What would have happened if dinosaurs had not disappeared?

It is common knowledge that with the help of “if” we remake the world. But what would the world look like if we took a moment to imagine that dinosaurs hadn’t gone extinct? Would things be different? Have we seen intelligent dinosaurs emerge? And, above all, would a person impose himself as he does today? There are so many questions that will never be answered, but which, thanks to our current knowledge of evolution and evolutionary processes, we can have fun with using plausible scenarios.

Dinosaurs: 170 million years of world domination

Let’s first rethink the scientific context. Dinosaurs represent treasuretreasure quadrupedal vertebrates (having two pairs of limbs) of the sauropsid class, which today includes reptiles and birds. Appearing about 240 million years ago, at the beginning of the Triassic, dinosaurs reigned supreme on the planet. EarthEarth to end Cretaceous periodCretaceous period, 66 million years ago. During these approximately 170 million years (for comparison, humans have existed for only 3 million years), they managed to experiment with all sorts of sizes, body shapesbody shapes, means of protection and transportation. Present throughout the globe, from one pole to the other, in all types of environments, both on land and in seas and in melodiesmelodiesDinosaurs have left their mark on Earth’s history far more than any other group of animals.

The length of their reign is proof of their enormous ability to adapt. Because over 170 million years, dinosaurs had to deal with many changes: the evolution of continental surfaces from movementmovement tectonics, extreme variations climateclimate, sea level fluctuations, volcanic crises… Despite these ever-changing environmental constraints, dinosaur diversity has only increased over time. Thus, two main lineages gradually emerged: the avian lineage, characterized by small dinosaurs. theropodstheropodsand the non-avian lineage, which, in particular, gave rise to numerous varietyvariety giant dinosaurs.

Until the end of the Cretaceous period, dinosaurs occupied all ecological niches. They really are everywhere. Until this catastrophe that will end their reign. 66 million years ago there was a fall asteroidasteroid will hasten the end of their reign. The environmental disaster caused by this impact combines with conditions already worsened by the massive eruption of the Deccan Traps. This is too much even for these champions of adaptation. This is extinction, fast and brutal.

Dinosaurs are still among us… and there are many of them!

If we often characterize chalkPaleogenePaleogene extinction of dinosaurs, but it should be clarified that this does not apply mass extinctionmass extinction What non-avian dinosaursnon-avian dinosaurs. Many small avian species survived… and thrived! Because yes, dinosaurs are still among us. They even suppress us mammalsmammals, by number of species. These are birds. From point of view phylogeneticphylogeneticBirds are indeed theropod dinosaurs of avian origin.

Thus, dinosaurs did not disappear completely. And this is the first element of the story in the context of our original question: what would the world look like if dinosaurs had not disappeared?

A dominance that would surely last for a long time.

So let’s assume that the asteroid didn’t hit Earth 66 million years ago and that the eruptions Deccan TrapsDeccan traps were less severe than they were. Given the history of dinosaurs, it is already very likely that they continued to dominate the world until today, adapting as they evolved. And obviously the most adaptable form is birds. Therefore it is possible, as Eric Buffeteau and Guillaume Lecointre described it in the show. Scientific method on French culturethat avian dinosaurs saw their diversification increase, perhaps to the detriment of sauropodssauropods giants.

So the world might eventually have been dominated by birds with an even greater variety of shapes and sizes than we know today, as well as small, fast theropods such as raptors. But could these animals have evolved into intelligent forms that allowed them to develop technology?

Is cognitive evolution possible in dinosaurs?

Dale Russell paleontologistpaleontologist, imagined how dinosaurs could have evolved into an intelligent form capable of producing tools. This is a “dinosauroid”. Form humanoidhumanoid bipedal with big brainbrain and opposable thumbs. Was such an evolution possible? Hard to tell. Some scientists, at least, don’t believe it. Such is the case with Nicholas Longrich, who published an article in Talk.

L’evolution of speciesevolution of species is actually limited by certain anatomical and metabolic features that will determine the direction of evolution, while leaving room for some maneuver. During their 170 million-year reign, dinosaurs, unlike mammals, did not appear to experience favorable brain development. Throughout their reign, dinosaurs did exhibit relatively low cervical mass compared to body mass. Mammals, for their part, quickly acquire large brains relative to their size. Does this mean that dinosaurs were doomed to never develop cognitively? Impossible to know. We note that some modern birds do have brains quite large for their size, and behavior that can be called intelligent, similar to crows.

What if birds were actually, like today, an advanced and intelligent form of dinosaurs? After all, their cognitive evolution would be slower than ours, but there’s nothing to say that they won’t catch up in a few million years…

Besides, if extinction didn’t happen, what about humans?

Could mammals replace dinosaurs?

We must not forget that mammals did not appear after dinosaurs. They were there long before them too. During the Triassic, anatomical diversity was even enormous among small mammals, which were present in all habitats. Therefore, they developed completely in parallel with dinosaurs, for whom they were not only prey. Some fossilsfossils show that some large mammals may once have been predators of dinosaurs.

However, in the long term the results are clear. In 170 million years, mammals failed to overthrow the dinosaurs, and it is unlikely that they would have succeeded in displacing them if the extinction had not occurred. Perhaps they would have evolved along with them, but the massive occupation of ecological niches by dinosaurs would not have left much room for the development of mammals. In fact, it is likely that intelligent human beings never came into being.

Evolution is truly a matter of environmental constraints and conditions (wild naturewild nature, flora, geography, climate), but also luck, chance and opportunity. This is how the human line arose and developed from primatesprimates, on the African continent and only in this region of the world, because conditions there were favorable and developing opportunities presented themselves at the right time. But nothing was written in advance. While it is certain that the extinction of the dinosaurs contributed to the dominance of mammals, it is not clear that it was the certainty of the emergence of a species, ours, endowed with a strong intelligenceintelligence.