How much did Tyrannosaurus rex weigh? Other ancient reptiles
At the end of 1905, newspapermen wrote excitedly about the bones of a prehistoric monster that paleontologists had unearthed in the badlands of Montana. The New York Times presented the "tyrant lizard" as the most fearsome fighting animal in history. More than a hundred years have passed, and Tyrannosaurus rex continues to excite the imagination of the public and paleontologists.
More than 12 meters from snout to tail, dozens of sharp teeth the size of a railroad spike: the 66-million-year-old Tyrannosaurus rex is not just one of the prehistoric predators, but an icon of ancient horror. He is so charismatic that a routine paleontological discussion can be blown out of proportion.
This happened last year: a group of paleontologists presented their views on the fact that T. rex was not so much a hunter as a scavenger. The media presented this as a sensation, which infuriated paleontologists. In fact, the issue has long been resolved: enough evidence has been collected that suggests that the dinosaur not only ran after prey, but also did not disdain carrion.
What is discussed is what role living and dead animals played in his diet. What is especially unfortunate is that this not the most important problem hid other, more interesting aspects from the public.
For example, the origin of dinosaurs remains a mystery. Researchers cannot yet determine how the kings of the Cretaceous period (145-66 million years ago) grew from tiny dinosaurs of the Jurassic period (201-145 million years ago). What T. rex looked like as a juvenile is heavily debated, with suspicions that some specimens described decades ago as distinct species are actually juveniles of other species.
Even the appearance of the tyrannosaurus remains controversial: many argue that the giant body was covered with fluff and feathers, and not scales. The scandalous question of why the animal had such a massive head and legs, but tiny forelimbs, has not gone away.
Fortunately, there is enough material. “There are plenty of fossils,” reports Stephen Brusatte from the University of Edinburgh (UK). “It’s rare that so many good specimens remain from one species.” With T. rex, we can ask questions about how it grew, what it ate, how it moved; We can’t ask that for many other dinosaurs.”
In the first decades after Henry Fairfield Osborn named and described Tyrannosaurus rex, paleontologists saw it as the culmination of the rise of land carnivores. Therefore, T. rex was considered a descendant of Allosaurus, a 9-meter predator that lived more than 80 million years earlier. Both of them, along with other carnivorous giants, were grouped into the taxon Carnosauria, with T. rex considered the last and largest representative of the ferocious family.
But in the 1990s, a more rigorous research method, cladistic analysis, began to be used, and the evolutionary relationships between dinosaur groups were reconsidered. It turned out that the ancestors of T. rex were small furry creatures that lived in the shadow of Allosaurus and other predators of the Jurassic period.
According to new thinking, T. rex and its closest relatives (Tyrannosauridae) represent the top branch of a large evolutionary "bush" called Tyrannosauroidea, which arose about 165 million years ago. Among the earliest members of this group is Stokesosaurus clevelandi, a 2-3 m long bipedal predator that lived about 150 million years ago.
Little is known about this creature, but other early tyrannosauroids provide evidence: Stokesosaurus most likely had a long, low skull and thin forelimbs. In the Jurassic size hierarchy, early tyrannosauroids were at the very bottom. “By today's standards, they were at the level of lap dogs,” Mr. Brusatte jokes.
How did it happen that over time, tyrannosaurs ended up at the top of the food chain in North America and Asia? So far history is silent about this. A very small number of rocks aged 90-145 million years have been found (it was during this period that tyrannosaurs crushed their competitors), so the biodiversity of those times has been reconstructed very fragmentarily. Nothing can be said about changes in sea level and climate in general, which could lead to the dominance of this particular group.
Recently, the main attention of paleontologists studying this time interval has been focused on China. In 2009, Peter Makovicki of the Field Museum in Chicago (USA) and his colleagues described a long-snouted tyrannosaurus called Xiongguanlong baimoensis, which was found in western China in rocks formed 100-125 million years ago.
The animal reached almost four meters in length - a solid step forward compared to the tyrannosaurs of the Jurassic period. And in 2012, Xu Xing from the Institute of Vertebrate Paleontology and Paleoanthropology (PRC) and his colleagues described a 9-meter tyrannosaurus named Yutyrannus huali, which belongs to the same era.
Perhaps this was a decisive time interval when tyrannosaurs and allosaurs fought to the death for the same ecological niches. In rocks from northern China, Mr. Brusatte and his colleagues found the 5-6 m long allosaurus Shaochilong maortuensis, which lived about 90 million years ago, that is, the size of the competitors was approximately the same. But exactly when and why the tyrannosaurs won remains unknown.
It’s just not interesting to portray our hero. He's definitely fighting with someone! (Fig. ameeeeba.)
The situation is similar with what T. rex looked like in its youth. At the center of the debate is Nanotyrannus lancensis, found in the same North American sediments as T. rex, and possibly growing 6 m in length. At first it was considered a separate species, but some researchers see it as a juvenile T. rex.
