Dinosaur Week

Dinosaur Week

Period: 22-28 February 2021

This week we are going to find out all about Dinosaurs!

We will learn lots of interesting facts about Dinosaurs, including where they lived, what they ate and how big they were.

Sections


Activities

What are Dinosaurs?

There have been many different animals that lived in the place we now call home. Some prehistoric animals are closely related to the animals that live today, some not so much. One group of reptiles we like to talk about are the dinosaurs!

Some prehistoric animals get called dinosaurs but aren’t really dinosaurs at all! For example, pterosaurs are flying reptiles but do not belong to the Dinosaur classification. Same with the plesiosaur – it’s actually a marine reptile, not a dinosaur!

So When Is A Dinosaur A Dinosaur?

Animals have to meet specific requirements to be called a dinosaur:

  • Lived on land (not water, except some modern birds)
  • Laid eggs
  • Had legs perpendicular to their body (not just sticking out the sides)
  • Had two holes behind their eye sockets for strong jaw muscles to open wide and clamp down hard

They also lived specifically in the Mesozoic Era, which can be broken up into the Triassic, Jurassic, and Cretaceous Periods.

How do we know so much about dinosaurs? Fossils!

Fossils

Fossils are the hardened remains of plants, animals, or other life that can be found in the ground. Fossils are formed when something dies and is covered in layers of mud and other compounds.

Over millions of years, water seeps into the animal's hard parts (like bones) and leaves behind minerals.

Those minerals replace the bone over time and create a rock in the shape of the animal that was once there! You can also find impressions which are things like footprints, leaf prints, or patterns from the skin, fins, or feathers left in the mud or rock. On the Isle of Skye, you can actually follow a trail of dinosaur footprints fossilised in the mud on the beach!

Watch this video from the Natural History Museum to learn more about how fossils are made.

How Fossils Are Made (Natural History Museum)

Fossils can help tell us a lot about how animals lived and what the environment was like at that time. For example, if they had sharp, cone-like teeth, they were carnivores; if they had flat, bumpy teeth, they were herbivores.

It’s important to know, though, that most living things did not become fossils, so while they are really good at telling us some things, we will never get a complete picture of what life was like just from fossils. That’s when we need to rely on things like geology (what the rocks and rock formations can tell us) and climatology (how the weather and climate develop).

Did You Know? Until last year, the only dinosaur bones found in Scotland had been found on the Isle of Skye? A palaeontologist from National Museums Scotland discovered a stegosaurus fossil on the island of Eigg, which means there were dinosaurs there during the Middle Jurassic Period – a period not many scientists know too much about!

Now try some of our activities, and send your photographs to us of how you get on.

Don't forget to send us your photographs and enter our competitions to win some prizes.

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Free eBook About Dinosaurs (PDF)
Free eBook About Dinosaurs (PDF) from Free Kids Books
Dinosaurs At Natural History Museum
Dinosaurs (Natural History Museum)
Make A Model Dinosaur Activity
Dinosaur Game (BrainPOP)
Dinosaur Songs: T-Rex, Velociraptor & More (StoryBots)
Eigg Beach Runner Stumbles On Dinosaur Bone (BBC News)
Eigg Beach Runner Stumbles On Dinosaur Bone (BBC News)

When and Where did Dinosaurs Live?

So we know that dinosaurs lived in the Mesozoic Era, but how long ago was that exactly?

This web site gives you a look at just how far back that was hereistoday.com

When you get to the current aeon, you will notice three eras: Paleozoic, Mesozoic, and Cenozoic. Dinosaurs existed only in the Mesozoic era, we are at the very end of the Cenozoic period.

Have a go at the Geologic Time Scale Activity (PDF) to get a better understanding of just how long ago the dinosaurs lived!

Ok, so dinosaurs lived a really long time ago, but WHERE did they live? Well, to answer that, we need to talk about something called plate tectonics (remember that we learnt about back in Planet Earth week). The centre of the Earth is mostly molten, liquid rocks that the crust floats on. The crust is the land we walk on, the bottom of the oceans, and goes down anywhere from 5-70 km (depending on where you are on Earth). The crust isn’t just one solid plate, though. It’s made of lots of separate plates that are constantly moving – which is why we get earthquakes and some volcanoes. This means that millions of years ago, Earth looked A LOT different than it does now.

At the beginning of the Triassic Period – the beginning of the Mesozoic era – all of the landmasses were connected in a supercontinent called Pangaea. This means that there were dinosaurs all over what we now call the seven continents. It was very dry in the centre of the continent with monsoon-like weather around the coastlines during this time. There were also no ice caps at this point.

