To establish how and whether dinosaurs would survive today, one has to explore the conditions they lived in before they went extinct. The first dinosaurs appeared between two hundred and forty-seven and two hundred and forty million years ago, yet some people talk about dinosaurs as if they were around in the recent past.
Some dinosaurs, in the form of birds, still survive today and are doing very well. The dinosaurs that lived millions of years ago would not survive today because they occupied niches in very different ecosystems and aren’t adapted for our colder, less oxygenated, and much-altered environment.
To put things into perspective, the earliest homo sapiens remains are only around three hundred thousand years old. Even so, scientists don’t describe them as anatomically modern humans because they bore marked differences to us. Modern human beings have not even been around for half a million years.
So what were the conditions on Earth eons ago when dinosaurs thrived? And if dinosaurs existed today, how would they survive? Let’s find out…
How Would Dinosaurs Survive Today?
To answer this question, one has to consider several different factors that made it possible for dinosaurs to evolve and live on Earth in the first place. One also has to look at the size and nature of various dinosaurs, what they ate, what their ecosystems looked like, and the type of climates they lived in.
Some dinosaurs were relatively small and might still be capable of surviving in some parts of the world today, but many others were giants that modern ecosystems could not sustain. Today’s humans would not recognize the planet occupied by dinosaurs because the continents, and therefore many seas and oceans, had not yet formed. Plantlife was very different, and so was the atmosphere.
Dinosaurs are an incredibly diverse group of animals that did not all exist at the same time. Periods of many millions of years separated certain types of dinosaurs from others. The Mesozoic Era in which they lived lasted one hundred and eighty million years, and by the time humans appeared, they had been extinct for sixty-five million years. So the question must be not only how dinosaurs would survive today but which dinosaurs could survive today.
Scientists are still not clear about why dinosaurs became extinct, and the theory that they all died as the result of a meteorite strike is not necessarily true. By the Cretaceous Period, the third and last period of the Mesozoic Era, many dinosaurs which lived in the earlier Triassic and Jurassic Periods were already extinct. Profound Earth changes can occur in one hundred and eighty million years.
What Distinguishes Dinosaurs From Other Reptiles?
To establish how dinosaurs would survive today, it is first necessary to identify which ones we mean. Some small dinosaurs might be capable of surviving today, but the vast majority would not.
The name dinosaur comes from Dinosauria, a combination of Greek words meaning “terrible lizard”. It was first suggested by the British biologist and paleontologist Richard Owen in 1842 when he noticed that certain fossils had skeletal similarities, unlike those of other saurians.
One of these was five fused vertebrae at the sacrum, a part of the hip area. Since then, paleontologists realized with increasing fossil discoveries that dinosaurs are a very diverse and distinct group of animals.
Contrary to popular belief, not all ancient reptiles were dinosaurs. The word “dinosaur” is a scientific term that only applies to certain reptiles with a specific set of features related to their hips. Dinosauria is a clade that includes more than one thousand species that walked the Earth across a period of around one hundred and seventy-five million years. New species are being discovered all the time.
Dinosaurs were essentially land-dwellers, but some could have waded into rivers and lakes to eat. They are all linked by a common ancestry that allowed them to inherit a unique set of features.
Modern birds are the only living dinosaurs.
Dinosaurs Occupied Complex Ecosystems
While all dinosaurs lived in the Mesozoic Era, not all living creatures from this Era were dinosaurs. Insects, amphibians, and mammals were also around with the dinosaurs. All dinosaurs were terrestrial, which means they did not live in rivers, lakes, or oceans. Reptiles that inhabited ancient seas are not dinosaurs.
Dinosaurs walked with their legs perpendicular to their bodies like birds, not out to the side like crocodiles. Some walked on four legs and were herbivores, while others walked on two legs and were carnivores. Whether bipedal or quadrupedal, their stance was upright, and their legs’ position supported their weight better.
All dinosaurs had two holes in the skull behind the eyes that provided for the attachment of facial muscles. This feature distinguishes them from other animals. Some dinosaurs, like certain theropods, had feathers.