According to Thomas Holtz Jr. of the University of Maryland, College Park, USA, the differences between N. lancensis and T. rex are reminiscent of the differences between juveniles and adults of other tyrannosaur species. It should be noted that all nanotyranus samples seem to be “minor” to him.
Lawrence Whitmer of Ohio University (USA) doesn't think so. In 2010, he and his colleague Ryan Ridgley, using a CT scan of a skull from the Cleveland Museum of Natural History (the holotype of N. lancensis), discovered unusual depressions in the braincase and paranasal sinuses at the back of the skull, where air sacs were located during the dinosaur's life. These formations make this specimen very different from T. rex, which makes it possible to classify the specimen as a different species.
In addition to the above, Peter Larson, president of the Black Hills Geological Research Institute (USA), argues that nanotyranus teeth have too fine serrations and are too tightly packed. He also points out differences in the anatomy of the glenoid cavity of the scapula and the openings in the skull.
However, critics noted that some of this information was gleaned from the analysis of fossils that have not yet been described in the scientific literature. Moreover, scientists may even lose one of the key samples of nanotyranus, because in November it will be auctioned in New York.
The hype did its job: it is estimated that the specimen will bring the owner $9 million. Most paleontologists simply refuse to take into account such fossils that are not freely available in a respected museum. Is it possible that some private owner will have the audacity to rob science?
“In this situation, there is only one thing left to do - to again advise in a tired voice to look for other samples,” Mr. Whitmer says. For Nanotyranus to be definitively recognized as a separate species, either a juvenile T. rex would need to be found, more similar to the adult than Nanotyranus, or the remains of an animal that was undoubtedly an adult Nanotyranus and clearly different from T. rex. But Mr. Whitmer is pessimistic about the chances of ending the debate: "I don't know how much data it will take to convince everyone." T. rex is too charismatic, and views on it have already been formed, so paleontologists will not simply abandon their usual opinion.
Another example of this is the controversy regarding the appearance of our hero. From generation to generation it was depicted as covered with scales like modern reptiles, although they are very distant relatives. But in the last two decades, specimens of many groups of dinosaurs with feathers and fur have been discovered in China. Some of them belong to species closely related to T. rex.
In 2004, Mr. Xu described a small early tyrannosaurus, Dilong paradoxus, with fiber impressions around the tail, jaw and other parts of the body. Is it really a down coat? The giant Y. huali was also feathered. The feathers of tyrannosaurs were not the same as those of modern birds, but their primitive predecessors. According to Mr. Xu, they served primarily as decoration and were later used for thermal insulation. It is possible that T. rex also proudly wore some kind of proto-feathers.
No, no one wants to say that T. rex was like a chicken. We are talking about thin fibers, a kind of hairs - for example, on the muzzle.
Since not a single skin print of T. rex has been found, these are all just assumptions, which is what skeptics use. Thomas Carr from Carthage College (USA) refers to skin prints of species close to T. rex that have not yet been described in the scientific literature. y, on which scales are supposedly clearly visible. Well, it's possible that early tyrannosauroids had feathers, but the subgroup of tyrannosaurids that includes T. rex evolved to abandon them in favor of scales.
The question of feathers is very important not only for artists who no longer know how to depict the ancient miracle of Yudo. If there were feathers, then we can assume some kind of mating games and talk about how the tyrannosaurus regulated its body temperature.
Another secret is the giant’s small hands. They are so short that you can’t even reach your mouth with them. Paleontologists have everything in order with their imagination, and over a hundred years the most exotic hypotheses have been put forward: they say, it was convenient to squeeze a partner in your arms during mating or climb steep slopes. Gradually, the opinion became established that the forelimbs were a rudiment. Countless cartoonists to this day depict tyrannosaurs, which are haunted by one embarrassment after another on this basis.
But Sarah Birch from Ohio University (USA) believes that such jokes are unfair. She studied the muscles of crocodiles and the only living descendants of dinosaurs - birds. If T. rex's arms were indeed useless vestiges, they would not have had any significant muscles, but the fossils show evidence that quite a bit of muscle was attached to the bones.
So T. rex used its arms. But for what? Grabbed and held certain objects (for example, prey), as all other theropods did?
Mr. Holtz has a different idea. Estimates of muscle strength suggest that these short arms were still relatively weak tools. And since specimens were found with healed fractures of the forelimbs, the scientist concludes that they did not play a vital role. One thing remains: short arms could be useful during mating games. Who knows, what if they were shrouded in colorful feathers?..
Tyrannosaurus (lat. Tyrannosaurus - “tyrant lizard) is a monotypic genus of predatory dinosaurs.
A group of coelurosaurs of the theropod suborder with the only valid species Tyrannosaurus rex (Latin rex - “king”).Habitat: about 67-65.5 million years ago in the last century of the Cretaceous period - Maastrichtian.
Habitat: western part of North America, which was then the island of Laramidia.
