Dinosaurs where they lived. When and where did dinosaurs live? Infographics

The Age of Dinosaurs, or Eras and Periods of the Earth

Scientists have identified several stages in the history of the Earth. They are called "era". Eras are divided into periods, each of which lasted several tens of millions of years. In different books The beginning and end years of eras and periods may vary slightly: There are different opinions in science. The Paleozoic era, or Paleozoic, began 570 million years ago. Over the 340 million years that it lasted, the living world changed amazingly. The waters and land were populated. Vertebrates arose (although the time of mammals and birds had not yet come). The living world has become incredibly diverse. But the molecules that made up the organisms of that time remained approximately the same. These molecules have changed little to this day. So the molecules that make up the human body are very similar to the molecules, for example, of an ancient crustacean. The Paleozoic era is divided into 6 periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian. At the beginning of the Paleozoic, an amazing “explosion” of life occurred: many species of invertebrates were formed. But at first this happened only in water, especially in warm seas. The land remained deserted. Mastering sushi. Somewhat earlier than 400 million years ago, plants began to populate the land. At first they were inconspicuous sprouts. But after millions of years, the Earth was overgrown with dense forests. Following plants, invertebrate animals mastered life on land. The abundance of food on land attracted lobe-finned fish. Only they could, relying on their unusual limbs, move outside the water. And primitive lungs allowed these fish to breathe air. Many millions of years passed, and lobe-finned fish, gradually changing, turned into new biological species. But these were already animals of a new class - the class of amphibians (amphibians). Carboniferous period of the Paleozoic era (or Carboniferous for short). Began 345 and ended 280 million years ago. In the humid heat, forests grew quickly and abundantly. After millions of years, these trees turned into coal. Amphibians reigned in the swamps and surrounding forests. And tiny ones. And huge five-meter tailed predatory stegocephals. At the end of the Carboniferous, the first reptiles appeared. The Permian period, or Permian (280-230 million years ago), was marked by the rapid emergence of new species of reptiles. The Mesozoic era, or Mesozoic, began 230 million years ago and lasted 165 million years. During this time, higher (flowering) plants arose. Giant lizards (dinosaurs, ichthyosaurs and others) appeared, reigned on the planet and mysteriously died. Mammals and birds evolved. The Triassic period of the Mesozoic, or Triassic (230-190 million years ago) was marked by the dominance of reptiles on land, in water and in the air. The most famous of these reptiles are dinosaurs. Dinosaurs walked either on four legs or on two. It is very likely that some dinosaur species were warm-blooded. Judging by the tracks of dinosaurs and the remains of the eggs they laid, these animals were caring parents. Dinosaurs laid eggs in piles of plant debris. As these remains decomposed, they released heat, and the clutch of eggs was heated. And the mother, remaining nearby, guarded the nest (the relatives of dinosaurs, crocodiles, also do this). Recently, paleontologists discovered traces of the tragedy: a small skeleton of a female dinosaur lying on a fossilized clutch of eggs. Probably the mother warmed the eggs and died, but did not leave them. The eggs of some other species may also have been incubated by dinosaurs. It is unknown what color the skin of dinosaurs was. Perhaps, like many lizards today, snakes are bright and colorful. This is how artists draw dinosaurs. The name comes from Greek words meaning "horrible" And "lizard". In fact, not all dinosaurs are “terrible.” Dinosaurs of the Triassic period were, as a rule, small, graceful, fast animals. They ran on their hind legs, and their long tail helped them maintain balance. And in the next almost one and a half hundred million years, when dinosaurs dominated the land, they were mostly small. Some are as tall as a man, some are a little bigger, and some are even as tall as a chicken. The Jurassic period of the Mesozoic, or Jurassic (190-135 million years ago) is the era of the appearance of gigantic dinosaurs. Supergiants. During the Jurassic period, the largest animals on land appeared -. A heavy body on thick legs, with massive blunt claws on the toes. The neck is long. The tail is even longer. Without moving from their place, moving only their necks, they plucked and ate whole mountains of greenery.

The brain of sauropods is too small in relation to the body - about the size of a fist, or even less. Despite this, the behavior of these lizards was most likely complex. They lived in herds (judging by the fossilized traces). Perhaps together they defended themselves from predators that appeared in the Jurassic. But how did they fight back? This is unknown.

Powerful predator of the Jurassic period. A fast animal weighing about a ton, armed with huge claws and teeth that look like curved daggers. Allosaurs attacked large herbivorous dinosaurs in packs. Carnivorous dinosaurs could not chew food with their cutting teeth. They swallowed pieces of meat whole. With their teeth, predators ripped open the tough skin of their prey and crushed bones.

The largest of these dinosaurs reached 9 m in length. Such a mountain consumed tons of green food. Sharp long bone spikes stood out on the tail to fight off predators. The bone plates on the back are apparently shields, salvation from enemy teeth and claws. The Cretaceous period of the Mesozoic, or Cretaceous (135-65 million years ago) is the era when dinosaurs and other reptiles continued to rule the Earth. And at the same time, there were more and more mammals (they appeared in the Triassic) and birds (they appeared in the Jurassic). Mammals lived side by side with dinosaurs for many millions of years, hiding and running away from these ferocious predators. It was no easier for the birds: although dinosaurs could not fly, they even reached bird nests in trees. Reptiles in the sky. Pterosaurs (the name of the order of winged reptiles) took to the air at the end of the Triassic period and flew until the end of the Cretaceous. Each of their wings consisted of a leather membrane that was stretched between the body, limbs and one of the surprisingly long fingers of the forelimb. The remaining fingers were ordinary, and the reptiles clung to branches and stones with them, resting.

Animals with thin, hollow (like bird) bones. The first pterosaurs had a tail and teeth. After millions of years, pterosaurs got rid of this “heaviness”. Pterosaurs were obviously warm-blooded. Their body was covered with hairs - “wool”. The brain of these reptiles was well developed. Small pterosaurs (from 8 cm in wingspan) caught insects. Large ones (wingspan 1 meter, 2, and 6 meters) snatched fish, cephalopods and other food from the water. Surely pterosaurs nursed their young. Pterosaurs are not dinosaurs! Reptiles that are not extinct. During the Mesozoic era, snakes, turtles, lizards, and crocodiles appeared. They were not very different from the current ones. Reptiles in the sea. The most adapted to life in water were ichthyosaurs. They appeared back in the Triassic. Outwardly, they are strikingly similar to dolphins. The reason is the same lifestyle. Only the tail fin of ichthyosaurs is not horizontal, like that of dolphins, but vertical.

In water, reptiles have no place to lay eggs, so ichthyosaurs immediately gave birth to “ready” babies. A variety of long-necked plesiosaurs, crocodile-like giant mososaurs, and other aquatic lizards hunted fish and cephalopods. And sometimes they fought fiercely with each other. All fossil aquatic reptiles are not dinosaurs! Predatory lizards were distinguished by a relatively large and developed brain, and their behavior was complex. Apparently, some even knew how to hunt together, “coordinating” their actions. Catastrophe. Until the end of the Cretaceous period, reptiles dominated both land and sea. It was at the end of the Cretaceous that the largest land predator of all eras appeared -. About 65 million years ago, dinosaurs and pterosaurs, all sea lizards, disappeared almost simultaneously. They all died out without leaving descendants. Cephalopods - ammonites and belemnites - died. What happened? What is the cause of this environmental disaster? There are many assumptions, and all of them are controversial. Here is one of them: a colossal meteorite, even an asteroid, crashed into the Earth. The monstrous explosion created such a cloud of dust that the sunlight went dark for a long time. Living conditions deteriorated so much that the dinosaurs could not bear it. Everything is very likely. But why did the closest relatives of dinosaurs - crocodiles - survive this environmental disaster? The causes of the great extinction at the end of the Cretaceous period are still a mystery to science. Birds appeared on Earth in the Jurassic period. The first fossil bird found was named.