Dinosaurs Were Intelligent
Dinosaurs are often portrayed as big and stupid, but this was not necessarily true. Scientists have estimated that most dinosaurs were about as intelligent as modern-day reptiles, while some were much smarter.
The dinosaurs related to birds, the dromaeosaurids such as Velociraptor, were intelligent, as were the troodontids. Predatory dinosaurs were generally more intelligent than their herbivorous counterparts because it is harder to hunt animals than plants. Tyrannosaurus Rex had a particularly large brain when compared to other dinosaur predators of the same size.
Their intelligence level would not prevent them from surviving today.
Dinosaurs Had Very Different Metabolisms
According to an article in 2014 in the journal Science, Dinosaurs were not warm-blooded or cold-blooded but fell somewhere in the middle. However, there is a long-running, complex scientific debate about dinosaur physiology, with some scientists saying they were warm-blooded and others arguing they were cold-blooded.
If they were cold-blooded, their chances of surviving a much cooler modern Earth are slim. If they ate only tough, woody, coniferous plants, their chances of getting sufficient nutrition from flowering plants are also unlikely. Vegetation in their day consisted of vast tracts of forests, cycads, and ferns that no longer exist.
Carnivorous dinosaurs would have to be able to eat a diet consisting mainly of mammals. Although there were mammals around in their day, they were small and unlikely to provide as much nutrition as other dinosaurs. Carnivorous dinosaurs ate a lot of herbivorous dinosaurs that were much bigger than themselves.
Scientists have discovered a significant downturn in most dinosaur populations around one hundred million years ago, except for two of the herbivores – the horned ceratopsians and the crested hadrosaurs. This was before the Chicxulub meteorite struck.
When Did Dinosaurs First Appear?
Dinosaurs lived in the Mesozoic Era, which is divided into three distinct periods: the Triassic Period, the Jurassic Period, and the Cretaceous Period. The Triassic is the oldest and is between two hundred and fifty-two and two hundred and one million years ago. It lasted for around fifty million years. In this period, all the continents were still a single landmass called Pangea. Much of it consisted of deserts, and it was relatively hot and dry with no polar ice caps.
Dinosaurs are reptiles and may have preferred hotter climates for thermoregulation purposes. They may have relied on their environment to keep their bodies at optimum temperature, moving into the Sun when they got too cold and seeking shade when they got too hot. Reptiles don’t lose water through their skins like mammals, and their kidneys also conserve water better than mammalian ones. Drier climates suited them.
The Triassic Period began after the worst extinction event in the Earth’s history, which occurred at the end of the Paleozoic Era. Scientists still don’t know what caused this Great Dying, which destroyed up to ninety percent of all species in some estimates. Plants and animals were affected by this event, and ecosystems had to begin anew in the Triassic Period. It is estimated that the planet took up to ten million years to recover.
It was in the warm, dry climates of the Triassic Period that the first dinosaurs evolved. Although Pangea was a single landmass, there were significant differences between plants in the north and the south. The plants were mainly conifers that formed enormous forests with trees up to thirty meters tall. The understory was also made up of coniferous shrubs and vines that are extinct. There were no grasses and flowering plants.
In drier areas, vast expanses of fern prairie took over from the forests, and the most common land vertebrate was a small, herbivorous mammal-like reptile called Lystrosaurus. Ancient amphibians called Temnospondyls that were four meters long, dominated freshwater rivers and lakes.
In the early Triassic Period, the mammal-like reptiles, called synapsids, dominated the land, but another group, the archosaurs, were co-inhabitants. As the middle of the Triassic Period came and went, the synapsids gave way to a wide range of archosaurs, and by the late Triassic, they dominated the land. The first dinosaurs appeared in the fossil record around two-hundred and forty million years ago and were small.
Archosaurs were not dinosaurs, and while they continued to dominate most of Pangea in the Triassic Period, dinosaurs started to diversify rapidly.