The last of the lizard-hipped dinosaurs that lived before the cataclysm that ended the era of dinosaurs.
Appearance
A bipedal predator with a massive skull balanced by a long, stiff and heavy tail. The front paws were very small, but very strong, and had two toes with large claws.
The largest species of its family, one of the largest representatives of theropods and the largest land predators in the entire history of the Earth.
Dimensions
The largest known complete skeleton, FMNH PR2081 "Sue", reaches a length of 12.3 meters and a hip height of 4 meters. The weight of this individual during life could reach 9.5 tons.
But fragments were found that belonged to even larger tyrannosaurs. Gregory S. Paul estimates the length of specimen UCMP 118742 (maxillary bone 81 cm long) to be approximately 13.6 meters, the height to the hips to be 4.4 meters, and the mass to be 12 tons.
Lifestyle
Tyrannosaurus was the largest carnivore in its ecosystem and was most likely an apex predator - hunting hadrosaurs, ceratopsians and possibly sauropods. However, some researchers suggest that it fed mainly on carrion. Most scientists believe that Tyrannosaurus could both hunt and feed on carrion (it was an opportunistic predator).
Body type
Tyrannosaurus's neck, like other theropods, was S-shaped, short and muscular, supporting its massive head. The forelimbs had only two fingers with claws and a small metacarpal bone - a vestige of the third finger. The hind limbs were the longest relative to the body of any theropod.
The spine is composed of 10 cervical, 12 thoracic, five sacral and about 40 caudal vertebrae. The tail was heavy and long, serving as a balancer to balance the massive head and heavy body. Many of the bones of the skeleton were hollow, which greatly reduced their weight while maintaining almost the same strength.
Scull
The largest complete Tyrannosaurus rex skull found reaches a length of about one and a half meters. The skull of Tyrannosaurus rex was different from the skulls of large non-tyrannosaurid theropods. Its back was wide and its snout was narrow, thanks to which the lizard had highly developed binocular vision, allowing the brain to form a reliable model of space, estimating distances and sizes. Presumably, this indicates a predatory lifestyle.
The nasal and some other bones of the skull were combined, preventing foreign objects from getting between them. The skull bones were air-filled and had paranasal sinuses, like other non-avian dinosaurs, which made them lighter and more flexible. These properties indicate a tendency in tyrannosaurids to increase their bite force, which significantly exceeded the bite force of all non-tyrannosaurid theropods in these lizards.
The end of the upper jaw was U-shaped, whereas in most non-tyrannosaurids it was V-shaped. This shape made it possible to increase the volume of tissue that the tyrannosaurus tore out of the victim’s body in one bite, and also increased the pressure of the lizard’s front teeth.
Tyrannosaurus rex has well-pronounced heterodontism, the difference in teeth in form and function.
The teeth on the front side of the upper jaw have a D-shaped cross-section, fit tightly together, are equipped with a chisel-shaped blade, reinforcing ridges and are curved inward. Thanks to this, the risk of breaking a tooth during biting and dragging the victim was reduced.
Other teeth are stronger and more massive, more banana-shaped than dagger-shaped, wider apart and have reinforcing ridges.
The largest tooth found reached a height of 30 centimeters along with the root, being the largest carnivorous dinosaur teeth ever found.
Tyrannosaurids did not have lips; their teeth remained open, like modern crocodiles. On the snout there were large scales with pressure receptors.
Bite force
Research by paleontologists Carl Bates and Peter Falkingham in 2012 suggested that the bite force of the Tyrannosaurus rex was the greatest of any land animal that has ever lived on Earth. Based on the tooth marks on the bones of Triceratops, the rear teeth of an adult Tyrannosaurus could have compressed with a force of 35 to 37 kilonewtons, which is 15 times the greatest measured bite force of an African lion, three and a half times the bite force of an Australian saltwater crocodile, and seven times that of an Australian saltwater crocodile. Allosaurus bite force.
Lifespan
The smallest specimen found, LACM 28471 ("Jordan theropod") had a body mass of 30 kilograms, while the largest, FMNH PR2081 "Sue", weighed more than 5,400 kilograms. Histology of the T. rex bones showed that "Jordan theropod" was two years old at the time of death, and "Sue" was 28 years old. Thus, the maximum lifespan of tyrannosaurs probably reached 30 years.
Paleontologists believe that tyrannosaurs “lived fast and died young” because they reproduced quickly and lived too dangerous a life.
Posture
The initial reconstructions of scientists, who depicted the tyrannosaurus, like other bipedal lizards, in the “three-legged tripod” pose, turned out to be incorrect. Lizards of this type of posture moved, holding their torso, tail and head almost in one line, horizontal with respect to the ground. The tail was straightened and constantly curved to the sides in opposition to the movements of the head.
Forelegs
The forelimbs of the tyrannosaurus are extremely small in relation to the size of the body, reaching only one meter in length. However, their bones have large areas for muscle attachment, indicating great strength.