The ancestors of birds are very close to the ancestors of dinosaurs and crocodiles. The external similarity between birds and dinosaurs is undeniable. There are many similarities in other properties of the body of these animals (for example, scales on the legs of birds). However, one cannot assume that birds are descendants of dinosaurs. They are their close relatives. Archeopteryx was covered in feathers. Undoubtedly, he was warm-blooded. He could fly, but not for long. However, the skeleton of the tail of Archeopteryx is almost like that of a lizard (later this part of the spine disappeared in birds). The mouth is toothy. There is no beak yet. But there were three fingers left on each wing - to cling to tree branches. It is still unclear how the small (magpie-sized) Archeopteryx used its wings. Did he flutter from branch to branch? Or he ran on the ground and, jumping and flapping his wings, grabbed flying insects with his teeth and escaped from predators. Archeopteryx still has many signs of reptiles. Gradually, such signs became less and less. Already in the Cretaceous period, many different birds screamed (they did not yet know how to sing) in the crowns of trees. In swift, agile flight, the birds snatched prey from under the beaks of less agile pterosaurs. Mammals. The first mammals appeared at the end of the Triassic period - later than dinosaurs, earlier than birds. The ancestors of mammals were animal-like reptiles. They differed in many ways from other reptiles - the ancestors of dinosaurs. The beasts were most likely warm-blooded animals (at least many of them). Probably, instead of scales, their skin was covered with hair. There were other features of the body. So, there were many different glands on the skin that secreted sweat and other fluids. Perhaps in some species of these animal-like reptiles the glands secreted a liquid similar to milk. Such liquid could be licked and thus fed by the hatchlings from the eggs (as baby platypus do today). Then the cubs began to be born and develop as it happens today in marsupials. Finally, a special organ arose for feeding the baby inside the mother’s body - the placenta. The first mammals were small animals (like a shrew, like a hedgehog). For many millions of years they existed secretly in the dangerous world of dinosaurs. Apparently they were hiding in the thickets. They hunted only at night, for insects, shellfish, and other edible things. Perhaps they ate reptile eggs. , or Cenozoic. It began approximately 65 million years ago and continues to this day. During this time, mammals conquered land, water and air. Adapting to new living conditions, mammals have changed. Evolution continued.

Life on our planet began about 4.5 billion years ago, but for more than 4 billion years it existed in the form of very primitive, tiny single-celled creatures that could not yet be divided into animals and plants.

Gradually, organisms became more complex and diverse. In the Cambrian period, about 550 million years ago, algae, sponges, mollusks, worms, coelenterates and many other new forms of life appeared. This time was called the "Cambrian explosion". Millions of years passed. The first vertebrates arose in the ancient seas - fish-like fish and lobe-finned fish.

The turning point in the evolution of life on Earth was the emergence of animals from water to land. This process took a long time - about 100 million years. At first, lobe-finned fish came onto land only for a short time. True terrestrial vertebrates - armored-headed amphibians, or stegocephals - appeared in the Devonian after their ancestors learned to get food on land. In the Carboniferous period, stegocephalians began to be replaced by the first reptiles that appeared - cotylosaurs, which became the ancestors of all other groups of reptiles. In the middle of the Permian period, cotilosaurs became extinct, giving way to more developed animal-like vertebrates - therapsids, among which were both herbivorous and predatory species. Animal-like animals remained the most common reptiles in the Early Triassic. At the end of the Permian period, thecodonts, or archosaurs, the most ancient lizards, appeared. The evolution of reptiles proceeded very quickly and violently. The Mesozoic era became the real kingdom of reptiles. It began about 235 million years ago and lasted approximately 160 million years. The Mesozoic is divided into three periods: Triassic, Jurassic and Cretaceous. The first two periods were much shorter than the third, which spans about 70 million years. At that time, there were no competitors for reptiles from other animals, so under the influence of the diversity of living conditions, a variety of types of reptiles appeared. They have adapted to a wide variety of terrestrial conditions. Subsequently, many of them secondarily adapted to life in water (ichthyosaurs, plesiosaurs). Some became aerial animals (pterosaurs). At the end of the Triassic period, the first land turtles and crocodiles appeared, which survived all natural disasters and survived to this day. Dinosaurs also appeared in the Triassic period. The oldest known dinosaurs were Eoraptor and Herrerasaurus.

Main groups of dinosaurs

Dinosaurs descended from thecodonts, namely from slender, fleet-footed ornithosuchians, which are considered the direct ancestors of dinosaurs. Among dinosaurs, two groups are distinguished: ornithischians and lizards. The pelvis of the first group is similar to the pelvis of birds, and the second is similar to the pelvis of modern reptiles. Ornithischians also had an additional bone at the end of the lower jaw that covered the jaws in the form of a horny beak. There was another group of dinosaurs - segnosaurs. Their structure had features of both ornithischians and saurians, and some features are generally characteristic only of segnosaurs

In the Jurassic period, lizards flourished. The first of them were predators, they ran on strong hind legs and grabbed prey with their front legs. Later, herbivorous species evolved from carnivorous dinosaurs. They needed a huge amount of food, their body weight was constantly increasing. They used all four limbs while walking. Based on the structure of their legs, they were called lizard-footed dinosaurs, or sauropods. This group includes 40 genera. The bipedal predators were called beast-footed dinosaurs, or theropods. There are 150 genera.

Lizard-hipped dinosaurs Theropods

These dinosaurs walked on their hind legs with three toes armed with sharp claws. Some of them were ferocious hunters, others were scavengers. All theropods had backward-curved teeth. They did not know how to chew food and swallowed whole pieces of prey. They came in a variety of shapes and sizes - from a sixty-centimeter saltop to a fourteen-meter tyrannosaurus.

At the end of the Triassic period, small and very graceful coelurosaurs existed. They had light, hollow bones. They ran very fast on long hind legs, the front legs were half as long. To hunt, coelurosaurs gathered in packs, so they could attack large animals. This group includes the three-meter-long Coelophysis (“hollow form”) and the five-meter-long Halypicosaurus (“agile lizard”). Even more graceful species of coelurosaurs lived during the Jurassic period. These are a two-meter ornitholestes (“bird predator”) and compsognathus (“graceful jaw”), only 60 cm long and weighing 3kg. According to one hypothesis, Archiopteryx evolved from coelurosaurs. The descendants of Coelophysis also became powerful predators (Allosaurus, raptors, tyrannosaurus).

60 Allosaurus ("another reptile") skeletons have been found in deposits from the late Jurassic period. The largest of them reached 12 m in length and weighed 1-2 tons. Allosaurus had three toes with curved claws on its front paws. Its teeth had sharp, serrated back edges that cut through hide and bone like a saw.

Its close relatives, even more gigantic (up to 13m in length and weighing up to 7t), lived in the Late Cretaceous period. These are Giganotosaurus ("giant southern lizard") and Carcharodontosaurus ("huge shark-toothed lizard"). The skull of the carcharodontosaurus reached one and a half meters in length, and its mouth was so large that it could swallow an adult person whole. One of the most dangerous predators of the Late Cretaceous was the Tyrannosaurus rex (“tyrant lizard”). Its height reached 5 m, length - up to 14 m, and weight - up to 5 tons or more. The meter-long skull of this bloodthirsty lizard, flattened on top and on the sides, had a huge mouth armed with fifteen-centimeter teeth.

In the Late Cretaceous period, there was also a nine-meter Gorgosaurus. Outwardly, it resembled a tyrannosaurus, but weighed about a ton or a little more. In its monstrous mouth there were 60 sharp ten-centimeter teeth. Scientists suggest that Gorgosaurus was clumsy, and therefore probably a poor hunter. The most accessible food for him could be slow animals, carrion and the remains of meals of other predators.

Even larger (14m or more in length, 6m in height) was the Tarbosaurus (“terrifying lizard”), also similar in appearance to a tyrannosaurus.

Albertosaurus (length 9m, weight 2.5t) and Megalosaurus (length up to 9m, weight 1t) were not inferior to these dinosaurs in bloodthirstiness.

Some of the most terrible predators of the Cretaceous period were dromaeosaurs, or raptors. They were distinguished by a huge sickle-shaped claw on each hind leg. They hunted in herds, so they could attack animals larger than themselves. Before biting the victim, raptors used grasping arms and long claws on their legs.

