Dinosaurs what do they look like

In those movies, all the dinosaurs are huge and all the iconic ones, they all kind of lived at the same time. But, both of those assumptions it turns out, are wrong.

Nic: The body size of an organism will dictate how it interacts with the world around it, its metabolism and so we can use body size to explore the evolution of dinosaurs. Dan: He told me that traditional understandings about the size of dinosaurs, as these large, cold-blooded reptiles goes back to the 19th century. And it kind of has to do with human nature in a way. Nic: The first discoveries of dinosaurs were very much focused on the sensational.

Dan: The technique researchers used in the 19th century to estimate the size of these dinosaurs was pretty rudimentary. Nic: So traditionally the first methods for estimating size in dinosaurs focused on reconstructing the animal in some sort of live, I guess, a sculpture effectively.

Dan: One famous 19th palaeontologist — and I should note controversial eugenicist — named Henry Fairfield Osborn was a really big proponent of this method.

Together, they would make a little model of, say, a Brontosaurus , and then use that to estimate weight and volume. Nic: And once you have that reconstruction, you dunk it in water, find out how much volume is displaced and that gives you the volume of a model. You scale that up to the size of the dinosaur and, voila, you have the volume of that dinosaur.

And once you have the volume, you multiply it by some assumption for body density and you have a body mass. And actually I find that some of these original estimates were not so far off.

Dan: This reconstruction technique has evolved quite a bit since then. Now, palaentologists use digital models rather than creating sculptures but the principle is kind of the same. But in the last years, a second approach has also been developed.

This one estimates dinosaur size and weight by measuring their limbs. Nic: It really just comes down to measuring bones and then testing to see how well they predict body mass in living things. And then making an argument about whether or not you think dinosaurs would have followed those same patterns.

So in the mid- 80s, there was a paper written by Anderson, Dale Russell , and they were the first ones to propose looking at living mammals, a relationship between the circumference of the humerus and the femur.

Dan: This approach was at first criticised. This was because the sample of living animals that they used to build the formula was originally pretty small. Nic: So the work that I did, going back now to early s was to try to test that. And so I compiled a giant dataset of living animals and each one of those skeletons was associated with a body mass.

Dan: Nic built a huge database of a tonne of different animals. It included rhinos, giraffes, elephants, turtles — even an orangutan. He then calculated the ratio between the humerus, an arm bone, and the femur, a leg bone, for each of these different animals to see if it could be used to predict mass. Nic: And I found that they were remarkably consistent.

And I guess our assumption is that somewhere along the spectrum of living animals, dinosaurs are likely to fall within that. Dan: Nic recently published a paper comparing these two methods: reconstruction and the limb measurement method.

Read more: How do you weigh a dinosaur? There are two ways, and it turns out they're both right. Most mass estimates of the two approaches converge on very similar results. Dan: The research that palaeontologists like Maria and Nic are doing today is certainly helping us get a better image of the ancient world.

But a lot of their work also helps answer questions about deeper ecological processes. It was very explosive. Dan: This kind of quick change is called adaptive radiation. It can also teach us things about animals today — for example, how they might adapt to changes or shocks to the environment. Read more: Prehistoric pigments reveal how melanin has shaped bird and mammal evolution. But fundamentally, I still kinda wanna know what dinosaurs looked like.

Maria: Number one, we would be incorporating dinosaurs of many different sizes. We would be including birds, because we now know that birds are just a type of dinosaur. They simply are the only group of dinosaurs that survived the end-Cretaceous mass extinction. You know, we preserve dinosaur eggs now, we know that they took care of their young.

I think it would really help bring them to life, actually, and make them much more tangible. Not these weird unknown ferocious beasts but, actually in many ways, a lot more familiar to what we see today. Gemma: So this is what we think dinosaurs look like in , but I guess in a hundred years from now it could all be different again?

Dan: One of things that was really interesting to me that both Maria and Nic mentioned, was that a lot of this stuff really depends on finding more fossils. So hopefully they all have some good luck digging in the future. Gemma: For the last two years, Israel has been in the grip of a slow-moving political crisis. With multiple elections failing to produce a stable government, Israelis voted in their fourth election in two years on March Dan: This time, the election was dominated by two main issues — coronavirus, and the corruption trial of prime minister Benjamin Netanyanhu, which actually began a few days after the election.

Gemma: The result was once again deadlock with no obvious majority. Now Netanyahu has been invited by the Israeli president Reuven Rivlin to try and form a government by early May. What happens next will have wide-reaching implications for the Palestinians, and the wider Middle East. And my main areas of interest in research really lie in foreign policy analysis and the foreign policy of Middle Eastern States. And are we any nearer to having a new government?

Read more: Stark choice for Israel as voters head to polls for fourth time in two years. Amnon: So this is the fourth election in two years in Israel, which really reflects a very profound, political crisis that has engulfed the country. In this fourth election in two years, we have effectively reached another political impasse. Prime Minister Benjamin Netanyahu has been leading what is defined in Israel as the centre-right group of political parties.