Scientists believe that they could serve to get up from a resting position, to hold the sexual partner during mating, and also to hold the victim trying to escape.
The exceptionally thick, non-porous surface layer of the bones of these limbs indicates the ability to withstand significant loads. The biceps brachii muscle of an adult tyrannosaurus was capable of lifting a load of 200 kilograms. The brachialis muscle worked in parallel with the biceps muscle, increasing elbow flexion. The T. rex's biceps were three and a half times stronger than a human's. The massiveness of the foreleg bones, muscular strength and limited range of motion suggest a special system of the tyrannosaurus's forelimbs, developed to firmly hold prey making desperate efforts to escape.
Leather and feathers
Scientists believe that T. rex had feathers on at least some parts of its body. This version is based on the presence of feathers in related smaller species.
Feathers in tyrannosauroids were first discovered in the small dinosaur Dilong paradoxus from the famous Yixian Formation of China. Its fossilized skeleton, like those of many other theropods from the same formation, was bordered by a layer of filamentous structures usually considered proto-feathering. Larger tyrannosauroids had fossilized scales, so scientists concluded that the number of feathers decreased with age, because. immature individuals were feathered to preserve heat, and by adulthood, large animals had only scales. However, subsequent discoveries showed that even some of the larger tyrannosauroids had feathers on most of their bodies.
It is possible that the number of feathers and the nature of the cover could change in tyrannosauroids depending on the time of year, changes in the size of lizards, climate changes or other factors.
Thermoregulation
Most likely, the tyrannosaurus was warm-blooded, as it led a very active lifestyle. This is supported by the high growth rate of tyrannosaurs, similar to that of mammals and birds. Growth charts show that their growth stopped during immaturity, unlike most other vertebrates.
Scientists analyzed the ratio of oxygen isotopes in the bones of tyrannosaurs and found that the temperature of the spine and tibia differed by no more than 4-5 °C, which indicates the ability of the tyrannosaurus to maintain a constant internal body temperature thanks to a metabolism average between the metabolisms of cold-blooded reptiles and warm-blooded ones mammals.
Even if Tyrannosaurus rex maintained a constant body temperature, this does not mean that it was completely warm-blooded, since such thermoregulation could be explained by a developed form of mesothermy observed in living leatherback sea turtles.
Movement
Most of the Tyrannosaurus's mass was removed from its center of gravity; it could reduce this distance by arching its back and tail and pressing its head and limbs towards its body. Most likely, the tyrannosaurus turned rather slowly; it could make a 45° turn in 1-2 seconds.
Tyrannosaurus's maximum speed:
Average estimates are around 39.6 km/h or 11 m/s.
The lowest estimate is from 18 km/h or 5 m/s.
72 km/h or 20 m/s.
Many tracks of large theropods walking have been found, but none have been found left behind by running. This may mean that tyrannosaurs were not capable of running. However, other experts noted the greater development of the muscles of the Tyrannosaurus's legs compared to any modern animal, which gives them reason to believe that it could reach speeds of 40-70 kilometers per hour.
For such a massive animal, falling while running quickly could result in fatal injuries. However, modern giraffes can reach speeds of up to 50 km/h, risking breaking a leg or falling to death not only in the wild, but also in a zoo. It is likely that, in case of need, the tyrannosaurus also exposed itself to this risk.
In a 2007 study, a computer model for measuring running speed estimated T. rex's maximum speed at 29 km/h (8 m/s). By comparison, a sprinter can reach a top speed of 43 km/h (12 m/s). The model estimated the maximum speed of a three-kilogram (possibly juvenile) Compsognathus specimen at 64 km/h (17.8 m/s).
Brain and sense organs
Coelurosaurids had enhanced sensory abilities. This is evidenced by the fast and well-coordinated movements of the pupils and head, the ability to detect low-frequency sounds, thanks to which the tyrannosaurus detected prey at long distances, as well as an excellent sense of smell.
It is also believed that the Tyrannosaurus rex had very acute vision. Its binocular range was 55 degrees - more than that of a modern hawk. The visual acuity of a tyrannosaurus was 13 times higher than that of a human, respectively, exceeding the visual acuity of an eagle, which is only 3.6 times higher than that of a human. All this allowed the tyrannosaurus to distinguish objects at a distance of 6 kilometers, while a person can only recognize them at a distance of 1.6 kilometers.
Tyrannosaurus' increased depth perception may have been related to its prey. These included the armored dinosaur Ankylosaurus, the horned dinosaur Triceratops, and the duck-billed dinosaurs, which either ran away or camouflaged and hid.
Tyrannosaurus Rex had large olfactory bulbs and olfactory nerves relative to the size of its entire brain, allowing it to smell carrion over great distances. Tyrannosaurus's sense of smell is likely comparable to that of modern vultures.