The most ancient raptor was Velociraptor, which lived in the Late Jurassic period. Its length was from one and a half to 4 m, weight up to 100 kg. Its sickle-shaped claw reached 15 - 20 cm. Deinonychus (“terrible claw”) had similar claws. Its height did not exceed one and a half meters, and its length was 3 -4 m. The average weight of these lizards was 70 -80 kg. The largest of this group was Utahraptor (“Utah Snatcher”), which lived in the Early Cretaceous period. It reached 6 m in length and weighed about 900 kg. Towards the end of the age of dinosaurs, in the Late Cretaceous period, some raptors became increasingly bird-like. This is reflected in their names: avimim (“imitating a bird”), strutomim (“imitating an ostrich”), dromshcheomim (“imitating a chicken”). They could eat not only meat, but also fruits and soft parts of plants, and also caught insects. Instead of teeth, they had keratinized jaws. And oviraptor (“egg stealer”) had only one tooth for splitting the shells of large mollusks, the meat of which it ate. A bone appeared on the wrist of these lizards, thanks to which raptors could move their forelimbs to the sides, just like birds spread their wings. These long-legged animals apparently ran faster than other dinosaurs and were still predators. For example, the Troodon (“tearing teeth”) had large eyes and keen hearing. Apparently he was a good hunter. Ostrich-like dromaeosaurs were an intermediate link between Archiopteryx and birds.

Many people believe that dinosaurs are large, ferocious, and extinct reptiles. For the most part this is true, but there are a number of misconceptions. Dinosaurs came in many shapes and sizes. They were the largest land animals of all time, but a large number of dinosaurs were smaller than a turkey.

Fossil remains show that some of the most advanced dinosaurs had feathers or feather-like body coverings, but many did not fly and may not even have glide. Archeopteryx, long considered the first bird (though this status is now questionable), is the most famous example. The feathers of this bird-like dinosaur were not so much an adaptation for flight as they helped the animal retain heat.

Many people believe that the extinct flying reptiles called pterosaurs were dinosaurs. In fact, they were only their closest relatives. Pterosaurs had hollow bones, relatively large brains and eyes, and, of course, folds of skin along the upper limbs attached to the phalanges of the fingers. The family includes pterodactyls, which were distinguished by a long bony process on the head and a lack of teeth. Pterosaurs survived until the mass extinction event 65 million years ago, after which they suffered the fate of dodo birds, marine reptiles and other dinosaurs.

Difference in pelvic bones

The remains of dinosaurs were first discovered in the 19th century. In 1842, paleontologist Richard Owen coined the term, which comes from the Greek "deinos" - "terrible" or "terrifyingly huge" and "sauros" - "lizard" or "reptile". Scientists classify dinosaurs into two groups - lizard-hatched and ornithischian - based on the structure of the animals' pelvic bones.

Most of the well-known dinosaurs, including Tyrannosaurus rex, Deinonychus, and Velociraptor, are members of the group of saurischian dinosaurs. The pelvic bones of these animals are extended forward, like those of more primitive creatures. They often had a long neck, large and sharp teeth, a long second finger, and the first finger was directed perpendicular to the others.

Saurischians are divided into two subgroups - the four-legged herbivorous sauropods and the bipedal carnivorous theropods (birds of today are actually theropods).

Theropods walked on two legs and were predators. “Theropod” means “beast-footed,” and these were the most terrifying and most expressive dinosaurs, such as Allosaurus and Tyrannosaurus.

Scientists tried to figure out whether such large theropods as gigantosaurus and spinosaurus actively hunted, or whether they simply ate skeletons. Evidence indicates that these animals were unprincipled hunters: they could grab prey, but they were not above killing animals. When archaeologists discovered bones with markings, they wondered whether theropods were cannibals. It turned out that the animals could feast on fallen representatives of their own species, but did not actively hunt each other.

Sauropods were herbivores with long necks and tails. They were among the largest animals that ever existed on our planet, but their brains were obviously very small. This family includes such slow-moving leaf-eating giants as Apatosaurus, Brachiosaurus and Diplodocus.

Ornithischian

Mild plant eaters include animals such as the horned Triceratops, the spiny Stegosaurus, and the shell-covered Ankylosaurus.

A distinctive feature of these herbivorous species is the presence of a beak. They were smaller than sauropods, led a herd lifestyle and often became prey for large dinosaurs. Interestingly, ornithischians changed their mode of locomotion from bipedal to quadrupedal at least three times during their evolutionary history.

Marine reptiles

During the age of dinosaurs, a lot was happening under the surface of the ocean. The seas were teeming with creatures such as ichthyosaurs, predators similar to modern tunas and dolphins. This large subclass of marine reptiles almost completely went extinct at the end of the Jurassic period.

Are dinosaurs as scary as they are described? The word "dinosaur" means "terrible lizard." However, many of these animals did not look like lizards, and did not look at all like terrible ones. In the article we will talk about who dinosaurs are, what era they lived in, how many years they roamed the earth and what is the life expectancy of these lizards.

Who are dinosaurs

Before we touch on the question of how many years ago dinosaurs lived, let’s clarify who they are in general. Dinosaurs are extinct land vertebrates. Today, scientists count about 500 different genera and more than 1000 different species.

Why were these vertebrates called dinosaurs? This happened in 1842. The term was introduced by English biologist Richard Owen. This was done for the convenience of describing these species of extinct animals. The fact is that the bones of large vertebrates found by archaeologists in different places on the planet were of gigantic size. This amazed scientists. It was obvious that the creatures that lived on the planet many thousands of years ago were not just large, but huge. From the ancient Greek "dinosaur" - "terrible, terrible."

Who was the first?

How long did dinosaurs live? We'll find out a little later. In the meantime, it's time to find out whose remains were discovered first. This is a stavrikosaurus. A predator whose size resembles a large dog. It weighed about 30 kg, with a height of 80 cm. The only difference from a dog is that the staurikosaurus moved only on its hind legs.

Second place goes to Herrerasaurus, or Herrerasaurus. This is a two-legged “terrible lizard” that is an order of magnitude larger than the Staurikosaurus. Is a predator.

Habitat

How long did dinosaurs live and where? Their habitat was vast - the entire planet. The remains of lizards were discovered both in South America and in the territory of modern Egypt.

Classification

These vertebrates are conventionally divided into two types:

1. Lizard-pelvic.
2. Ornithischians.

Why “conditionally”, how do they differ? The direction of the bones. Saurischian dinosaurs had pubic bones pointing forward. Ornithischians were distinguished by bones that were initially directed backwards.

When did dinosaurs live?

We have almost reached the main question of this article: how long did the dinosaur period last? These animals lived safely on the planet in the Mesozoic, namely from the late Triassic period to the end of the Cretaceous. This is from approximately 225 million years ago to 66 million years.

How long did dinosaurs live?

The differences are not only in types

All the “terrible lizards” were completely different: predators and herbivores, small and large, bipeds and quadrupeds. The average lifespan of dinosaurs of various species also varies. Small representatives lived very short, 20-30 years. Large individuals lived for 2-3 centuries. It is known that large ones reached sexual maturity only at 40-50 years of age.

How many years ago did dinosaurs live? They appeared about 225 million years ago.

Causes of extinction

Scientists are still arguing about this topic. It is very strange why so many fairly large and well-adapted creatures became extinct. There are quite a few hypotheses about this, the most common are the following:

1. A giant meteorite falls to earth.
2. The split of continents.
3. Changing of the climate.
4. Extermination by predatory species first of herbivores, and then of their own kind.

How long did dinosaurs live? We found this out. Now let's go over some very interesting facts about the "terrible lizards":

1. The largest of them was Seismasaurus. This giant was distinguished by its calm disposition and the fact that it ate plant foods.
2. Titanosaurus is the heaviest of all its “brothers”. Its weight, according to scientists, reached 80 tons.
3. Our world is inhabited by the closest relative of vertebrates that became extinct many thousands of years ago - the crocodile.
4. Compsognathus is the smallest representative of the dinosaurs. His weight was about 2.5 kg.
5. Tyrannosaurus is the most terrible predator of all the dinosaurs that once inhabited our planet.
6. Brachiosaurs are the longest representatives of all dinosaur genera. The body length of the brachiosaurus could easily reach 50 meters.
7. Huge and scary dinosaurs had very small brains. The brain size of some individuals was no larger than a walnut.
8. Tyrannosaurus's teeth reached 30 cm.
9. Young tyrannosaurs gained several kilograms daily as they grew.
10. The most protected was the ankylosaur. On the tail there was a bone mace with sharp spikes. And on the body there was armor made of spikes.

Let's summarize

The article examined questions about who dinosaurs were, how many years ago they lived, in what period, what was the life expectancy of this or that representative of the genus. Let's remember the main aspects.

