all over the planet. But baboons, unlike humans, chose the path of aggression and strict hierarchy in the monkey flock. The power of the alpha male is almost unlimited, and in any disobedience the baboon shows sharp fangs, which, by the way, our ancestors got rid of in similar conditions. Such a social system works very well, because baboons, which reached their ideal back in the Pliocene, remained anatomically practically unchanged for several million years.
The gorilla has not changed either, because in nature it has almost no natural enemies. Moreover, this monkey, unlike other primates, does not use tools in the wild. But in captivity, it sometimes turns out to be smarter than our closest relatives, chimpanzees. The brain size of gorillas corresponds to the smallest values in modern humans and exceeds the parameters of australopithecines.
Baboons, unlike our ancestors, followed the path of aggression and a strict hierarchy in the flock.
Underwater cities of whales and dolphins
The key to intelligence is a large brain, and its size can be infinitely increased only in an aquatic environment. Therefore, for example, already 33-23 million years ago cetaceans reached the level of advanced hominids in terms of the absolute size of the brain and its tortuosity. But everything is cognized in comparison - in relation to body weight, the brain of dolphins and whales is quite small, and the transformation of paws into flippers does not contribute to tool activity. Although there are cases when female dolphins taught their cubs to look for food, after putting on a sea sponge on their nose.
“Fishing and shrimp fishing is not the most ideal stimulator of mental progress. No matter how difficult it is for a flock of dolphins to drive a school of fish, it remains a corral of fish. They have little chance of being reasonable. The same can be said about pinnipeds. Food specialization, the transformation of legs into flippers, and bodies in a fat wineskin do not contribute to the development of intelligence,”writes Drobyshevsky.
Sea otters (Enhydra lutris) have some chances of creating a marine civilization. These are highly social animals, they have a grasping hand and, as a result, a rich work activity. For example, in order not to stay hungry, they split sea urchins and shells with pebbles. The only thing that hinders the transition of sea otters to the next evolutionary level is that they feel too good in their habitat.
Sea otters have every chance of becoming intelligent creatures.
Alfiya Enikeeva