The Cretaceous Period
A few dinosaurs of the Cretaceous Period

Tyrannosaurus (say tie-RAN-oh-SAW-rus). The name means 'tyrant lizard'. It is probably the most famous of all the dinosaurs!

Tyrannosaurus lived about 65 million years ago in the late Cretaceous period (not the Jurassic as many people think). It was a fierce carnivore (meat-eater) that stood up to 5 metres tall. It was about 14 metres long and weighed up to 5 tonnes.

Tyrannosaurus was the largest of the 'lizard-hipped' dinosaurs in the group known as theropods, which walked on two back legs. It was a fierce predator with a powerful tail, large head and tiny two-fingered arms that were probably extremely strong. They were too short to reach the mouth, but were probably used as meat hooks.

When it opened its mouth wide, the gap was 1 metre. The massive mouth had jaws 1.2 metre long, lined with huge, curved serrated teeth. Serrated means they had grooves that made them sharper for cutting, not chewing. Tyrannosaurus swallowed its prey in huge chunks, probably able to gulp about 70 kgs in one swallow.

Fossils show that Tyrannosaurus fought each other, as there are clear tooth marks as evidence.

Anatotitan (say an-AT-oh-TITE-an)
Its name means 'Giant Duck'. It lived about 67 to 65 million years ago in the Late Cretaceous period.

Anatotitan was a 'bird-hipped' dinosaur from the group known as the duck-billed dinosaurs or hadrosaurs. The front of the jaw formed a long, wide beak, with hundreds of teeth at the back lining the cheeks.

Anatotitan had long, powerful back legs with three hoof-like toes. It had small front limbs, with a mitten-like covering on its hands. It stood on all fours to graze, but it could rear up on its hind legs. It had a strong tail and neck.

It was about 13 metres long and weighed up to 5 tonnes.Fossils have been found in the USA.

Parasaurolophus (say PA ruh SAW rul oh fuss)
It is a member of a group of duck-billed dinosaurs known as hadrosaurs. Some hadrosaurs, such as parasaurolophus, had large, hollow crests on their heads and are known as lambeosaurs.

Palaeontologists are not sure what the crest was used for. Some believe it was a way they could recognise each other. However, the crest is full of passages that connect with the respiratory system, suggesting that it was a way the animal coped with heat. Others believe that the passages in the crest help echo the sounds the animal made.

Torosaurus (say TOR-oh-SAW-rus)
The name means 'Bull lizard'. Torosaurus was a 'bird-hipped' dinosaur from the group known as the horn-faced dinosaurs, or ceratopsians and lived in what is now the USA and Canada.

It was up to 8 metres long, weighing about 7 tonnes. It was a herbivore (plant-eater), and was apparently quite sociable. It had a powerful beak that could deal with tough vegetation, including branches. Its back legs were longer than its front legs.

Its skull was 2.6 metres long, including its long crest. It is the largest known skull of any land animal. It had two horns on its forehead, probably for defence and to house huge muscles needed for eating tough vegetation. There are two holes in the crest that would have been covered with skin. Possibly when the animal was courting a partner, the skin over the holes would change colour.

Gallimimus (GAL-ih-MIME-us) moved on its two back legs. It had a beak and was toothless. It had long fingers. It probably ate plants and seeds as well as insects, grubs and other meat.

Ankylosaurus (ang-KIE-low-SAW-russ) was about 9 metres long and weighed about 6,000 kg. It was a herbivore. It was coverend in huge bony plates embedded into its skin. This protection is similar to that of a modern crocodile or armadillo. There was a heavy club at the end of its tail, which it could swing from side to side.

Giganotosaurus (JEE-gah-no-toe-SAW-russ) was one of the largest carnivores, bigger and faster than tyrannosaurus rex. The biggest carnivore now appears to be spinosaurus. It was around 13 metres long and weighed about 13 tonnes. It had a very small brain for its size.

Triceratops (try-SERRA-tops) had between 400 to 800 teeth, but only some were in use at any time and were replaced when they wore out. It was a plant eater. It was about 8 metres long, 3 metres tall and weighed up to 10 tonnes. Its enormous skull alone weighs up to almost 3,000 kg! The backward leaning neck frill could grow to almost 3 metres. Its three horns were used in defence.

Olorotitan (oh-LOW-roe-tie-tan) was a duck-billed dinosaur, although its neck was longer than most others. It had a tall, pointed crest on its head, probably colourful when attracting a mate.

Utahraptor (you-TAH-rap-tor) long grasping hands and big claws on its feet. The toe joints were enlarged so that it could raise the big claw upwards and backwards while running, then flex it forward to use in attack. It had big eyes.

Pachycephalosaurus (PACK-ee-sef-uh-low-SAW-russ) had a 20cm thick skull, ringed by bony bumps. It is believed that it had a thick body, five-fingered hands and moved on its hind legs. It was one of the last dinosaurs in existence.

If you use any part of this, acknowledge it in your bibliography like this:
Sydenham, S. & Thomas, R. The Cretaceous Period [Online]

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updated October 2013©