Dinosaurs are vertebrates that went extinct many years ago. They appeared on the planet about 225 million years ago. How long did dinosaurs live? They lived on earth for about 160 million years. Life spans fell on The largest dinosaurs lived safely to the age of 200-300 years. As for small individuals, their age barely reached 30 years.

Conclusion

The life of dinosaurs is a mystery that scientists are still trying to discover. Perhaps someday they will be able to do this.

DINOSAURS
When were dinosaur bones first discovered?
Around 1820, the attention of English and French researchers was attracted by fossilized teeth and large bones. Studying them, they came to the conclusion that the fossils belong to unusually large lizards - reptiles that lived in prehistoric times. In 1822, the English doctor Parkinson assigned the name Megalosaurus (giant lizard) to one of the finds in the collection of geologist Buckland. In 1924, Bookland began to describe it and gave it a scientific designation. It was then that the dinosaur was first recognized as such and given its name. The second sensational message appeared in 1825. It was made by the English. Doctor Mantel. Three years ago, his wife Mary found a cobblestone in the street rubble containing teeth measuring 4 to 5 cm in size. Such teeth and fossilized bones were also discovered in a nearby quarry. Since the teeth resembled in shape the teeth of iguanas - lizards found in the Center. and South America, - Mantel named the newly discovered animal iguanodon (iguana tooth). Following this, dinosaur remains were discovered in England. In Germany in 1837, the bones of a certain dinosaur were also found, which Professor Hermann Meyer called a plateosaurus (plain lizard). At that time, it did not occur to any of the researchers that the discovered animals, known only from fragments, belonged to an independent species of reptiles. London professor Richard Owen was the first to come to this conclusion when more complete skeletons were discovered. In 1841, he proposed that all representatives of this group of reptiles be called dinosaurs - terrible or terribly large lizards. What remains of dinosaurs?
Mostly their bones were preserved. Finding a complete skeleton or skull with teeth is an extremely rare occurrence. Most often, paleontologists (paleontology is the science of animals and plants in the geological past) have to be content with fragments of bones and individual teeth.
The soft parts of the body could not be preserved, but sometimes there are prints of areas of skin on which the smallest details are clearly visible. Findings of fossilized dinosaur eggs or pieces of shells continue to cause a sensation. Unfortunately, one can only guess about their belonging to one or another type of dinosaur. Even if a nest with eggs and a skeleton lying on top are discovered, it cannot be said with complete certainty that they belong to the same species.
Of particular interest are remains of food preserved in the stomach area of ​​the dinosaur, for example, lizard bones between the ribs of the small carnivorous dinosaur Compsognathus. What the dinosaur ate can be determined from its fossilized excrement.
Body traces, especially foot prints, are very valuable, since they can be used to judge the lifestyle, speed of movement and mass of animals.
Why do dinosaurs have such strange names?
Each new species of dinosaur gets its own name. The role of godfather is played by a scientist who studied the find in detail and made a comparison with already known species. A “birth certificate” is a publication in one of the special scientific journals.
The name is always made up of two parts: the name of the family (with a capital letter) and the name of the species (with a lowercase letter). In accordance with scientific tradition, Latin and Latin scripts are used. When choosing a name, they often also resort to Greek words, geographical names and proper names. Most often, the name reflects the characteristic properties of a given type of dinosaur or its remains found. Stegosaurus armatus (stegosaurus armatus, an armed lizard with plates on its back) - the name is given by the plates and spines characteristic of this dinosaur. Ceratosaurus nasicornis (horned nasal horn dinosaur) - This dinosaur has a large horn on its nose. Diplodocus longus (long double beam) is an elongated dinosaur whose distinguishing feature is the presence of double processes on most of the caudal vertebral bones.
Often the name reflects the location of the find, for example in the name Mamenchisaurus hochianensis (Mamenchisaurus hechuanensis). Mamenchi and Hechuan - discovery site and locality in China. Lesothosaurus (lesothosaurus) is found in Lesotho, Africa, and Albertosaurus (albertosaurus) is found in Alberta, Canada.
Personal names are used in titles to honor the merits of outstanding scientists. English names Dinosaur researchers Mantel and Buckland included the names Megalosaurus bucklandi and Iguanodon mantelli. The name of the American paleontologist who discovered previously unknown lizards, Othniel Charles Marsh, is imprinted in the name of the small gazelle dinosaur Othniel, and the surname of the German lizard researcher Janensch is the name of the giant dinosaur Janenschia. Janensch himself immortalized the name of the director of the Berlin Museum of Natural History, Brank, by giving the largest giant dinosaur the name Brachiosaurus brancai (brachiosaurus brancai) - Brank's long-armed lizard. The full two-part name is used mainly in scientific works. In other cases, they are usually limited to the species name. Of the translated Latin names, only a few came into use, for example, armored lizard instead of panoplosaurus. When translated literally from Latin, names often turn out to be unreadable. Therefore, they usually prefer to use original names - many of them, such as dinosaur, brontosaurus or diplodocus, have already become familiar.
Where were dinosaurs found?

Australia

Who are called dinosaurs?
Dinosaurs are just one group of lizards or reptiles that lived in the Mesozoic - the era of average life on Earth. At the same time, other groups of reptiles lived with them, for example, flying and crocodile-like lizards, snake-necked and flat-toothed, fish-like and scaly lizards, as well as reptile-like mammals. The range of differences between dinosaurs was so great that family ties between them are difficult to establish. They could be the size of a cat or chicken, or they could reach the size of huge whales. Some of them walked on all fours, while others ran on their hind legs.
Among them were dexterous hunters and bloodthirsty predators, but there were also harmless herbivores. But one most important feature, common to all their species, immediately catches the eye: they were all terrestrial animals! Their limbs were located at the bottom of the body, and not on the sides, like most reptiles. Therefore, dinosaurs can also be called running lizards.

Family tree of reptiles and their descendants

Where did dinosaurs come from?
The first terrestrial vertebrates - ancient reptiles or ancient lizards - appeared over 300 mil. years ago. Unlike amphibians, they laid eggs not in water, but on land. The hard shell protected the large egg with a large yolk from drying out. What hatched from the egg was no longer a larva, but a fully formed animal.
These first lizard-sized land animals were the ancestors of all reptiles. Very soon, specific groups of animals appeared among them, adapted to various biological environmental conditions: predatory and herbivorous, slow crawling and fast running, forest and swamp.
At least six different groups of lizards and lizards can be distinguished. One of them includes crocodile-like thecodonts (root tooth lizards) ranging from one to two meters in length. Being predators, they hunted insects, frogs and small lizards, and some of them learned to take an upright position and run quickly on their hind legs. The new method of movement gave them a great advantage over other groups of lizards, which, like their ancient predecessors, moved on four legs located on the sides. These animals, the fastest among the thecodonts, are considered the ancestors of dinosaurs.

Lizard Euparkeria (root tooth)

How many species do we know?
To date, over 10,000 dinosaur remains have been found: individual bones and entire skeletons, skulls and teeth, eggs and excrement, fossilized footprints and other imprints. All the information about dinosaurs that scientists now have was obtained by studying these remains.
Over the 150-year history of studying fossils, paleontologists have been able to identify and describe over 500 different species of dinosaurs. Information about new discoveries is constantly being received. But it also happens that someone finds fossils and presents them as a new species, but then it turns out that they belong to an already known species, and the new name has to be abandoned. It also happens that a male and a female or a young and an adult animal of the same species are mistaken for different species.
Some of the 500 known species are so closely related to each other that they are combined into one family. Thus, nine species of horned dinosaurs from North America and North and East Africa are included in the family of brachiosaurs (long-armed lizards). Giant dinosaurs form over forty families.
The most numerous groups include carnivorous dinosaurs, numbering over 150 families, and bird-footed dinosaurs running on two limbs, forming 65 families.
The smallest group in terms of the number of species is apparently the group of spiny dinosaurs, where only eleven families are known so far.
When did the first dinosaurs appear?