The very long cochlea of Tyrannosaurus rex is unusual for theropods. The length of the cochlea is associated with hearing acuity, which shows how important hearing was in his behavior. Studies have shown that Tyrannosaurus rex was best at picking up low-frequency sounds.
The eye sockets of the tyrannosaurus were located so that the gaze was directed forward; the lizard had good binocular vision - better than that of hawks. Horner noted that the lineage of tyrannosaurs showed a steady improvement in binocular vision, while scavengers did not require increased depth perception.
In the modern world, excellent stereoscopic vision is characteristic of fast-running predators.
Traces from the teeth of tyrannosaurs on the bones of Triceratops without signs of healing are quite common. Fossils exist that show smaller tyrannosaurids, possibly juvenile Tyrannosaurids, successfully hunting down larger Triceratops.
While studying the “Sue” specimen, Peter Larson found the fibula and caudal vertebrae fused after a fracture, as well as cracks in the facial bones and a tooth from another tyrannosaurus stuck in the cervical vertebrae. This may indicate aggressive behavior between tyrannosaurs. It is not known for certain whether tyrannosaurs were active cannibals or simply engaged in intraspecific struggle for territory or mating rights.
Further studies showed that the injuries to the facial bones, fibula and vertebrae were caused by an infectious disease.
The current view is that tyrannosaurs occupied different ecological niches depending on size and age, like modern crocodiles and monitor lizards.
Thus, newborn cubs most likely fed on small prey, and as they grew, they switched to larger and larger ones. Perhaps the largest tyrannosaurs hunted for carrion, taking prey from their smaller relatives.
Poisonous saliva
There is a hypothesis that the tyrannosaurus could kill the victim using its infected saliva. Rotten remains of meat could accumulate between the teeth of the Tyrannosaurus rex; the bite of the Tyrannosaurus rex infected the victim with harmful bacteria.
The tyrannosaurus probably tore pieces of meat from the carcass by shaking its head from side to side, as crocodiles do. In one bite, an adult tyrannosaurus could tear out a piece of meat weighing 70 kg from the victim’s body.
Paleoecology
The range of the Tyrannosaurus rex extended from Canada to Texas and New Mexico. In the northern regions of this range, Triceratops dominated among the herbivores, and in the southern regions, sauropods of the Alamosaurus species dominated. Remains of tyrannosaurs have been found in a variety of ecosystems, from inland landmass to wetlands and arid and semi-arid (arid and semi-arid) plains.
Several notable T. rex finds have been made in the Hell Creek Formation. During the Maastrichtian era, the area was subtropical, with a warm and humid climate. The flora is represented mainly by flowering plants; coniferous trees such as metasequoia and araucaria were also found. Tyrannosaurus shared habitat with Triceratops and the closely related Torosaurus, as well as the duck-billed Edmontosaurus, armored ankylosaur, pachycephalosaurus, thescelosaurus, and the theropods Ornithomimus and Troodon.
Another deposit of Tyrannosaurus rex remains is the Lance Formation of Wyoming. Millions of years ago it was a bayou ecosystem similar to the modern Gulf Coast. The fauna of this formation is very similar to that of Hell Creek, but the ornithomimus niche was occupied by Struthiomimus. A small representative of ceratopsians, Leptoceratops, also lived there.
In the southern regions of its range, the tyrannosaurus lived with the Alamosaurus, Torosaurus, Edmontosaurus, the representative of the ankylosaurs Glyptodontopelta and the giant pterosaur Quetzalcoatlus. It was dominated by semi-arid plains, where the Western Inland Sea formerly lay.
Tyrannosaurus is the largest predator dinosaur that lived in North America at the end of the Cretaceous period (68-65 million years ago).
Description of appearance
The Tyrannosaurus rex fully corresponded to its characteristics of being the largest. The body length was almost 13 meters, height could reach 3.5-4 m, and weight was almost 8 tons.
The T. rex skeleton consists of 299 bones, of which 58 are allocated to the skull. The spine contains 10 cervical, 12 thoracic, 5 sacral, 40 caudal vertebrae. The neck, like that of many other theropods, was S-shaped, but it was short and thick, which served as a device for holding a large head. Another feature of tyrannosaurs was hollow bones, which helped reduce the overall body mass without losing strength.
The shape of the skull was different from other theropods: it was wide at the back and narrowed at the front. Thanks to this, the dinosaur's eyes looked forward and not to the side. Consequently, T. rexes had developed binocular vision.
The forelimbs are small, with 2 active fingers. The hindquarters are strong and powerful with 3 toes. Theropods' tails were long and extremely heavy.
Due to the structural features of the skull, tyrannosaurs had a powerful bite. The teeth were different in shape. The D-shaped ones fit tightly together, were curved inward and had small serrations, and this reduced the risk of tearing out when biting and jerking.
The inner teeth were banana-shaped. Widely spaced, they enhanced the strength of the entire jaw.
The length of one tooth including the root, found among the remaining remains, is approximately 31 cm.
