Are you a curious person? Do you love science and like to get answers?
Then you are like us! Welcome toMesozoBlog.
In this article you will find out:
- What's the difference between sharks and dinosaurs.
- How old are sharks as a species
- How old are dinosaurs
- How did sharks survive the mass extinction
Before going into details you may be waiting for an answer, have sharks been on earth longer than dinosaurs?
Yes, sharks are older than dinosaurs. The oldest species of sharks appeared on earth about 420 million years ago. Dinosaurs on the other hand appeared about 240 million years ago. So we can say without any doubt that sharks are older than dinosaurs.
We will now go into more detail. You'll know everything there is to know on the subject.
Let’s find out it together.
First Of All: Are Sharks Dinosaurs?
Before we begin, it seems important for us to go back to the basics. In order to have a better global understanding of the subject.To answer clearly and precisely, no, sharks are not dinosaurs, although they are prehistoric animals.
Now let's get to the heart of the matter.
1) What is a dinosaur
This may sound like a silly question, after all, we all know what a dinosaur is. We've all heard of them before. But from a scientific and biological point of view... What really is a dinosaur?
Dinosaurs are a very diverse group of prehistoric animals and now extinct, long considered reptiles, modern research is now less categorical. They are oviparous archosaurs, just like modern birds or crocodiles.
They were mainly land-living animals, although there were a few exceptions, such as the Spinosaurus, which was both terrestrial and marine according to the latest discoveries.
2) What is a shark
This too may seem a bit silly as we all know what a shark is. But let's go back to scientific explanations and categorizations.
Sharks are also a very diverse group of marine animals belonging to the chondrichthyes family or more commonly known as cartilaginous fishes.
Like dinosaurs, sharks are a group of prehistoric animals. Today there are more than 400 species of sharks divided into more than 30 families.
3) Are sharks considered dinosaurs
Although dinosaurs and sharks are both prehistoric animals they are actually very different, as seen previously sharks are fish and therefore they are not dinosaurs. They actually have very little in common.
Just like sharks, carnivorous dinosaurs could have multiple rows of teeth, the teeth being replaced automatically as you go along to limit wear and tear and continue to kill your prey.
It's one of the only things the two species have in common.
A common mistake is to consider that all prehistoric animals and especially predators are dinosaurs. Thus the giant prehistoric Megalodon shark is often confused with a marine dinosaur.
In reality, this is not the case.
And no matter how big it was, it was a fish, a big and very dangerous prehistoric fish, but still a fish.
4) Are sharks related to dinosaurs
As explained earlier, modern sharks are the descendants of prehistoric sharks that lived and swam alongside and at the same time as dinosaurs. But they are not directly related. They're not even close. If we go back much further, we might indeed find an ancestor common to both species, but we would have to go back hundreds of millions of years, and at that point, all species will find their distant cousins.
So no, actually on a scientific point of view it’s even pretty incorrect to say that sharks are related to dinosaurs.
Sharks and Dinosaurs: How Old Are They?
Now that we understand who the dinosaurs were and who the sharks were, and that we understand the differences between them, we can take a closer look at their stories and origins.
And the least we can say is that both are really very very old, with a victory on the sharks' side.
1) The appearance of sharks
According to current knowledge, the first sharks appeared around 440 million years ago. In Devonian times. It is relatively difficult and rare to find shark fossils, mainly because of their fish nature and their cartilaginous skeletons that are not very resistant to time. Fortunately, they had many teeth, and it is often thanks to them that they can be identified.
Sharks were not always super predators and many specimens found show us that they were even more prey, at a time when the oceans were much more dangerous places than they are now.
Modern sharks are the last evolutionary development to date and are thought to have appeared about 100 million years ago.
2) The appearance of dinosaurs
250 million years ago a cataclysm whose nature is still subject to debate wiped out nearly 90% of living species. Ending the Permian era of the Paleozoic period and starting the Triassic era of the Mesozoic period.
And so began the age of the dinosaurs. The oldest dinosaur fossils found to date are carnivore fossils dating back to the middle Triassic period, about 230 million years ago.
Dinosaurs are believed to be descended from archosaurs, a group of animals that also gave birth to crocodiles.
Dinosaurs ruled the planet for nearly 160 million years. Before suffering a more tragic fate, which we'll discuss in the next chapter.
Did Sharks Survive Dinosaur Extinction?
After all, we've just discussed, it may seem strange to think that sharks have traveled hundreds of millions of years like this while other species appeared and then became extinct.
Indeed, not only did sharks survive the mass extinction that killed the dinosaurs, but they also survived the previous mass extinctions on the planet. You could say they're tough guys, or they're very lucky.
1) What is the dinosaur extinction
But before explaining how they did it, let's recall a little bit, what exactly was the dinosaur extinction.
The dinosaur extinction is a mass extinction that affected planet earth and marked the end of the Cretaceous and Mesozoic eras.
Its exact course is subject to debate in the scientific community. But it is in fact probably a succession of cataclysms which, because of its violence and duration, would have made living conditions on earth incompatible with animal or plant life and would have led to the disappearance of most living species.
The dinosaurs as well as most of the living species on the planet have thus disappeared and this is how the era of the dinosaurs came to an end and gave way to the era of the mammals.
2) How did sharks survive it
One question we can legitimately ask is, how did the sharks survive this? Not only the dinosaur extinction but also the previous mass extinctions, how is it possible to survive in a world undergoing cataclysmic change.
Sharks have very strong and unusual resistance.
We could summarize it this way. Although in reality many species of sharks did not resist mass extinctions and disappeared along with many other animals. But the order of sharks has always resisted and always survived.
For a long time, scientists have been trying to discover the secret of sharks, or how they have been able to survive for so long. One of the theories lies in the sharks' diet, the shark is a glutton, it bites everything it finds. As soon as the food runs out, the shark swallows whatever it finds. Some sharks may even become vegetarian and eat seaweed from the seafloor.
This plus the fact that sharks tend to adapt to different climates in a frighteningly efficient way may explain how the shark has managed to survive through the ages while other species were slowly disappearing.
Here we are, it's over, you are now aware of the age of sharks, what they have in common with dinosaurs, and their history through the eras.