Flora during the Triassic period

The era of dinosaurs began in the mid-Triassic, 230 million years ago. At that time, the modern continents were shifted and formed a single whole. The climate was hot and dry, and therefore vast areas of land resembled a desert. Ferns and horsetails grew in the damp lowlands in river valleys and along the ocean coasts, and tree ferns, conifers and ginkgo trees grew in the forests. The fauna in these regions was represented, along with insects and frogs, by numerous lizards: herbivorous and beak-nosed lizards, turtles and flying lizards, reptiles similar to lizards, crocodiles and mammals.
The first typical representatives of dinosaurs of that time were medium-sized bipedal predators (theropods), such as Chalticosaurus and Coelophysis. Larger and increasingly quadrupedal herbivorous dinosaurs, such as Plateosaurus, soon appeared. And finally, at the end of the Triassic, the first small bipedal herbivores (ornithopods), in particular Lesothosaurus, arose.
When did the largest dinosaurs live?

Flora during the Jurassic period

The Jurassic period began ca. 190 million years ago and ended 135 million years ago. Then huge predatory dinosaurs appeared, such as Allosaurus, and their giant herbivorous relatives, such as Apatosaurus. The first birds and flying lizards took to the air, and marine reptiles swam in the seas. Conifers and cycads were abundant and widespread. In the list below, the names of dinosaurs are given without specifying the group to which the genus belongs. 1 - Apatosaurus; 2 - Archeopteryx (primitive bird); 3 - Allosaurus; 4 - Camptosaurus; 5 - Neocalamites (primitive plants); 6 - Ichthyosaurs (marine reptiles); 7 - Stegosaurus; 8 - Plesiosaurus (marine reptile); 9 - Rhamphorhynchus (flying lizard); 10 - Pterodactylus (flying lizard); 11 - Williamsonia (bennettite); 12 - Araucaria (coniferous); 13 - Dilophosaurus; 14 - Cycadeoidea (bennettite); 15 - Ornitholestes; 16 - Compsognathus; 17 - Matonia (fern).

During the Jurassic period, 210-145 million years ago, the continents gradually moved apart, and shallow seas formed between them. The climate became humid and warm, and vast areas were covered with lush vegetation, especially diverse forests. Favorable environmental conditions contributed to the unprecedented flourishing of the world of dinosaurs: numerous new species arose that spread throughout the Earth. Of the living creatures on land, dinosaurs now dominated everywhere, and not other lizards.
At the same time, the evolution of numerous species of giant herbivorous dinosaurs took place. Huge land animals appeared, the largest ever to exist on Earth. Brachiosaurus, Apatosaurus, Diplodocus, Super-, Ultra- and Seismosaurus all lived during the Late Jurassic period. Small gazelles and larger beaked dinosaurs led a group lifestyle. Then came the amazing spiny dinosaurs. Along with smaller nimble predatory dinosaurs, such as Compsognathus and Archeopteryx, giants lived at this time - Allosaurus and Ceratosaurus, which, thanks to their powerful jaws, could cope with large herbivorous animals.
When did the last dinosaurs live?

Flora at the beginning of the Cretaceous period

During the Cretaceous period, 145-65 million years ago, the continents moved apart more and more, the seas between them became wider and deeper, and the climate became a little cooler. This led to the emergence of regions with rich flora, in which new changes took place. Flowering plants appeared, including broad-leaved trees such as magnolia and plane trees. They adapted better to new climatic conditions and eventually conquered the entire earth.
Dinosaurs also underwent various changes. Predatory dinosaurs became less and less common; only a few species were able to survive and continue their development. Spiny dinosaurs went completely extinct. They were replaced by armored ones, and then by horned ones. Along with the beaked dinosaur, a large number of duck-billed dinosaurs appeared.
Thanks to such richness and diversity of animals, giant predators like the Tyrannosaurus rex had no shortage of food. There were many smaller predatory dinosaurs with different specializations. Some of them were helped to hunt by impressive claws on the front and hind limbs, others, similar to ostriches, had developed forelimbs with which they grabbed small animals, others had no teeth and feasted on eggs, destroying nests.
However, serious changes that took place on earth at the end of the Cretaceous period led to the gradual extinction of all types of dinosaurs.
What are the distinctive features of giant dinosaurs?
Giant dinosaurs were the largest animals on Earth throughout history.
history. They were 10-20 times heavier than an elephant, the largest of them.
existing land animals. Only blue whale by weight and length
comparable to these extinct giants. With such a huge body weight for
to move on land they needed four legs and very massive
bones. Their limbs, especially the front ones, had a stocky shape, and all
five toes were brought together to form a stable foot. This reminds
an elephant's foot, for which they were nicknamed "elephant's foot" dinosaurs. Their scientific
sauropod name. That is, “lizard foot” dinosaurs.
Another distinguishing feature, one of a kind, was the very
Long neck. It was only half the length of the entire animal and
resembled the boom of a crane, capable of rising high and extending far into
side. And the bone structure, for all its strength, was extraordinary
easy.
How are giant dinosaurs different from each other?

Brachiosaurus (long-armed lizard), the largest giant weighing more than 80
tons, could not be confused with anyone. It had extended front
limbs. Therefore, his back formed a smooth descending line,
turning into the tail. The head with powerful teeth sat on a long neck on
height from 12 to 16 meters. The ultrasaurus was similar to him. True, he
known only from isolated bones and may have been even larger. U
All other dinosaur species had significantly shorter forelimbs.
Compared to Brachiosaurus, Camarasaurus (a rock lizard) had a neck
in short, and the body, head and teeth were just as powerful and strong. More
Dicraeosaurus (a curved lizard) looked proportional, and also had
short neck.
Most other dinosaur species had long necks. The greatest, almost
they reached nine meters in length in Mamenchisaurus (the lizard from Mamenchi) and
Barosaurus (heavy lizard). Owner of the longest tail (15 meters)
there was diplodocus (double beam). Thanks to this and its total length (27
meters) he was superior to all other dinosaurs known by complete
skeletons. With a modest weight - only 10 tons! - he also had the most “elegant”
appearance Supersaurus and Seismosaurus (seismic lizard), from which so far have been found
only a few bones, apparently, were similar to Diplodocus, but in length
reached 30 and 40 meters.
What did giant dinosaurs eat?
So far, no remains of stomach or mouth contents have been found.
such dinosaurs. One can only speculate what kind of plants they are
preferred to eat. During the Late Jurassic period, when most people lived
giant dinosaurs, the plant world was presented first
araucaria, as well as ferns, cycads, ginkgo and
coniferous trees.
Taking into account parameters such as neck length, body size and especially jaw size
and teeth, one can get an idea of ​​how these giants ate.
For example, large long-legged and long-necked species such as Brachiosaurus,
was accessible except for trees. Lighter ones, like diplodocus, could even
stand on your hind legs. But their thin pin-shaped teeth were
suitable only for eating ferns and stripping leaves from branches, while
while Kamatosaurus could bite and grind with its powerful teeth
whole shrubs and tree cores.
The teeth of giant dinosaurs were not adapted for chewing food.
So that their muscular stomach can grind pieces of plants, they
They swallowed stones the size of plums and even apples.
Previously, it was assumed that massive animals were constantly in the water and
fed on aquatic and underwater vegetation. It was believed that the dental apparatus
brachiosaurus, diplodocus and other dinosaurs served as gills,
holding food in the mouth and allowing water to flow out. The argument in favor of this
served as the location of the nasal openings of the highest point of the head: gigantic
dinosaurs could, like crocodiles or hippos, lie in water and breathe,
without raising his head. Only occasionally did they go onto land, mainly for
egg laying However, today there is no doubt that these dinosaurs could
They ran well and obtained their food mainly on land.
One can only wonder how, with such a small head and primitive
the structure of the jaws and teeth they managed to provide for their huge body
sufficient food. Apparently the animals spend most of the day
I had to chew.
Enemies of giant dinosaurs.

Judging by the footprints, some species of giant dinosaurs led a herd lifestyle. This provided protection primarily for young animals, since at this time large animals had already appeared, for example carnosaurs: Allosaurus, Ceratosaurus and Megalosaurus. The giant lizards could defend themselves against them only with their long tail, with which they delivered powerful blows, using it as a whip. This is confirmed by fossilized bones, on which there are often traces of healed wounds, most likely received from similar blows. It was dangerous for a predatory dinosaur to fall within the range of such a tail.
Which dinosaur was the largest predator?
Among the first dinosaur finds in England was a fragment of a lower jaw with several teeth. Apparently, it belonged to a huge predatory lizard, which was later dubbed the Megalosaurus (giant lizard). Since no other parts of the body could be found, it was impossible to get an accurate idea of ​​the body shape and size of the animal. It was believed that the lizard walked on four legs. Over the years, many other fossilized remains have been excavated, but a complete skeleton has never been discovered. Only after making a comparison with other predatory dinosaurs (carnosaurs), the researchers came to the conclusion that Megalosaurus also ran on its hind legs, its length reached 9 meters and it weighed a ton.
It was possible to reconstruct the Allosaurus (another lizard) with greater accuracy. Over 60 of his skeletons of various sizes have been found in America. The largest allosaurs reached a length of 11-12 meters and weighed from 1 to 2 tons. Their prey, of course, included giant herbivorous dinosaurs, which is confirmed by the found piece of an Apatosaurus tail with deep bite marks and knocked out Allosaurus teeth.