The running speed of the T. rex still causes heated debate, since the mass that the hind limb could withstand remains unknown. Some experts believe that tyrannosaurs had the most developed and voluminous leg muscles.
But studies conducted in 2002 found that the speed of theropods could have been no more than 40 km per hour. And studies in 2007 showed a figure of 29 km per hour.
Tyrannosaurus rex food
It is believed that T. rexes were carnivorous predators, but the studied remains do not allow us to give an exact answer to how they obtained food. There is a theory according to which tyrannosaurs cannot be considered ruthless and cold-blooded killers, since their only weapon was a powerful jaw. And the poorly developed forelimbs and huge body did not allow him to destroy everyone and everything.
There are 2 known versions describing the methods and types of nutrition of theropods.
Scavenger
This version is based on studies of the found remains of tyrannosaurs: most likely, they not only did not disdain the carcasses of their dead brothers, but also ate them with great pleasure. There are several facts in favor of this theory:
- Massive body, which weighed more than one ton, did not allow the T. rex to engage in long pursuits and tracking down prey.
- CT scan. Using a study of the restored dinosaur brain, it was possible to study in more detail the functionality and structural features of the “inner ear,” which is responsible not only for hearing. Tyrannosaurs had an “inner ear” that was different in structure from other dinosaurs, which were considered dexterous hunters.
- Vertebral studies. The giant lizard had some limitations in movement: maneuverability and agility were not its strong points.
- Teeth. The structure of T. rex teeth suggests that they are adapted for crushing and grinding bones, extracting large amounts of food from the remains, including bone marrow. As a rule, the teeth of dinosaurs that ate fresh meat were more fragile: after all, they simply ate the body.
- Slowness. The size of tyrannosaurs harmed their owner: if they fell, the lizard could damage or break ribs or legs. Slow reaction and clumsiness, short forelimbs and two fingers did not help the hunt.
Based on all the above facts, scientists came to the conclusion that the tyrannosaurus was a scavenger.
Hunter
The previous version with the T. rex being a scavenger has quite good justification, but some paleontologists are inclined to think that the giants were hunters. And the following facts speak in favor of this version:
- Powerful bite. His strength allowed the T. rex to break any bones.
- Herbivorous dinosaurs. It is possible that the main prey of theropods were torosaurs, triceratops, anatotitans and others. Due to its size, the giant lizard could not pursue its victims. Possessing binocular vision, Tyrannosaurus was presumably able to judge the distance between itself and its prey, attacking in one burst from an ambush. But, most likely, the choice fell on young or old and weakened dinosaurs.
The theory that the theropod was a hunter has one caveat: T. rexes still did not disdain the remains of dead dinosaurs.
It is known that tyrannosaurs were loners, hunting exclusively in their own territory.
But, for sure, there were clashes.
If one of them died, the giant ate the meat of the deceased relative.
It turns out that if the T. rex was not a pure scavenger.
It’s also a stretch to call him a hunter: he could still eat dead carcasses or take food from other dinosaurs.
Fortunately, his size allowed him to do this.
T. rex breeding
Adult theropods were loners. The territories in which they could hunt measured hundreds of km2.
When mating is necessary, the female calls the male with a characteristic roar. But even here everything was not easy. The courtship process took time and required effort.
Female tyrannosaurs were much larger and more aggressive than males.
In order to gain favor, the males had to bring the carcass of some pangolin as a treat.
The mating process itself was short-lived. After it, the male T. rex went in search of food or other females, and the fertilized female prepared to become a mother: she built a nest for laying eggs.
After a few months, the female theropod laid about 10-15 eggs.
Fossilized Tyrannosaurus Rex Eggs
But the nest was located directly on the ground, and this was extremely risky: after all, small predators could eat the laid offspring.
For the purpose of protection and protection, the female did not leave the eggs for 2 months.
After a couple of months, offspring hatched from the laid and carefully guarded eggs.
As a rule, only 3-4 cubs appeared from the entire brood.
This is explained by the fact that during the Late Cretaceous period, in which tyrannosaurs existed, the atmosphere was filled with gases due to volcanic activity.
They had a detrimental effect on the development of the embryo, destroying it from the inside. Thus, the T. rexes were already doomed to death.
History of finds
Fossils were first found in Hell Creek, Montana in 1900. The expedition was organized by the American Museum of Natural History and led by B. Brown.
The remains obtained during this expedition were described by Henry Osborne in 1905. Then he classified the tyrannosaurus as Dynamosaurus imperiosus.
A reconstructed specimen of a tyrannosaurus obtained by B. Brown in 1902-1905.
1902: Fossil remains of a partial skeleton and incomplete skull discovered ( AMNH 973), the bones were removed over three years.
Henry Osborne in 1905 described the fossil data as Tyrannosaurus rex, and then the first remains were recognized Tyrannosaurus rex.
1906: The New York Times publishes an article about the first T. rex.
