Man and a tame dinosaur: what would be happening on the planet now if dinosaurs had not gone extinct

Have you ever wondered how history would have turned out if dinosaurs had not disappeared from the face of the earth? Would they have died later? Would humanity ever exist? The plot of a meeting between man and ancient lizards has come to the mind of more than one science fiction writer - just remember “The Lost World” by Arthur Conan Doyle, “A Sound of Thunder” by Ray Bradbury and “Jurassic Park” by Michael Crichton.

But what if humans and dinosaurs had to share the planet equally? But this was quite possible. Narrated by Igor Krai, a regular contributor to the World of Fantasy magazine, where he has been publishing scientific and historical articles since 2004.

The extinction of dinosaurs is usually associated with the fall of an asteroid, which left a huge “wound” on the Earth’s body 65 million years ago - the Chicxulub crater on the Yucatan Peninsula. But even having discovered such convincing evidence of a catastrophe, scientists do not consider the problem settled. After all, the explosion itself, which literally shook the planet, does not explain everything.

Many animals died. Whole species disappeared, but still the majority should have survived. Some groups of reptiles bravely endured the disaster. Squamates (snakes and lizards) not only survived, but also flourished, forming more species than mammals today. Crocodiles are also doing well. And turtles, during their history, which goes back 200 million years, have survived more than one fallen “pebble.”

In fact, the Earth in the Cretaceous period could no longer be considered a planet of lizards. Mammals appeared in the Triassic, around the same time as the ancestors of dinosaurs - thecodonts. Pterosaurs already shared the sky with birds. Among the animals, however, small ones similar to rats predominated, but there were also predators the size of a seasoned Great Dane.

Who should live and who should die out did not become clear immediately after the collision, from which everyone suffered (and the animals, which endure hunger worse, were probably even more so). This issue was resolved later, when the planet recovered from the blow and the survivors began to re-divide ecological niches. The course of this “redistribution of property” has been poorly studied, and its results are still not completely clear.

The appearance of more advanced forms of life - mammals and birds - marked the “beginning of the end” of the era of reptiles. But for tens of millions of years they held their position. To keep up with the times, reptiles have developed several tactical methods.

Small predatory lizards used the natural advantages of reptiles: being content with a small amount of food and day after day, in complete immobility, lying in wait for prey in ambush. It worked then, it works now.

Other lizards, on the contrary, relied on agility, intelligence and independence from the environment and gradually became warm-blooded. In order not to freeze, they “invented” feathers and began to hatch eggs. It was from them that Archeopteryx, and later birds, evolved. During the Cretaceous period, “progressive” feathered reptiles formed the basis of medium- and small-sized animals.

The reasons for their extinction are most obvious. At the end of the Cretaceous period, small feathered lizards looked more like birds than reptiles in the modern sense. It was because of competition that they did not find a place in the sun. If lizards covered with scales were able to contrast their advantages with the weaknesses of the enemy, then those dressed in newfangled feathers had no strengths in comparison with birds. The most they could hope for if they had survived was the space now occupied by ostriches.

Gigantism became another method of adaptation of reptiles. Never before or since have land animals reached such enormous sizes. And the desire of lizards to grow larger has a logical explanation.

Since dinosaurs did not heat the environment, but extracted energy from it themselves by collecting solar heat, they required several times less food. So the same area could support either several animals or one, but larger one. The reptiles preferred the second option. Their enormous mass and low surface-to-volume ratio allowed them to extremely reduce heat loss. Giant sizes (as well as armor and natural weapons) were seen as protection from predators for lizards.

Long and persistent development along this original path has led to amazing results. This is how diplodocus, supersaurs, and seismosaurs appeared - monsters up to 36 meters long and weighing at least 50 tons, whose lifestyle remained an insoluble mystery for a long time.

As a rule, diplodocus is depicted walking briskly across the savannah, with their neck and tail stretched forward and upward. But calculations showed that this dinosaur could not keep its neck raised for long - the weight was too great. How did he move then? Apparently, rarely and reluctantly. The long neck was required precisely in order to clear the maximum area of vegetation from vegetation without leaving the spot. Probably, the lizard remained for a long time in one pasture, occasionally taking a few steps to change the plot.

Every species is subject to pressure from competitors and predators. If the displacement of reptiles by mammals had occurred gradually, the problem of competition would not have been so acute for herbivorous reptiles. In regions with lush vegetation, where there is enough food for everyone, they would maintain their position. It's worse with predators. Here the animals would leave them no chance.

But this only applies to small and medium-sized dinosaurs. Giants that had no natural enemies in the Cretaceous period would not have them now. By making it a habit to guard clutches of eggs and offspring until they reached the size of a bull, large dinosaurs could survive in hot regions.