Tyrannosaurs attacking a herd of Triceratops

Even larger, in all likelihood, were two species that lived 80 million years later in the Cretaceous period, namely: TYRANNOSAURUS (tyrant lizard) from North America and TARBOSAURUS (terrifying lizard) from Mongolia. Although the skeletons are not completely preserved (most often the tail is missing), it is assumed that their length reached 14-15 meters, height 6 meters, and body weight reached 5-6 tons. The heads were also impressive: the Tarbosaurus skull was 1.45 meters long, and the largest Tyrannosaurus skull was 1.37 meters long. The dagger-shaped teeth, protruding 15 cm, were so powerful that they could hold an actively resisting animal. But it is still unknown whether these giants could really pursue prey or were too massive for that. Perhaps they ate carrion or the remains of the prey of smaller predators, which they had no trouble driving away. The dinosaur's forelimbs were surprisingly short and weak, with only two fingers. And a huge finger with a claw 80 cm long was discovered in a Tercinosaurus (sickle-shaped lizard). But whether this finger was the only one and what size the entire animal reached is unknown.
The 12-meter SPINOSAUROUS (spiny lizard) also had an impressive appearance. Along his back, the skin was stretched in the form of a sail 1.8 meters high. Perhaps this served him to scare away rivals and competitors, or perhaps it served as a heat exchanger between the body and the environment.
How did small carnivorous dinosaurs hunt?

Comparison of skeletons

Along with the giant predators, a type of small predatory dinosaur of lightweight proportions also appeared - a lizard with hollow bones, or CELUROSAUROUS. These dinosaurs also walked on long hind legs, but ran twice as fast
faster at a speed of 30-40 km/h. At the same time, their body and tail formed a horizontal line, and the neck was held vertically in an S-shaped position. The head was more proportionate to the entire figure, and the jaws were strewn with many narrow teeth. The forelimbs and hands were half as long as the hind limbs. Their sharp, tenacious claws were ideal for grabbing prey. Coelurosaurs hunted small animals, insects and lizards, and sometimes, perhaps, even young animals of their own species. Apparently, they also got some from the prey of large carnosaurs. Already in the Triassic there were many species of these small predatory dinosaurs, for example, the Galticosaurus (an agile lizard) 5 meters long, found in southern Germany and Thuringia.
Later, in the Jurassic period, even more slender long-armed and long-tailed animals appeared. Most often, the back half of their tail was rigid, like a fixed balancer. A nimble and evasive ORNITHOLEST (bird hunter) found in the North. America, reached a length of 2 meters. Compsognathus (elegant jaw) is considered the smallest species - it was the size of a chicken.
Does the ancient bird belong to small predatory dinosaurs?

In 1860, a sensation occurred: in southern Germany, an imprint of a typical bird feather was found in a layer of Jurassic sandstone. Did birds really live at the same time as the giant and the smallest dinosaurs in the Mesozoic era? After all, scientists of that time believed that birds appeared only at the end of the era of dinosaurs. Almost immediately, two complete skeletons were discovered with clear imprints of all plumage, including the characteristic feathered wings. The asymmetrical shape of the individual feathers and their arrangement on the wing were exactly the same as those of modern birds, which undoubtedly indicated that the fossil bird Archeopteryx (ancient wing) was capable of flight. True, the skeleton itself was completely different from that of a bird. It has a long tail, like a dinosaur's, but lacks the short tail of a bird. There are real teeth in the jaws, but no toothless bird beak. There are three free-standing fingers with claws protruding from the front of the wings. There are ribs on the neck and in the abdominal area, separate pelvic bones - everything is like a small predatory dinosaur. However, there is no powerful sternum, no rigid elements of the dorsal spine, no large pelvis, like in birds! Only individual bones and joints resemble those of a bird in shape.
If there were no feathers, then, based on the structure of the bones, the found skeleton would have been classified as a small carnivorous dinosaur. This, however, is what happened with two other finds of this ancient bird, where the imprints of the plumage were poorly distinguishable. For many years they were kept in a collection of materials related to dinosaurs until it was determined that they were specimens of Archeopteryx. So has the existing classification really turned out to be wrong? Perhaps they were too hasty in classifying this species as birds? Wouldn't it be better to place the ancient bird between these two groups?
Indeed, the ancient bird occupies an intermediate position in the evolutionary transformation of a hollow-bone dinosaur (coelurosaur) into a common bird. In the process of this development there were no big leaps or steps that would allow us to say: up to this point these were indisputably lizards, reptiles, and then - just as indisputably birds. It is also necessary to take into account that changes in individual parts of the body do not occur simultaneously: one part undergoes changes earlier, and the other later. This can also be seen on an ancient bird: feathers and wings are clearly avian features, and teeth and tail, on the contrary, unite it with reptiles. In the course of evolutionary changes, there are no sharp boundaries between the categories "coelurosaur" and "bird". The distinctions were made by man out of a desire to “put things in order” and create a harmonious classification of animals.
150 million years ago, ancient birds were of little concern about whether they were predatory dinosaurs or birds and how they should behave. By flapping their wings vigorously, they could take off and fly a short distance, although in flight they may have mostly just been gliding. Their prey were insects and small lizards.
Why do bird lizards have such big eyes?
The eyes and brain of a two-meter bird-lizard (saurornithoid) were unusual
large, almost like an eagle and an owl. Directed forward, such eyes
allowed him to track prey, accurately determining its location, apparently even at night. Quickly and deftly he discovered and caught
nocturnal mouse-like mammals. If the victim managed to hide, he
reached her with his heavily extended forelimbs even from
dense thickets or cracks in stones and rocks. For such sophisticated
In order to hunt, bird lizards also needed a special brain. He was there at six
times more than that of a modern crocodile.
Some researchers suggest that avian lizards and related species
they looked like birds: it is possible that their body was covered with feathers.
What do we know about ostrich dinosaurs?