A partial skeleton of huge bones from the hind limbs and pelvis was installed in the American Museum.
1908: B. Brown discovered an almost complete specimen with a skull. G. Osborne described it in 1912.
1915: The first reconstruction of a complete skeleton of a Tyrannosaurus rex appeared at the American Museum of Natural History, with one drawback: the arms of a T. rex replaced the three-fingered limbs of an Allosaurus.
1967: W. Mac Manis, archaeologist, University of Montana, discovered the skull. The copy was assigned a number MOR 008. Scattered bones of an adult lizard were also found.
1980: The “black beauty” was found. Black Beauty received its name due to the dark color of the remains. J. Baker discovered a large bone on the banks of a river in Alberta. The excavation of the entire T. rex lasted a whole year. The sample is displayed in Royal Tyrrell Museum in Drumheller, Alberta, Canada.
1988: Kathy Wankel, a farmer, found bones sticking out of the ground in the sediments of Hell Creek (an island in the Montana National Forest).
The specimen was not recovered until 1990 by a team at the Museum of the Rockies, led by Jack Horner.
It includes about half of the skeleton. It was here that complete theropod forelimbs were first discovered.
This sample was named "Wankel Rex" (MOR 555). He was about 18 years old at the time of his death. An adult dinosaur that has not reached its maximum size. These are the first fossils to show biological molecules in their bones.
1987: Tyrannosaurus, nicknamed Sten. Discovered by Stan Sakrison in Hardling County, South Dakota. Excavations were completed in 1992. The remains were initially thought to be those of a Triceratops.
Additional "Wall" bones were found in 1993 and 2003. The length of its body is 12 meters, the length of the skull is 1.3 m. Moreover, the T. rex had many pathologies: broken ribs, fused cervical vertebrae, holes in the back of the head from the teeth of relatives.
Real "Sue" skull
1990: Sue Hendrickson was lucky enough to discover the largest complete specimen of a Tyrannosaurus rex.
The remains are 73% complete. The length is 12.5 meters, the skull is 1.5 m.
1998-99: preparation and thorough cleaning of the found remains.
2000: the skeleton is completely mounted and presented to the public.
A study of "Sue" revealed that the individual was approximately 28 years old at the time of death. And it reached its maximum size by the age of 19.
1998: T. rex found " Bucky". It was discovered along with the bones of Edmontosaurus and Triceratops. Bucky is the first giant in whose bones a “fork” was discovered—fused collarbones in the shape of a “fork.”
Skeleton "Sue"
Its dimensions were: 29 cm wide and 14 cm high.
The “fork” is the link between dinosaurs and birds.
2010: Tyrannosaurus rex skeleton discovered " Tristan Otto". Carter County, Montana.
Excavations were completed in 2012, after which the bones were cleaned and processed over the course of 2 years.
49% were recovered with the skull intact.
The individual died at the age of 20. The body length was 12 m, height - 3.5 m, weight -7 tons.
2015: a copy of " Rees Rex". Hell Creek, northeastern Montana.
30% of the skeleton and a well-preserved skull were recovered, which is considered the most complete T. rex skull ever recovered.
T. rex (Tyrannosaurus Rex) is by far the most popular dinosaur that has lived on our planet. He became the hero of a huge number of books, films, television shows and even video games.
For a very long time, T-Rex was considered the most powerful carnivore that ever walked the Earth.
10 Little-Known Facts About T-Rex
1. Tyrannosaurus Rex Wasn't the Largest Carnivorous Dinosaur
Most people subconsciously believe that the North American Tyrannosaurus Rex, measuring 12 meters from head to tail and weighing up to 9 tons, was the largest carnivorous dinosaur that ever walked the planet. However, an interesting fact is that in ancient times there were two types of dinosaurs that were larger than T. rex - the South American Giganotosaurus, which weighed about nine tons and grew up to 14 meters long, and the North African Spinosaurus, which weighed more than 10 tons. Unfortunately, these theropods never had the opportunity to fight among themselves, since they lived in different times and in different lands, separated by thousands of miles and millions of years.
2. T-Rex's front legs weren't as tiny as many people assume.
One anatomical feature of Tyrannosaurus Rex that many people scoff at is its front legs, which appear disproportionately tiny compared to the rest of its massive body. But in fact, T. rex's front legs were more than 1 meter long and may have been capable of lifting up to 200 kg.
You will be interested to know that the most cartoonish - tiny front legs belong to the giant Carnotaurus. His arms looked like tiny bumps.
3. T-Rex had very bad breath.
Of course, most dinosaurs of the Mesozoic era did not have the ability to brush their teeth, and very few of them had teeth. Some experts believe that the remains of rotten meat, infected with bacteria, which were constantly present between the terrible teeth, made the T. rex bite poisonous. Such a bite would infect (and ultimately kill) the bitten victim. The problem is that this process would likely take days or weeks.