At the beginning of the Jurassic Period, Pangaea was split into two continents called Gondwana and Laurasia. These continents also began to split by the mid-Jurassic into many of the continents we recognize today. In between these continents, the seas began to flood in, creating a more humid, subtropical climate. This time is known as the Golden Age of Dinosaurs – a time when dinosaur species began to diversify, or change a lot, because they were separated by the oceans.

Read more about a theory that dinosaur farts may have led to climate change at www.smithsonianmag.com.

Finally, in the Cretaceous Period, the continents drifted still further, closer to what we now recognize today. The sea level changed a lot during this time, with temperatures spiking in the middle of the period and then falling towards the end. During this time, different kinds of dinosaurs became common in specific locations – giant sauropods in the south, and at the end of the period, T-Rexes and other giant meat eaters dominated in the north. There were also various mammals, reptiles, birds, and fish which can be compared to modern day descendants. The Cretaceous Period, unfortunately, was the last time the dinosaurs would rule the Earth, though. On Friday, we will talk about some of the ways scientists think dinosaurs went extinct at the end of the Cretaceous Period.

What If Earth's Age Was Just 1 Day
Geologic Time Scale Activity (PDF)
List of Tectonic Plates
List of Tectonic Plates (Larger Image)
Jurassic Period Scotland (Scottish Geology)
A map of what landforms may have looked like in Scotland in the Jurassic Period (this does not reflect its actual location, just what the land may have looked like). (Scottish Geology)
QR Code for Plate Tectonics Video
If you’re curious about how the continents are moving, scan this QR code to watch a really cool video explaining plate tectonics.

What Did Dinosaurs Eat and How Big Were They?

Dinosaurs ate lots of different things, and it changed depending on where they lived and how big they were.

Enormous sauropods like Brachiosaurus, Dreadnoughtus, and Titanosaur, were herbivores, that is, they ate plants. Because they were so big, they had to eat thousands of kilograms worth of food every day! There is a bit of a debate, though, about how they were able to digest their food. Most did not have the teeth to chew, only to pull leaves from branches. Some scientists believe they will have swallowed rocks like some birds do to grind up their food in their stomachs; whereas, other scientists believe they may have had lots of microbes in their bellies to digest their food for them. Recently, research suggests that they did not have stones in their stomachs, but that they held on to their food for very long periods to digest it.

Ornithischians like triceratops, ankylosaurs, and hadrosaurs are also well-known to have been herbivores, but they were much smaller than the sauropods, meaning they ate plant material closer to the ground. These dinosaurs had an extra bony tip on their lower jaw, and many rows of teeth in their jaws, as well as powerful cheek teeth for grinding their food.

Perhaps the most interesting is that theropods, those we typically think of as being predatory carnivores, weren’t all exclusively carnivorous! Some of these dinosaurs ate plants as well, making them omnivores! At least 44 species of theropods (specifically coelurasaurs) did eat plants! Of course, tyrannosaurs and raptors were among the strict carnivore groups, but this means that dinosaurs who only ate meat were the odd ones out!

So how big were these animals? In modern times, the largest animal on Earth is the Antarctic Blue Whale. It can reach 30 m in length (approximately 3 buses end to end) and weighs up to 400,000 pounds (33 elephants!).

The largest sauropod we know of was the Argentinosaurus. Scientists estimate this dinosaur to have been somewhere between 37 and 40 m long and would have weighed around 90-100 metric tonnes (about 18 elephants). Not only would it have been 1/3 longer than the Blue Whale, but it would have been about 21-24 m tall – as tall as a 6-story building. Most sauropods were about 15-20 m in length.

Ornithisician dinosaurs vary quite a lot in size – some being as small as a dog, and others growing to 15 m in length! Most seemed to fall in the range of 2-8 m, however.

Theropods, however, varied the most in size. The smallest theropods were only about 34 cm in length (almost as long as a laptop), and the largest – Spinosaurus aegyptiacus – was around 15 m in length. Until recently, the T-Rex was believed to be the largest theropod at around 12-13 m long.

Try out the activity below to compare some of these dinosaurs' sizes to things in your home!

Dinosaur Footprints Activity Sheet (PDF) (The Geological Society)
How do we know what dinosaurs and other extinct animals ate?
Argentinosaurus Eating (BBC’s Planet Dinosaurs)

What Happened To The Dinosaurs?