With the exception of the long forelimbs and tail, the slender figures of these long-legged predators were very reminiscent of an ostrich or emu. Researchers reflected this similarity in the names of these dinosaurs: ornithomimus, STRUTHIOMIMUS, DROMICEIOMIUS, and GALLIMIMUS, which means “bird-like,” “ostrich-like,” “emu-like,” and “chicken-like.” Like large running birds, they could move quickly, faster than any other dinosaur - perhaps at speeds in excess of 50 km/h. They had no teeth, but apparently had a horny beak. However, we do not know whether they ate like birds. Did you eat insects and lizards, crabs and snails, or dig up the eggs of other lizards with your forelimbs? Or maybe they were generally herbivores and plucked leaves and branches, fruits and seeds? How did they grab food - with their forelimbs or beaks?
This and much more remains unsolved. Did they lead a herd lifestyle? Did you raise your offspring? Did they lay eggs or were they viviparous? The large pelvic cavity makes the latter assumption quite likely, but this is not a sufficient argument.
How big were the birdlegs?
All species of the second main group of dinosaurs - ornithischians (ornithischians) - were herbivores. But even among them, already in the Triassic, the first species of small animals were known that moved easily and quickly on two legs. Outwardly, they were similar to small predatory dinosaurs, but differed significantly from them in individual elements of their body structure.
Thus, the structure of the bones of the hind limbs was very similar to birds, so they were called bird-footed dinosaurs (ornithopods). Of course, they had the jaws of a herbivore, with tightly packed, faceted teeth, which they used to bite and chew leaves and stems. There were no teeth in the front part of the muzzle, and the jaw bones were covered by a horny beak. Subsequently, among the bird-footed dinosaurs their own giants appeared, twelve meters in length and weighing up to five tons. However, the first types were small and light, only one or two meters long. These include LESOTOSAUROUS (a lizard from Lesotho, in South Africa). It had long hind limbs with four toes. There were five short fingers on the front ones, which served as support, as well as for cleaning and searching for food. But most often the forestosaurus tore off leaves, branches and buds with its beak. Before swallowing, he bit them into pieces and chewed them thoroughly. When meeting with a predatory dinosaur, he fled for his life.
Soon new, larger species appeared. A notable feature of them, especially males, was their elongated fangs, which could hardly protect them from predatory dinosaurs - they were most likely used in the fight against rivals. This group was called heterodontosaurs.
How fast did gazelles run?
These were the fastest runners among dinosaurs. Scientists believe that on their “bird” legs they could reach speeds of up to 45 km/h. Apparently, this type of herbivores could successfully live at any time; its representatives are found throughout almost the entire Mesozoic era. At one time, gazelle dinosaurs ranging from one to four meters in length occupied in nature approximately the same place as is now occupied by medium-sized herbivores - from gazelles and antelopes, goats and deer to kangaroos. Like modern animals, they lived in herds.
They had a convenient horny beak for plucking plants. Thanks to the cheeks and cheek pouches, crushed food did not fall out of the mouth from the side. A typical representative of the gazelle dinosaur family was HYPSYLOPHODON (high-crested tooth). It was medium in size, from one and a half to two and a half meters in length, and lived during the Early Cretaceous era in Europe and North America.
The largest species was DRIOSAUR (oak lizard), over four meters long, and the smallest species was Nanosaurus (dwarf lizard), whose length did not exceed one meter.
Which beaked dinosaur is the most famous?
Bird-footed dinosaurs are called beak-nosed dinosaurs, the tip of which is covered with a wide, beak-like horny shield. It was very easy to pluck leaves with such a beak; it sharpened itself and constantly grew. The teeth were arranged in a row close to each other, forming a continuous surface, which made it possible to grind and chew food well.
The most typical species among these dinosaurs, the most famous and most frequently encountered, was the Iguanodon; see IGUANODONTS
Other widespread species include Camptosaurus (the curved lizard), named for its curved femur, and Tenontosaurus (the tendon lizard), which had ossified tendons that were stiff along the vertebral column of the back in all beaked lizards. Ouranosaurus (monitor lizard) had long processes on its dorsal vertebrae. It is not yet known whether they served as a support for his skin sail or for a hump similar to a camel's.
What are the distinctive features of duck-billed dinosaurs?

Corythosaurus group

Most duck-billed dinosaurs (hadrosaurs), of which more than 20 species are known, are distinguished by unusual bone formations on the head. In all other respects they are very similar to each other. Compared to their ancestors, the beaked dinosaurs, their beaks and teeth underwent further specialization. Over 1,000 small faceted teeth formed so-called batteries, so that food was crushed and chewed with file-like surfaces. The long tongue pushed plant food between these batteries into such a position that they were easy to chew. The outside of the mouth had cheeks and protected pouches.
The shape of the beak varied significantly between species - apparently, this depended on the different foods that one or another species preferred. The beak was similar to a duck's only in width, but it was harder, rather short, and there were teeth in the back of the jaw. In addition, it was not used in water, but for plucking and breaking off plants on land.

Fat-headed dinosaurs

Prenocephalic skull

There are many different assumptions about the purpose of the strange bone formations on the head. It is believed, for example, that they served as a nose, protected from overheating, served as an instrument for making sounds, or simply were an identifying mark for animals of their species. But since in males this growth was large in size and, perhaps, had a bright color, and in females it was small or completely absent, it hardly performed a vital function. It probably played a major role in the circulation of individuals of the same species (for example, when males fought for a female), like horns, inflatable larynx sacs, or colored combs on the heads of modern animals.
All these features indicate that duck-billed dinosaurs were very sociable animals and there was a certain hierarchy in their community or herd. Young animals occupied a special position in it and when the herd moved from place to place, they walked behind adult animals. As excavations have shown, females also laid their nests not alone, but in colonies. And the cubs, having hatched, remained in the nest for a long time under the protection of the female.
What did dinosaur skin look like?

Hard areas and elastic skin folds are clearly visible.

Skin is one of those parts of the body that does not turn into fossils and is not preserved for centuries. However, researchers were still lucky enough to find several of her prints. For example, an anatosaurus (duck lizard) was discovered. He died in a sandstorm and was buried under dry sand. The anatosaur's skin was smooth, dry and durable, with small raised areas of thicker horny skin standing out between its soft folds. Small bone plates were placed under these thickenings in the skin.
The ancestors of dinosaurs and their relatives, crocodiles, already had similar plates. It can be assumed that this type of skin was widespread among dinosaurs. In armored lizards, the bone plates are most developed. Their thickness reached 5 cm; they were located close to each other on top and on the sides of the body, forming a strong but flexible shell. It was covered with a layer of horny skin, creating a pattern similar to a tiled mosaic. On pointed or curved bony plates, horny skin enhanced these shapes, creating thick pointed horns or tubercles.
Apparently, the skin of dinosaurs resembled in its structure the skin of three groups of modern reptiles - turtles, crocodiles and beaked animals. However, it is impossible to say whether it was a scaly covering or skin like a snake.
It is also completely unknown what color the skin of dinosaurs was and what pattern it had. All color images are nothing more than the assumptions of researchers or the figment of the imagination of artists.
Skin print of a giant dinosaur. Hard areas and elastic skin folds are clearly visible.
Did dinosaurs require two brains?

Stegosaurus skeleton

More than a century ago, the American paleontologist Othniel Marsh, who first examined the complete skeleton of a giant dinosaur, stated with amazement: “The very small size of the head and brain suggests that the reptile was a stupid and slow animal...”. This opinion is so ingrained that even in everyday life the word “dinosaur” has become synonymous with antiquity and stupidity. However, in relation to many species of these animals, such an assessment is unfair: just remember the agility and dexterity of small predatory dinosaurs or the sociability of duck-billed lizards.
The carnivorous saurornithoid dinosaur had a fairly large brain, almost the same as that of mammals or birds. The recesses of the brain cavities of the skull indicate that the areas of the brain responsible for vision, smell, or complex types of movement, such as balancing, tactile and grasping functions, were quite well defined and reached large sizes.
Judging by the shape of the brain cavity of the skull, duck-billed dinosaurs also had good vision, hearing and smell. It was these feelings that were especially necessary for herbivorous lizards that do not have a shell in order to promptly recognize the enemy.
The smallest brains compared to body size were found in armored and spiny dinosaurs. The elephant-sized Stegosaurus had a brain only the size of a walnut! Was this really enough? In the femoral region of the spine there was another, larger cavity for the nerve center. Could this thickening of the spinal cord represent a second brain, as some researchers claim? Of course not. It was just an ordinary control center for the nerve pathways of the back of the body and tail. In most vertebrates with long tails, the spinal cord has a noticeable thickening in this place. And in stegosaurs, the tail was not just huge, longer than the entire body, but also performed a vital function - it served as a weapon of defense. In order to accurately control all the muscles of the tail during a targeted strike, a sufficiently developed nervous system was needed at the beginning of the tail.
However, the real brain is only the one contained in the skull. And apparently, such a brain was quite enough for the dinosaur, serenely grazing under the protection of its formidable spines, because spiny dinosaurs existed for many millions of years.
How fast did dinosaurs run?