4. Female T-Rexes were larger than males.
We don't know for sure yet, but there is good reason to believe (based on the size of T. rex fossils found and the shape of their hips) that female T. rex outsized their males by 800 kg, which is a sign of sexual dimorphism.
For what? The most likely reason is that females of the species had to lay huge eggs, which is why evolution gave females such large hips, or perhaps females were simply more skilled hunters than males (as is the case with modern lions) and consumed more food.
5. The average lifespan of a T-Rex was about 30 years.
It is difficult to infer the lifespan of dinosaurs from their fossilized remains, but based on analysis of skeletal specimens found, paleontologists suggest that Tyrannosaurus Rex may have lived for up to 30 years. Since this dinosaur was at the top of the food chain of its range, its death was most likely due to old age, disease, or starvation, rather than from fights with predators. It was very rare for a tyrannosaurus to die from the teeth of another predator when it was too young and weak. (By the way, in parallel with T. Rex, Titanosaurs may have lived, whose weight exceeded 50 tons, their life expectancy was about 100 years!)
6. T-Rex hunted and picked up carrion
For years, paleontologists have debated whether T. rex was a brutal killer or a mere scavenger—that is, did it actively hunt or pick up the carcasses of dinosaurs that died of old age or disease? Today these contradictions seem quite strange, since Tyrannosaurus Rex could use these two methods of food simultaneously, like any massive predatory animal that constantly wanted to satisfy its hunger.
7. T. rex subspecies Hatchlings may have been covered in feathers
We all know that dinosaurs are the ancestors of birds, and that some carnivorous dinosaurs (especially raptors) were covered in feathers. Consequently, some paleontologists believe that all tyrannosaurs, including T. rex, must have been covered in feathers at some point in their life cycle, most likely when they first hatched from their eggs. This conclusion is supported by the discovery of feathered Asian tyrannosaurs such as Dilong and the nearly equal T. rex Yutyrannus.
8. Tyrannosaurus Rex, most of all loved to hunt Triceratops
If you think that Mayweather vs. Pacquiao was the most brutal boxing fight, then you are sorely mistaken. Imagine a hungry eight-ton Tyrannosaurus Rex attacking a five-ton Triceratops! Such an unthinkable fight could certainly have happened, since both of these dinosaurs lived in the late Cretaceous period in the lands of North America. Of course, the average T. Rex would prefer to take care of a sick or recently hatched Triceratops. But if he was too hungry, large individuals also became his victims.
Back in 1996, a team of scientists from Stanford University who studied the skull of this dinosaur determined that T. rex bit its prey with a force of 700 to 1400 kg. per square inch, with the same force that the largest modern alligators bite. More detailed studies of the skulls showed that its bite force was in the range of 2,300 kilograms per square inch. (By comparison, the average adult can bite with about 80 lbs. per inch of force.) The powerful jaws of T. Rex could even bite through the horns of Ceratopsus itself!
10. Tyrannosaurus Rex was originally named Manospondylus
When famed paleontologist Edward Pinker Cope unearthed the first fossilized skeleton of T. rex, in 1892, he called the find "Manospondylus gigax - Greek" (giant slender vertebrae). After further impressive fossil exploration, it was then-president of the American Museum of Natural History, Henry Fairfield Osborne, who gave the immortal name Tyrannosaurus Rex, the "tyrant lizard king."
Tyrannosaurus Rex was one of the largest carnivorous dinosaurs that ever lived on Earth. Everything about this ferocious predator, with its thick, heavy skull and 1.2-meter jaw, was designed for maximum bone crushing efficiency.
Paleontologists were shocked when they discovered an almost complete skeleton of a Tyrannosaurus rex in 1902. Scientists knew they had found one of the largest carnivorous predators of all time. His head was the size of an adult. Tyrannosaurus's body can stretch across the entire width of a tennis court. Up to seven tons of muscle and other tissue filled its strong skeleton.
Tyrannosaurus was created for hunting
As evidence confirming the killer's reputation, a pelvic bone was found covered with Tyrannosaurus rex bite marks, including a large piece of bone missing. This means the predator could bite through any part of its prey with its 20cm, cone-shaped, razor-sharp teeth. Imagine a tooth the size of a banana? In a fossilized piece of Tyrannosaurus dung, upon analysis, several Edmontosaurus bones were discovered - further evidence of the claim. Scientists believe that this powerful predator can eat up to 230 kilograms of meat in one bite.
Fossil evidence shows that Tyrannosaurus was about 12 meters long and 4.6 to 6 meters tall. Its strong thighs and long, powerful tail helped it move quickly; Tyrannosaurus Rex could run short distances at speeds of up to 45 kilometers per hour, which is very close to the speed of a human Olympian. Given its enormous size, the T. rex skull was easy to construct. It had wide holes and hollow bones.
Tyrannosaurus lived in forested river valleys in North America during the late Cretaceous period.
The photograph shows a Tyrannosaurus Rex skull in a museum.