Triassic Period Dinosaurs
During the Triassic Period, dinosaurs were small, nimble, and primarily bipedal. The pseudosuchians, a group of reptiles that resembled crocodiles, were the top predators in this period. Examples of some Triassic dinosaurs are given in the table below, together with their estimated length in meters
|Eocursor||Herbivore, Ornithschian, 1 meter|
|Gojirasaurus||Carnivore, small therapod, 5,5 meters|
|Plateosaurus||Herbivorous, sauropod, 10 meters|
|Melanosaurus||Omnivorous, sauropod, 12 meters|
|Eoraptor||Carnivorous, small therapod, 1 meter|
|Coloradisaurus||Omnivorous, sauropod, 4 meters|
|Mussaurus||Herbivorous, sauropod, 3 meters|
|Liliensternus||Carnivorous, small therapod, 5 meters|
|Staurikosaurus||Carnivorous, small therapod, 2 meters|
|Chindesaurus||Carnivorous, small therapod, 4 meters|
Pangea began to break in two in a series of massive earthquakes and volcanic eruptions two hundred and one million years ago at the end of the Triassic Period. There was a mass extinction at the end of the Triassic, the cause of which is still unknown, but the dinosaurs survived, unlike many other large land animals.
Jurassic Period Dinosaurs
The Jurassic Period is a geological period of fifty-six million years that began after the Triassic Period and ended when the Cretaceous Period began. Pangea became two landmasses, Laurasia and Gondwana, although there were still some land bridges between them. Temperatures dropped slightly, but the Earth was still warmer than today because of the atmosphere’s high carbon dioxide levels.
Rainfall on land increased due to the formation of the large seas between the two continents. Ferns and horsetails proliferated over enormous tracts of land, and there were tall coniferous forests.
Below is a table showing some of the dinosaurs from the early, mid, and late Jurassic Period. This gives an idea of the wide variety of dinosaurs just from this period alone. Their length is expressed in meters.
|Early Jurassic||Sarcosaurus||Carnivorous, small theropod, 3 meters|
|Pantydraco||Herbivorous, sauropod, 3 meters|
|Vulcanodon||Herbivorous, sauropod, 6,5 meters|
|Lophostropheus||Carnivorous, large theropod, 6.2 meters|
|Anchisaurus||Herbivorous, sauropod, 2.0 meters|
|Ammosaurus||Herbivorous, sauropod, 5 meters|
|Kotasaurus||Herbivorous, sauropod, 9 meters|
|Middle Jurassic||Gasosaurus||Carnivorous, small theropod, 4 meters|
|Cetiosaurus||Herbivorous, sauropod, 18 meters|
|Eustreptospondylus||Carnivorous, large theropod, 7 meters|
|Amygdalodon||Herbivorous, sauropod, 15 meters|
|Megalosaurus||Carnivorous, large theropod, 9 meters|
|Sinraptor||Carnivorous, large theropod, 7.6 meters|
|Segisaurus||Carnivorous, small theropod, 1.5 meters|
|Late Jurassic||Diplodocus||Herbivorous, sauropod, 26 meters|
|Allosaurus||Carnivorous, large theropod, 12 meters|
|Archaeopteryx||Carnivorous, small theropod, 0.5 meters|
|Brachiosaurus||Herbivorous, sauropod, 30 meters|
|Juravenator||Carnivorous, small theropod, 0.8 meters|
|Apatosaurus||Herbivorous, sauropod, 21 meters|
|Camptosaurus||Herbivorous, euornithopod, 5 meters|
Brachiosaurus, Diplodocus, and Apatosaurus were herbivorous sauropods and some of the largest animals ever to have walked the Earth.
Cretaceous Period Dinosaurs
Dinosaurs flourished in the Cretaceous Period, between one hundred and forty-five and sixty-six million years ago. It is often called the “Age of the Dinosaurs”. Many of those most familiar to people come from this time. Flowering plants, and new kinds of dinosaurs called ceratopsians and pachycephalosaurids, first appeared in the Cretaceous Period.