Speed ​​characteristics of various dinosaurs

Throughout the entire era of dinosaurs, among both carnivorous and herbivorous bird-footed dinosaurs, there were species that were distinguished by a particularly proportional structure and moved only on their hind limbs. So, for example, CELOPHIS, who lived in the Triassic, was one of the fastest among the first dinosaurs. He was slender and light: with a three-meter length, he weighed only about 30 kilograms. Some of the last dinosaurs, who lived at the end of the Cretaceous period, 150 million years later than Coelophis, were no less slender and fast, for example the ostrich dinosaur (picture above). But how can one draw any conclusions about the speed of movement of animals that have long since become extinct?
What should we proceed from here? Three circumstances must be taken into account: firstly, the length of the animals’ legs - it can be easily determined from the bones found; secondly, body weight - it is calculated approximately; thirdly, the length of the step and the type of walking and running - they can be determined by the structure of the body and the fossilized footprints of dinosaurs. To more clearly imagine the running speed of dinosaurs, you can compare them with the “fast walkers” among modern vertebrates: racing horses and greyhounds, gazelles and cheetahs, hares and kangaroos, ostriches and California running cuckoos. The champions here are the cheetah and some species of gazelles, capable of reaching speeds of up to 100 km/h, that is, medium-sized animals with a body weight of about 50 kilograms. Lighter and more massive animals run slower.
What did dinosaur eggs look like?
Dinosaurs laid eggs. Given that they were reptiles, this was assumed even before their eggs were discovered. It was also clear that in size they could not be larger than the hole in the pelvis of the females through which they had to pass. But what exactly these eggs were, scientists were able to find out only on the basis of the first finds.
For the first time, the fossilized remains of dinosaur eggs were found back in the last century in the south of France, but it was impossible to determine their size or identity from them. The first clutches of eggs were discovered in 1923 in the Gobi Desert. Moreover, these were eggs of not just one, but different types of dinosaurs.
But in the south of France, where they were discovered for the first time, further excavations also turned out to be very fruitful. Several hundred eggs were found here, buried under a layer of sand and silt during a flood some 70 million years ago. Among them, ten different types of eggs were identified. The largest were round in shape, 24 cm long and with a capacity of three to three and a half liters. One partially preserved nest, one meter wide and 0.70 meters deep, contained 12 such eggs. Perhaps they belonged to the giant dinosaur Hypselosaurus.

found in the Gobi Desert. Dinosaur egg

How did dinosaurs take care of their offspring?
Reports of the most amazing discoveries of dinosaur nests began to arrive in 1978 from the American state of Montana. An entire colony has been preserved here - more than a dozen nests of duck-billed dinosaurs. Each nesting hole reached two meters in width and one in depth. In one of the nests there were only crushed egg shells, in the other there were young animals from half a meter to two meters long. At the time of emergence from an egg about 20 cm long, the young animal could be no longer than 30-35 cm.
This means that the cubs were in the nest for quite a long time (they crushed the shell) under the protection of the mother who fed them. This duck-billed dinosaur was named Maiasaura (mother lizard). The females weighed at least two tons and could hardly hatch eggs. Most likely, the plant material used to build the nest, when rotting, released heat sufficient for the development of the embryo in the egg.
There was a nesting site for gazelle dinosaurs nearby, which had apparently been in use for many years. Ten meter-long nests contained 24 oblong eggs. But the hatched baby gazelle dinosaurs did not remain in the nest, but immediately left it and gathered nearby in groups of young animals. Thus, dinosaurs exhibited nestling and brood behavior among young animals that were cared for differently by females.
Did dinosaurs lead a herd life?
Findings of fossilized footprints and massive accumulations of bones provide evidence that some dinosaurs lived in herds. For a professional researcher, footprints can tell a lot about the behavior of animals.
In Texas, 20 pairs of giant dinosaur tracks were found in a layer of rocks. The tracks ran parallel, only a few of them intersected. They were of different sizes, therefore there were young animals in the herd that walked in the middle. A herd of duck-billed dinosaurs left their footprints on one of the rock slabs discovered in Canada. They walked in wide formation on the soft ground at that time. The young animals appeared to be at the back of the herd, as their tracks overlapped those of the older animals. To date, quite a few arguments have been accumulated in favor of the gregarious lifestyle of herbivorous dinosaurs.
But some species of small predatory dinosaurs also stayed together. This is confirmed by nineteen identical tracks with an average step length, located close to each other on the same site. This means that these animals also hunted in herds. Large, heavy carnivorous dinosaurs have so far only seen single tracks.
How long did dinosaurs live?

Duck-billed dinosaurs: female with babies

The simplest method of determining age by tree rings, which reflect seasonal changes in the rate of tissue growth, does not apply to dinosaurs. In those days, environmental conditions were the same throughout the year, and animals could grow evenly. Tree rings did not form on trees or on the teeth or bones of dinosaurs. Therefore, we can only speculate about the age of dinosaurs. Immediately after birth, the animals certainly grew quickly, especially the chicks, which were fed and protected by the female during the first weeks of life. Brood animals were more independent at an early age, but grew more slowly. Once young dinosaurs reached two-thirds the size of an adult animal, they became capable of procreation. Now their growth slowed down, but did not stop until the end of their lives. It is believed that giant dinosaurs required 40 to 50 years to reach sexual maturity, and they could live up to 200 or even 300 years. The life expectancy of small species was, in all likelihood, less - from one to two decades.
When did dinosaurs go extinct?
Usually the answer to this question is short and unambiguous: 65 million years ago at the end of the Cretaceous period, at the end of the Mesozoic era. For 150 million years, constantly changing species of dinosaurs reigned supreme on our planet, and then suddenly disappeared from the face of the Earth in a short period of time. No traces have been found in Tertiary sediments.
True, not all species and groups of dinosaurs even survived to the end of the Cretaceous period. Already 120 million years earlier, in the middle of the era of dinosaurs, for example, the last ancestors of giant dinosaurs disappeared. And spiny dinosaurs died out 60 million years earlier than other groups. But their place was taken by others - thick-headed and horned dinosaurs.
New species constantly appeared, while a significant part of the old ones disappeared. Most dinosaur species only existed for about two to ten million years at most.

Triceratops, extinct 65 million years ago

Why did dinosaurs become extinct?
Ever since dinosaurs were discovered, researchers have always wondered why they disappeared so completely at the end of the Cretaceous period. More than a hundred hypotheses were put forward on this score, but almost all of them turned out to be untenable.
It has often been overlooked that, unlike dinosaurs, other groups of animals - crocodiles, lizards, snakes, turtles, birds and mammals - survived this critical time. Why were they an exception?
On the other hand, at the same time as land dinosaurs, sea lizards, ammonites and small marine animals, as well as land plants, disappeared. This means that they were influenced by the same reasons! The hypotheses about the global flood are untenable - after all, marine animals also died out, and many land animals were not affected at all. The hypothesis about the extermination of dinosaurs by primitive man, who, as has already been proven, appeared only 60 million years later, also has no basis.
Internal reasons associated with the dinosaurs themselves, such as their enormous growth and clumsiness, cannot be considered sufficient, since both the smallest and the fastest dinosaurs became extinct. The assumptions that carnivorous dinosaurs destroyed herbivores and then themselves died of starvation, or that all the dinosaurs were eaten by small mammals, also do not stand up to criticism. But then why didn’t they touch the reptiles that have survived to this day? One of the newest hypotheses puts forward as the main cause a sudden catastrophe that occurred on Earth - a collision with a huge meteorite. According to this hypothesis, a celestial body with a diameter of ten kilometers fell to Earth. From the impact, such an amount of dust rose up that the sky over the entire Earth darkened for many months. Plants that needed sunlight died, followed by herbivores, and then predators. A cold snap occurred as the sun's rays no longer reached
earth's surface. Then warming came again, when the upper layers of the air warmed up again. And even if some species managed to survive the catastrophe, they still died as a result of its consequences, which lasted for years and centuries. If this catastrophe, the likelihood of which can be judged by a number of signs, was really so destructive, then the sudden appearance of all dinosaurs is quite understandable. But it is completely incomprehensible how such sensitive representatives of the animal world as birds could survive!
A more convincing and justified point of view is that the extinction of dinosaurs did not occur suddenly, but continued over a fairly long crisis period. Living conditions gradually deteriorated for those animals that were adapted to the previously uniform warm and humid climate, to the rich flora and fauna. Constant movements of continents and seas have led to significant climate changes. As the earth's crust shifted and the ocean floor expanded, more and more shallow areas became more sparsely vegetated land. Warm conditions without any temperature changes gave way to colder nights and harsher winters.
Many dinosaurs were deprived of their usual feeding conditions when food was abundant everywhere. Cold nights and winters adversely affected the breeding of offspring. The babies grew more slowly, certain types of dinosaurs became increasingly rare and gradually began to die out, in some regions earlier, in others later. The crisis period continued on land for at least five million years. There was a process of extinction of dinosaurs and flying lizards. Along with them, entire species of plants and mammals also disappeared, but they were already being replaced by new ones.
A meteorite strike or some other sudden catastrophe could only significantly disrupt the living conditions of animals and plants and cause the process of gradual extinction of many of their species, but not destroy them immediately. This point of view provides a more logical explanation for the mysterious disappearance of dinosaurs.

Classification
Squad
Lizard-pelvic (Saurischia)

Suborder sauropods (Sauropoda) Illustrated Encyclopedic Dictionary