But together those parties have only reached 59 seats, which in the Israeli Knesset, the Israeli parliament, does not amount to the 61 majority, that is necessary out of seats. The opposing side, a group primarily of centre-left parties with some parties from the right who refuse to sit with Mr Netanyahu have not been able either to amass the necessary majority to create a coalition of 61 or more members of Knesset.

So where we are at now is that Mr Netanyahu, the prime minister, received the mandate from the president — the first go, if you like, to form a coalition government. He will have the opportunity to try and do that and somehow cross the line of 61 members of Knesset or members of parliament. And initially he has 28 days to do that. In Jurassic Park , the Brachiosaurus is the first dinosaur seen after everyone arrives on the island, memorably rearing up to get at some particularly delicious leafage.

But that behavior is now considered unlikely. Although this dinosaur certainly could have reared up , for example during mating, this was probably a rare and short-lived event. The Spinosaurus was discovered only a few years after the Tyrannosaurus , but it never attracted fans in quite the same way.

The fossils were destroyed in World War II during an Allied bombing raid on Munich, and the dinosaur became largely forgotten. Many fans cried foul, and the size of the Spinosaurus was indeed a mistake … in reality, it was much bigger. It would have been up to three times heavier and 20 feet longer; a creature on the higher end of that range would have been bigger than even Jurassic World 's invented I.

But could Spinosaurus have taken on a T. Almost certainly not. While physically bigger and armed with a bigger jaw, it was much less powerful, as most paleontologists now believe Spinosaurus used its long jaws for fishing.

It actually lived mostly in the water. It's an ingenious idea, but one that remains deeply within the realms of science fiction , at least for now. So, given that we're unlikely to see dinosaurs roaming our zoos and safari parks anytime soon, how do scientists determine how these amazing animals fed, ran, bred and died?

Palaeontologists - the scientists that study extinct life - have a surprising array of tools for examining the fossilised remains of animals and plants to determine how they might have appeared and behaved when alive. Nest containing eggs, probably those of the theropod Citipati , found in the Gobi Desert, Mongolia.

These dinosaur eggs are around 80 to 85 million years old. Scientists can learn about a dinosaur's egg-laying and parenting strategy from the number of eggs and the way they are arranged.

Dinosaur footprints reveal the size of the animal and how it walked: on two legs or four. The stride length can also be used to calculate how fast the dinosaur was moving. These tracks in Dorset, UK, were made by an Iguanodon -like animal. Fossilised poo, called a coprolite, sometimes contains evidence of an animal's past meal.

These droppings found in India are believed to have been left by a dinosaur around 70 million years ago. The dark bits are pieces of plant, so the dinosaur was probably a herbivore.

In the case of dinosaurs we have their skeletons, but we also have other evidence that can give insight into their daily lives, including preserved gut contents, eggs, nests, footprints, skin impressions and even dinosaur poo. Comparisons with living animals are also key. Detailed examination of skeletons provides information on the shapes of the bones and how they fit together.

Palaeontologists sometimes find the fossilised remains of a dinosaur preserved in the position it died, as with this Coelophysis fossil skeleton. They can see what bones were next to each other and how the joints worked. Using this information they can reconstruct the dinosaur and how it moved. Reconstructed Triceratops skeleton found in the USA.

If an excavation reveals dinosaur fossil bones that aren't arranged as they were when the animal was alive, palaeontologists use knowledge of anatomy and comparisons with other animals to piece together the skeleton. If we can identify similar features in living animals, whose biology we can study in real time, we can infer similar functions for those same features in extinct animals.

Rough patches and flanges on bone can be used to reconstruct the positions of muscles, cartilage and ligaments. Scientists can deduce a dinosaur's diet from the shape of its teeth. Analysis under a microscope may reveal wear marks that give further clues to what the dinosaur ate and how. The interlocking teeth in this Edmontosaurus jaw formed a grinding surface for eating tough vegetation.

This type of work has been carried out since dinosaurs were first discovered in the early eighteenth century, and continues to provide new results today. However, this classical approach has been expanded thanks to an array of modern technologies, pioneered in fields from medicine to engineering, which are now being applied to fossils on an almost routine basis.

Perhaps the most significant advance has been the application of computed tomographic CT scanning. This technique uses rotating X-rays to build up a 3D model of both the internal and external anatomy of an object. It has diverse uses, ranging from diagnosing illness to checking car or airplane parts for flaws before they leave the factory floor. CT scanning can be used to peer inside dinosaur bones and reveal features of the skeleton that were previously difficult to access, including the shape of the brain and the presence of air-filled sacs that ran through many dinosaur bones.

Museum dinosaur researchers used a CT scan of a Stegosaurus skull to produce a 3D digital model. They used biomechanical tests on the model to show how Stegosaurus chewed and found that it had a particularly powerful bite for a herbivore.