Dinosaurs lived on Earth for 180 million years – that’s a really long time! Modern humans have only been around for 200,000 years, that’s 1/900 as long as dinosaurs were around! If we try to visualise that, the UK is a little more than 900 km long. The existence of dinosaurs would take up the whole length of the UK, and modern humans would only take up 1 km – that’s a little less than half of the Tay Road Bridge!

We know that dinosaurs went extinct – or died out – at the end of the Cretaceous Period rather abruptly. So how did these gigantic animals suddenly disappear?

Scientists are still trying to work that one out. There are lots of theories that might point to why the dinosaurs went extinct during this time. One well-known theory is that an asteroid or comet hit the Earth in what is today the Yucatán Peninsula off the coast of Mexico. The meteor is believed to have been about 10 and 15 km wide. When it hit the Earth, the asteroid itself vaporised, but it sent tidal waves and a shockwave and heatwave out. It threw up so much soot and debris that it reduced the amount of sunlight that could reach plants. The area right around the impact was completely destroyed. Because plant life began to die, herbivores did not have enough food, which meant eventually, carnivores would have less food as well. These very large animals could not find the food they need to sustain their body masses, and so they would have died as well. About 75% of the animals on Earth would have died after this event.

However, the asteroid wasn’t the only baddie here. During the Cretaceous Period, there was a lot of fluctuation in sea levels and climate change. The Earth was undergoing another climate change when all of this happened. Because the continents were splitting, there was a lot of volcanic activity going on, which also increased the temperature, and made it harder for life to exist in certain areas.

After the asteroid impact, flowering plants dominated the Earth, and large animals over 25 kg died out. The only dinosaurs that survived were birds. If you’ve ever eaten chicken nuggets… you’ve eaten dinosaur nuggets! Small mammals, birds, and other animals survived and life similar to today began to flourish.

How Dinosaurs Transitioned into Birds

So, what would have happened if the asteroid had not hit or had hit somewhere else? We’ll probably never know, but the world today would definitely have looked a little different!

Activity Check out the Dinosaur Next Door activity to reimagine a world with dinosaurs!

Dragons, Gryffins, and Other Monsters

Palaeontology is the study of the history of life. In ancient times, people found fossils of these long-dead organisms, but did not know what they were. Many of these fossils became the basis of many of the myths we have heard of today – like dragons and cyclopes.

In Asia, myths about mythical birds, gods, heroes, and animals have existed even today. In Mongolia, theropod tracks discovered in the 1950s were believed by local farmers to be a god-like bird that wished well for humans. Hadrosaur footprints had also been mistaken as ancient etchings in stone by divine beings. A fossilised stegosaurus was discovered in the 4th century BCE in present-day Sichuan Province, and it was understandably mislabeled a dinosaur because of its long neck and bony spikes for protection.

Where did dinosaurs come from? (Natural History Museum)

In Ancient Greece and Rome, many monsters and giants told in myths can be traced to fossils found in the area. For example, the Cyclopes in Homer’s epic tale The Odyssey may have come from fossilised skulls of dwarf elephants who had died out thousands of years before the Greek civilisation formed. The centre of the skull had a large hole for the elephant’s trunk, but without anything to tell them otherwise, it looked a lot like an eye socket! Griffins were also a mythological creature that the Ancient Greeks traced to nomads (people who wandered rather than staying in one place) from modern-day Ukraine. It was thought these monsters had the body of a lion and the head, talons, and wings of an eagle. Today, it is believed that this was the fossilised skeleton of a Protoceratops. Sea monsters, dragons, and giants can all be traced from the Greeks to various fossils of extinct animals – dinosaur or otherwise.

Even Native American legends are filled with beasts that, today, we can trace back to prehistoric animals. Mammoths, dinosaurs, pterosaurs, and marine creatures were portrayed as Monster Bears, Giant Lizards, Thunder Birds, and Water Monsters in several different oral histories from varying tribes.

Even since the creation of modern palaeontology, scientists have revised their ideas about dinosaurs. For example, many Victorian palaeontologists would take modern-day reptiles and blow them up to fit the size of the bones found. This led to many fossils being put together incorrectly – for example, displaying the Megalosaurus as a four-legged rather than a two-legged dinosaur. Today, we even know that many raptors were covered in feathers!

The great thing about science is we are always learning something new. We add to what we know and make the best theories to fit the evidence we find. Who knows, maybe you’ll make the next great dinosaur discovery!

Griffen is a legendary creature with the body, tail, and back legs of a lion; the head and wings of an eagle; and sometimes an eagle's talons as its front feet.
Dinosaur Park
Dinosaur Park - The world's first dinosaur park: what the Victorians got right and wrong

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