What would this give to humanity? Perhaps food. Reptile hunting is easy. Of course, how to kill a diplodocus without artillery is a complex question, but a purely technical one. Even in the Mesolithic, people killed mammoths and whales. Perhaps reptiles would even be domesticated and bred, since they require little food compared to cattle.

But here the prospects are controversial. Most likely, giant dinosaurs, like turtles, lived for centuries and grew too slowly. There can be no talk of any use of reptiles for transport and especially military needs. They are too slow and stupid for that.

The gigantism of herbivores led to the gigantism of predators, which in those days were not as bloodthirsty as they were scary in appearance. The monstrous seven-ton Tyrannosaurus rex shared the same hunting territory as a pair of lions. Perhaps he devoted most of his time to introspection and deep reflection on the meaning of life, making sure that rivals did not enter his area.

Who the tyrannosaurus hunted is a mystery. Even medium-sized dinosaurs, such as the nine-ton Triceratops, were too big for him. Small iguanodons, the size of a small elephant, clearly ran faster. But the tyrannosaurus could not sneak up on the victim unnoticed. He probably tried to chew through the shells of sedentary armored lizards and ate carrion, using his teeth to cut up a huge carcass and scare away other contenders for it. One deceased diplodocus could provide food for a couple of dozen such monsters.

If the tyrannosaurus was a scavenger, it would not be lost in the modern savannah. Yes, his talents as a hunter are questionable. Hardly any of the modern animals is so careless as to get to dinner for such a slow and - most importantly! - a noticeable monster. But no other predator (including extinct ones) could have fought off its prey from the Tyrannosaurus rex.

Living up to its tyrannical name, the lizard would easily receive the lion's share of the lions themselves, taking the place of a “super scavenger” in the ecosystem. Tyrannosaurs would even serve a useful function, destroying the bones of elephants and rhinoceroses that are now accessible only to the teeth of porcupines. The porcupines would have to make room.

Despite the controversial "predation", the huge lizards would pose a serious threat to the southern tribes. After all, man is one of the few creatures that cannot escape from a tyrannosaurus. A sad fact for us would be noted with satisfaction by a reptile attracted to settlements by the smell of meat. Driving off a lizard that was too big and stupid to fear humans, and practically invulnerable, would be problematic. It would be possible to fence oneself off from him only with a fortress wall.

Most pterosaurs were creatures, although bizarre, but lacking any real Jurassic flavor. They ranged in size from a sparrow to an albatross, were covered with colored down and did not resemble “flying crocodiles.” Like terrestrial lizards, feathered lizards were doomed in conditions of fierce competition. The flight feathers of birds turned out to be more effective than membranes.

But pterosaurs had their own trump cards. This order includes such giants as Pteranodon with a wingspan of 6-8 meters, as well as Ornithocheirus and Quetzalcoatlus - real legendary monsters, whose wingspan reached 12-14 meters.

The very existence of giant pterosaurs seriously puzzled researchers: in theory, these lizards could not fly. Since as the mass in the cube increases, the force increases only in the square, only an animal not heavier than 16 kilograms will have the specific power required for flight. Quetzalcoatlus weighed about a quarter of a ton. Most likely, he was only gliding, jumping off the cliffs and “clinging” to the rising air currents. Using the wind, he did not waste energy on flight, but the maneuver, elementary for a seagull - to dive, snatch a fish from the water, gain altitude and return home - was extremely difficult for him.

The advantages of reptiles clearly helped the winged lizards survive. Hunting fish too large even for albatrosses, they would have no competitors. And the size, which feathered predators simply cannot achieve, would protect pterosaurs from natural enemies. Most likely, they could survive to this day.

Huge “living hang gliders” would pose neither danger to people (this monster simply would not risk descending to low level flight over land), nor interest as prey. But if we think purely theoretically, then Quetzalcoatli and Ornithocheirus are the only real flying creatures capable of carrying a person on their back. And even if they had not been tamed, just watching these animals fly would have quickly made our ancestors think about gliders.

If the death of land dinosaurs was predetermined, then science cannot yet explain the disappearance of aquatic dinosaurs. They had to not only survive the catastrophe, but also maintain their positions in the evolutionary struggle.

This is partly what happened. Crocodiles not only survived, but also maintained a dominant position in tropical rivers, without losing the top of the food pyramid to mammals. Invading the territory of crocodiles from the sea, dolphins and manatees have achieved only minor success.