The Cretaceous Period was the longest in the Mesozoic Era and lasted for around seventy-nine million years. The table below gives some examples of Cretaceous Period dinosaurs and their length.
|Aucasaurus||Carnivorous, large theropod, 5 meters|
|Argentinosaurus||Herbivorous,sauropod, 35 meters|
|Bambiraptor||Carnivorous, small theropod, 1 meter|
|Bactrosaurus||Herbivorous, euornithopod, 6 meters|
|Carnotaurus||Carnivorous, large theropod, 7.6 meters|
|Deinocheirus||Omnivorous, large theropod, 10 meters|
|Daspletosaurus||Carnivorous, large theropod, 9 meters|
|Hadrosaurus||Herbivorous, euornithopod, 9 meters|
|Indosuchus||Carnivorous, large therapod, 7 meters|
|Oviraptor||Omnivorous, small theropod, 2 meters|
|Parasaurolophus||Herbivorous, euornithopod, 11 meters|
|Pentaceratops||Herbivorous, ceratopsian, 6.8 meters|
|Styracosaurus||Herbivorous, ceratopsian, 5.5 meters|
|Telmatosaurus||Herbivorous, euornithopod, 5 meters|
|Triceratops||Herbivorous, ceratopsian, 9 meters|
|Tyrannosaurus||Carnivorous, large theropod, 12 meters|
In addition to the dinosaurs, more ancient birds arose, and avians were very diverse in the Cretaceous Period. They would have provided food for carnivorous dinosaurs. It was a time of massive change for all life and ended with a mass extinction event that the Chicxulub meteorite may have precipitated.
What Foods Did Dinosaurs Eat?
To ascertain how dinosaurs would survive today, one needs to look at the kinds of food they ate in their time. Dinosaurs did not exist in a vacuum. To so successful for so many millions of years, they had to fit into the larger ecosystems that existed back then. The climate, topography, and vegetation were very different from what they are today.
Cycads, ferns, club-mosses, horsetails, and whisk ferns lived in the understory of vast coniferous forests. Some of these plants still exist in a form that has changed little, but they are not as numerous. Gingko Biloba trees and the dawn redwood, which are still around today, date back to the Mesozoic Era when dinosaurs lived but are no longer widespread. Gingko was extinct in North America for more than one hundred and fifty thousand centuries.
The dawn redwood (Metasequoia glyptostroboides) was believed to be extinct until discovered growing in a remote valley in China. It is a deciduous conifer that has been dated back to the Cretaceous Period ninety million years ago. One explanation for the demise of dinosaurs in the Late Cretaceous is that the slow-growing seed plants that replaced the gymnosperms were not enough to feed giant herbivores such as sauropods.
Brontosaurs weighed as much as thirty tons, while brachiosaurs weighed more than fifty tons, and Seismosaurus was even bigger and may have weighed as much as ninety tons. Such gigantic animals would have to eat tons of vegetation a week if they were cold-blooded and even more if they were warm-blooded. An elephant only weighs six tons.
The flowering plants that eventually replaced conifers, cycads, and tree ferns as the dominant species were more resistant to extreme cold and drought, suggesting the occurrence of climate changes with greater variations in weather patterns. Grasslands replaced fern inhabited plains. Many of the plants of our time did not exist when the dinosaurs walked the Earth. This may preclude the survival of herbivorous dinosaurs today.
Those that lived before grasses evolved would not have teeth, jaws, and digestive systems adapted to eat grass. As we know from modern grazers, digesting grass requires specialized digestive arrangements to obtain the necessary nutrition.
If predatory dinosaurs were still alive today, they would have no difficulty hunting and killing prey, including modern mammals. However, they would not fit into current ecosystems and would likely destroy them before long. The giant herbivorous dinosaurs hunted by Tyrannosaurs are no more and had the body composition of reptiles with tough leathery skin and armor plating.
It is unlikely that dinosaurs the size of Tyrannosaurs could survive today on much smaller mammals like pigs and cows. It may have to consume them in large quantities, and they may not be as well suited to its digestive system. Perhaps the smaller theropods would have a better chance as they would need much less food.
Dinosaurs in these periods ate the leaves of pine trees and redwoods, ferns, moss, rushes, and cycads. As time went on and flowering and fruiting plants came into being in the later Mesozoic Era, they may have eaten these, but there is evidence that some of them did not adapt their diet. Grasses came much later, towards the end of the Cretaceous Period.
Sauropods could not chew and did not have grinding teeth and cheeks to keep food in their mouths. Their teeth were like pegs and were used to strip leaves from trees before swallowing them. They may have swallowed stones to help them digest their food. They could not eat grass.
