Dinosaurs Are Not Extinct: An Interview with Paleontologist Jean-Sébastien Steyer

Jurassic World returns to our screens on July 2, 2025, but to wait while waiting for the return of dinosaurs and the star franchise which had its debut with Jurassic Park In 1993, why not immerse yourself in a little reading with the last work co-written by the paleontologist Jean-Sébastien Steyer “Jurassic Park and the sciences” available since October 30, 2024.

© Belin Publisher / Jean-Sébastien Steyer

Besides, we were able to exchange a little, by email, with the author who answered a few questions that almost everyone is asking about dinosaurs.

Science & Life – Let's start with a classic. Is the vision of Tyrannosaurus Rex really based on movement?

Jean-Sébastien Steyer : Yes, the vision of T. Rex is partly based on movement: its orbits are located on the face and in the same plane; This makes it possible to understand not only the relief but also the distance from the prey and the slightest movement. However, according to the reconstructions of the endocranial structures of the T. Rex, it also used hearing and smell to hunt.

S&V – The era of giants (air, land, sailors) is no longer, how can we explain it?

JS.S : The “era of giants” is a false term because 80 % of dinosaurs did not exceed two meters high. We talk a lot about the biggest, Diplodocus And others, but it is especially for media reasons. However, some species were really very large. We observe that the more a population is doing well, that is to say the more food, space, and few predators, the more its individuals increase in size.

S&V – How are dinosaurs named?

JS.S : To name a dinosaur or any other fossil species, we must follow the international zoological nomenclature code. It is a bit like the road code of the paleontologist: we can attribute to the dinosaur the name of his place of discovery, the name of the person who discovered it, a name derived from one of his anatomical characteristics, etc. The important thing is to be sure that it is indeed a new species!

S&V – In Jurassic Park and later in Jurassic World, we resuscitate the dinosaurs. Is it possible and is it really a good idea?

JS.S : No, it is not possible to resuscitate a dinosaur living from fossil fragmentary DNA. But we can comfort ourselves because birds are classified in dinosaurs in terms of phylogeny (study of kinship relationships). We can say that the dinosaurs have not all disappeared: some today have feathers!

S&V – This is reminiscent of the Colossal BioSciences project which wishes to bring back the woolly mammoth, the tiger of Tasmania or the dodo. What do you think?

JS.S : These species are much more recent than dinosaurs. Today we have very well preserved fabrics (skin, flesh) with DNA inside. If we find still viable cells, it might be possible to clone them. But for what to do? For what purpose? These species lived in a very different time and under different climates. They would not be adapted today and would die quickly.

S&V-Jurassic Park, did he not hurt your job? In particular with regard to the appearance of dinosaurs and sounds they could have emitted.

JS.S : Not because, in addition to certain reconstructions a little too “poetic” in fact, the saga shows on the contrary the dangers of private funding in public research. Indeed, the history paleontologist, Alan Grant, is bought by the billionaire John Hammond. He is no longer independent and his research is then oriented towards those of the park …

S&V – If these animals were brought back to life, would they not have difficulty adapting to the living conditions that we know today as well as an environment which in no way resembles that which Did they know?

JS.S : Yes. They would no longer be adapted to our contemporary environments which are today unfortunately very impacted by humans. There are still many virgin areas on our planet. The dinosaurs would therefore lack space and return to competition with other current species, including mammals, including humans.

S&V – Conversely, if we, humans, were transported in the past, would we have adaptation difficulties?

JS.S : Without technology, we would be completely helpless! Only a few survivalists or scientists in the field, who have a little habit of extreme environments or conditions, perhaps would come out … frankly, in front of spinosaurs, T. rex or mosasaurs in the seas , we would not make the weight!

S&V – In the first opus of Jurassic Park, Alan Grant declares “man and dinosaur, two species separated by more than 66 million years, have just been found. How can we have the slightest idea of ​​this that it would give “. And if hypothetically, this meeting could take place, what reports would they have?

JS.S : It would go wrong for dinosaurs alas, because humans are also a wolf for other species: hunting, destruction of natural habitats, pollution, overconsumption, … it is not for nothing that, in the saga, Dinosaurs become either fair monsters or war beasts.

S&V – In 1993, Jurassic Park evokes female animals that reproduce, can we then speak of parthenogenesis in dinosaurs?

JS.S : We do not know if it really took place in certain species of dinosaurs. We know that certain lizard species are reproduced by Parthenogenesis. But from there to imagine all the dinosaurs capable of reproducing in this way … We are well in science fiction!

S&V – What would a French Jurassic Park give?

JS.S : France is very rich in dinosaurs, the big forgotten in the collective imagination, for the benefit of American and Hollywood species. The “French” jurassic park would host the big Ampelosaurusthe fast VariraptorTHE RhabdodonTHE PlatéosaurusTHE Struthiosaurus battleship and many other species.

S&V – The first opus of Jurassic World posed, with Indominus Rex, the question of a possibility of hybrid dinosaur. Is it possible, as is the case in nature today, that a hybridization between two species of dinosaurs took place?

JS.S : Yes but not as much asIndomimus Or Indoraptor Who are pure chimeras because these genres were built, in the saga, from DNA of very distant species, like the cuttlefish! It is not viable. Hybridization is in reality possible, in fairly close species, but it remains quite rare in a natural environment.

S&V – The Disney Dinosaur film evokes cohabitation between dinosaurs and primates. If we know that small mammals have lived alongside terrible lizards, were they able to share the land with the greatest animals that the planet worn?

JS.S : The first primates correspond to fossils aged approximately 55 million years. They therefore appear 11 million years after non-Avian dinosaurs, birds aside.

S&V – Will we have one day discovered all the dinosaurs?

JS.S : No ! Thanks to the erosion which brings to light more and more rocks of the mesozoic era (the period of dinosaurs) on the surface, we, paleontologists we discover more and more dinosaurs. And this, throughout the globe, understood in Antarctica. So there are still thousands of species of dinosaurs to discover!

Only a few months to wait before finding the terrible lizards on the big screen. And besides that is good, the trailer of Jurassic World Rebirth just went out:

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