Reptiles also feel great in the open sea. Several centuries ago, concentrations of sea turtles turned out to be a real obstacle to the caravels. For the aquatic environment, reptiles represent an ideal compromise. On the one hand, unlike fish, they breathe through their lungs. This is a big advantage: it takes a lot of effort to pump water through the gill slits, and the oxygen in it is enough for the cat to cry. On the other hand, unlike mammals, reptiles use oxygen very sparingly. They have to surface to breathe much less often.

Therefore, the death of ichthyosaurs, plesiosaurs and pliosaurs looks like an “accident” in which there is no evolutionary logic. They did not even fall in competition with cetaceans, which appeared much later, but simply disappeared. If not for the impact of an asteroid (combined with some still unknown factor), sea lizards might still be with us.

What would the seas look like in this case? Surely there would be fewer whales. After all, mammals that switched to an aquatic lifestyle would have to compete with reptiles that were already perfectly adapted to it. True, this transition could have occurred in the polar seas, where the lizards would not have been able to establish a defense. But the appearance of whales would not have exterminated the ichthyosaurs. The sea is large, there is enough food for everyone, and species defeated in the struggle for existence, as a rule, do not disappear completely, but only decrease in number.

If not for an ancient catastrophe, the waves of tropical seas would have cut through the sharp dorsal fins of huge fish lizards. Their size would give them some protection from killer whales. Another method of defense would be to increase the depth and duration of the dive.

But it is difficult to imagine a reptile capable of withstanding a fight with a sperm whale (or the same killer whales, but attacking in a group). Pangolins would not be able to maintain their position at the top of the food pyramid on the open sea. Most likely, plesiosaurs would have continued to thrive in tropical shallow waters. To thrive, since not a single large mammalian predator has yet laid claim to this zone. The lizards would easily “persuad” the sharks to make room.

How would sea lizards change people's lives? Ichthyosaurs, perhaps not at all. Over time, they would attract the attention of whalers, but would be considered difficult prey. After all, a lizard would stay in greater depths than a whale, and would appear much less often on the surface to breathe. Even detecting it would be difficult. In addition, the value of the trophy is low. Whales are hunted for their fat, which they need for insulation. The ichthyosaur, being in complete thermal harmony with its environment, could only provide tough meat.

Another thing is plesiosaurs. By pushing sharks out of the shallow waters, they would significantly diversify the life of coastal tribes with adventures. As with crocodiles, the gastronomic interest of people and lizards would be mutual. But it would be incomparably more difficult for a person to put up with their proximity, because the plesiosaur has a neck.

The fact is that you don’t need a neck to hunt underwater. Water is too dense a medium for sudden maneuvers. Therefore, neither crocodiles, nor whales, nor penguins have long necks. Even snakes and serpentine fish do not have it - their entire body is elongated. The plesiosaur had a compact body and a flexible swan neck. He hunted by swimming near the surface and snatching prey from the depths with a swift throw.

Traveling across the southern seas and rivers on rafts and pirogues for thousands of years was possible only because large aquatic creatures (not counting hippos), capable of easily turning over or breaking a fragile and fragile boat, did not think of doing this. The whale, being harpooned, tries to escape, but does not even defend itself. When viewed from under the water or along its surface, the boat seemed to the monsters to be a large, strange, but clearly inanimate object, which means it was obviously inedible and safe. Only the person who fell into the water was attacked.

But the plesiosaur looked for prey not from below, but from a height of 3-4 meters above the water. From this angle, the boat looks like a wooden dish with food.

Thrills would also await people on the banks of rivers. A lurking crocodile can grab a victim only by bringing it to a minimum distance, and therefore is not very dangerous for those who have not yet entered the water. The plesiosaur, being able to camouflage just as skillfully and wait just as patiently, could suddenly attack its prey on the shore, quickly “shooting” its neck from under the water. Of course, in shallow reservoirs there would be no need to fear an encounter with a fifteen-meter monster, but a smaller lizard would drag a person into the water and drown a person without difficulty. And it is more difficult to notice him in time than a giant.

A world where aquatic predators are dangerous only to swimmers and a world where powerful creatures that can attack boats exist are different worlds. A multi-ton monster, fast and unnoticeable in the elements that are native to it, but alien to man, is almost invincible. It is difficult to imagine what sailors could have opposed him even in the Iron Age. Large and strong ships would have been out of danger, but their construction might not have come to fruition. In tropical regions where lizards were common, residents would avoid even going near water. An encounter with a plesiosaur at sea would mean inevitable death.

The impact of the asteroid did not so much change the animal world as impoverish it. And this is a common property of all disasters. The space rock only brought the inevitable closer. The lizards could hold back the onslaught of animals for a long time, but not forever. But if the change of eras in the animal world had occurred less dramatically, the giant reptiles would have had time to gradually adapt to the world of mammals and birds. Having ceded their dominant positions, they would not have disappeared completely.