Even those dinosaurs with grinding back teeth couldn’t chew like mammals because of their jaw structure. Mammals chew with their lower jaw moving in a sideways movement while dinosaurs side to side chewing movements resulted from the upper jaw expanding as the mouth closed.
Scientists have been able to ascertain what foods certain dinosaurs ate from fossilized dinosaur excrement, called coprolites, and the contents of their stomachs. Some of them, like the hadrosaur, ate berries, twigs, and tough plants, while an ankylosaur called Minmi ate seeds and leaves. They did find traces of grass in a coprolite from India that was sixty-six million years old.
Plant eaters evolved in several bursts, one in the Jurassic Period and another three in a period of eighty million years in the Cretaceous Period. Plants were also changing rapidly during the Mesozoic Era, which had started with mainly coniferous trees and ferns. Flowering plants arose in the Cretaceous period millions of years after the Triassic and Jurassic periods. However, dinosaur teeth did not necessarily evolve to accommodate plant evolution, and some of them, like the hadrosaurs, were still eating conifers even in the Late Cretaceous.
Hadrosaur teeth and digestive systems were designed to crush and dissolve tough oily pine needles and cones. The fact that many coniferous shrubs and vines from the Mesozoic Era are extinct suggests that there wouldn’t be enough coniferous plants to sustain dinosaurs today.
They may be able to survive in specific forest biomes on Earth, but the enormous quantities of plant material the gigantic animals would need are no longer available. Such dinosaurs would undoubtedly pose a threat to modern ecosystems, and their existence in significant numbers would not be sustainable.
Recent evidence suggests that some plant-eating dinosaurs in the Late Cretaceous Period may have had more complex diets that included insects, crabs, and other shellfish, which provided a vital protein source. Instead of being purely herbivores, they were omnivores.
What Was The Climate Like In The Days of The Dinosaurs?
The climate was likely mild, warmer, and more tropical than today, with less temperature variation between equatorial and polar latitudes. The weather over large portions of the continents was dry. The seas were higher in the Mesozoic Era, and there were more deserts and less marshland.
The climate did vary in the three different periods of this Era, but generally, it was an age of gigantism for both plants and animals. Many scientists agree that a meteorite caused the mass extinction at the end of the Cretaceous Period. Still, there was evidence of a decline in dinosaur populations several million years before this event.
The Earth in the Mesozoic Era was an alien world, some six degrees Celsius warmer than today, with dense forests extending towards the poles from the equator. Coral reefs grew further south and north, and warm summers had only daylight hours for almost a month.
The atmospheric humidity was much higher due to the higher global temperatures, and it rained more over the oceans than on land. These are what scientists call greenhouse conditions. They alternated with hothouse extremes that occurred as a result of surface lava flows (magmatic events).
Pangea broke up in the Jurassic Period opening up the Atlantic and Indian oceans. Tectonic plate activity was high as the continents were splitting apart, and there were significant magmatic events.
The Deccan Traps in India were spewing out vast quantities of lava before the meteorite hit and afterward, causing climate changes that some scientists believe accelerated the dinosaurs’ demise. Volcanism leads ultimately to global cooling because the dust and ash in the atmosphere block out the Sun’s warmth and light. Dinosaurs accustomed to balmy conditions in the tropics would be unable to survive the cold temperatures caused by volcanic winters.
Atmospheric carbon dioxide was seven times higher than the pre-industrial level, and the average oxygen level was one hundred and thirty times higher than the current level. There was thus far more oxygen and carbon dioxide in the air when dinosaurs were walked the Earth. Air bubbles trapped in amber suggest that the atmosphere may have consisted of as much as thirty-five percent oxygen in the Cretaceous Period. Today it is only twenty-one percent.
Giant dinosaurs living today may suffer from altitude sickness due to the lower oxygen levels.
It is unlikely that dinosaurs would survive today unless they could be kept in heavily controlled environments that closely duplicate their living conditions millions of years ago. This would be difficult because the atmosphere alone was so very different. There is no guarantee that they could digest modern plants, and food for them would be scarce.