Tyrannosaurus rex


A skeleton of Tyrannosaurus rex.

A skeleton of Tyrannosaurus rex.

Its name means the “terrible lizard king” and everyone knows its sharp-toothed smile.The star of countless books and films; it could be no one else but Tyrannosaurus rex.

Discovery: the first T.rex fossil was first found in 1902.

Height: 5.6m

Length: 12m

Weight: 7000kg

Where it lived: Fossils of T.rex have been found in North America. There is a very closely related  species found in Mongolia in Asia called Tarbosaurus

When it lived: it lived 67-65 million years ago in the Late Cretaceous.

What it ate: T.rex ate meat. Palaeontologists have debated whether it was a scavenger or if it hunted its own food. Teeth marks are found in other dinosaurs which match a T.rex tooth. T.rex likely did both like many animals do today.

Weapon of choice: a massive head with rows of teeth up to 20cm long. Despite its reputation from Jurassic Park, T.rex had excellent vision. Standing still wouldn’t save you if it had you in its sights.

Weakness: Its two small arms with only two fingers. Their only use was scratching its belly after a big meal.


A Triceratops skeleton. (Wikimedia)

A Triceratops skeleton. (Wikimedia)

A big dinosaur with some massive horns, Triceratops is one of the best known dinosaurs. If it was alive today, its massive size and horns would scare away any predator but Triceratops lived alongside one of the biggest predators of all time, Tyrannosaurus. Fossils show that these animals fought many battles together.

Discovery: Triceratops was first found in 1888 and was named in 1889.

Height: 3m

Length: 9m

Weight: 5500kg

Where it lived: Triceratops fossils are found in North America, both U.S.A and Canada, and are found in the Hell Creek Formation and other formations in America.

When it lived: It lived at the end of the dinosaur period, 72-65 million years ago in the Late Cretaceous.

What it ate: Triceratops was a plant eater.

Weapon of choice: Its three big horns that could measure over a metre. They used them to fight other Triceratops and its predators.

They are very common fossils which makes many palaeontologists think that Triceratops travelled in herds.

Weakness: Triceratops was big but not big enough for hungry T.rex. (although T.rex would probably have avoided a fully-grown, healthy Triceratops)


The skull of Pachycephalosaurus.

The skull of Pachycephalosaurus.

Pachycephalosaurus means “thick headed lizard” and refers to their thick, dome shaped skull that could by 25cm thick, despite being a small(ish) dinosaur. It is a very rare dinosaur and is only known from one skull and a few pieces of its dome.

Discovery: Pachycephalosaurus was discovered in 1938

Height: The height is hard to work out without a whole skeleton but palaeontologists think it was around 2m tall (largest estimates are 4m).

Length: The estimate is about 4.5m long (upper estimates are 8m)

Weight:  Maybe around 430kg.

Where it lived: North America in modern day Monatana.

When it lived: It lived about 75-65 million years ago in the Late Cretaceous.

What it ate: Scientists aren’t sure. It had very small teeth so it was likely a plant eater but may have eaten insects as well.

Weapon of choice: Its thick skull. Some palaeontologists (but not all) think it used its thick skull to protect its brain as it rammed heads with other Pachycephalosaurus. That head could be dangerous against predators as well.

Weakness: Pachycephalosaurus was quite small for a dinosaur and its brain was even smaller. We can’t be sure if it was hunted by any predators but it’s likely that it was.


Artistic impression of Ankylosaurus. (LadyofHats, Wikimedia)

Artistic impression of Ankylosaurus. (LadyofHats, Wikimedia)

Ankylosaurus means “fused lizard” and it is called this because of its bulky body armour. It wasn’t the biggest dinosaur, but it didn’t need to be as its armour of bones and plates was all the portection it needed.

Discovery: Ankylosaurus was first named in 1908

Height: 2.5m

Length: 7m

Weight: 4000-7000kg

Where it lived: It is found in North America.

When it lived: It was a Late Cretaceous dinosaur that lived 70-65 million years ago.

What it ate: Ankylosaurus was a vegetarian. It had leaf shaped teeth for cutting low lying plants.

Weapon of choice: Its big club. Ankylosaurus had a tail which ended in a club which could reach up to 60cm wide. Tests have shown that the club could easily break bone so T.rex had to watch out.

Weakness: Ankylosaurus had a very small brain even for a dinosaur but it didn’t need a big one. With its armour of spikes and plates, a heavy skull and a large destructive tail club, Ankylosaurus was almost invincible and had little to worry about even from T.rex.


Edmontosaurus skeleton at the Ocford Natural History Museum, UK (Wikimedia)

Edmontosaurus skeleton at the Oxford Natural History Museum, UK (Wikimedia)

Edmontosaurus was one of the most common dinosaurs in America. It walked on two legs but could also walk on all fours and had a mouth packed with hundreds of small teeth except for the front of the jaws which had a beak.

Discovery: It was named in 1917. Two skeletons have been found with skin preserved.

Height: 3.5m

Length: 13m

Weight: 3400kg

Where it lived: Edmontosaurus is found throughout North America.

When it lived: Edmontosaurus lived in the Late Cretaceous of North America, about 76 to 65 million years ago.

What it ate: It ate plants. Bits of conifers have been found in its stomachs such as needles, twigs and seeds.

Weapon of choice: Edmontosaurus was big, probably too big for smaller predators but not so for T.rex. Palaeontologists believe that Edmontosaurus lived in herds and that there was safety in numbers.

Weakness: Too small and with no weaponry, Edmontosaurus was as easy as prey got for T.rex.