Cretaceous Period dinosaurs were many and varied. But they were also doomed. A mass extinction event at the close of this period spelled the end for dinosaurs. Before they bowed out, however, the dinosaurs gave us a truly memorable beast - Tyrannosaurus rex.

Familiar world?
During the early Cretaceous, there were two large continents, Gondwana to the south (comprising South America, Africa, peninsular India, Australia and Antarctica) and Laurasia to the north (comprising North America, Europe and Asia). By the end of the period, these vast landmasses had sub-divided and moved much closer to their present positions. Australia was still connected to Antarctica, though, and India had not yet joined Asia. Overall, it was one of the warmest times in Earth's history, except for the polar latitudes, where scientists believe temperatures dropped below 0 degrees Centigrade during winter.

Enter the king
If there's one dinosaur that everyone's heard of, it's Tyrannosaurus rex ("tyrant lizard king"). This terrifying predator evolved during the late Cretaceous and grew to 12 metres. It weighed around 5 tonnes and could open its massive jaws an eye-watering 1 metre wide. Those jaws, with their strong teeth, weren't just capable of ripping flesh. They could crunch through bone, too! But Tyrannosaurus wasn't all brute force. It had acute, binocular eyesight, ultra-sensitive hearing and a highly developed sense of smell that may have helped it locate dead animals it could scavenge, as well as live prey. Like Allosaurus from the Jurassic Period, it seems that Tyrannosaurus may also have looked after its young.

Killer speed merchant
Compared to Tyrannosaurus, Velociraptor ("quick plunderer") was a lightweight at just 1.8 metres and 7kg - 15kg. But what Velociraptor lacked in size it made up for in ferocity and killing efficiency. And speed. Velociraptor could reach speeds of 64kph, using its tail as a counterbalance on tight turns. In addition to a mouthful of razor-sharp teeth, Velociraptor had huge claws on its feet and hands. It used these to climb up larger prey. As if one Velociraptor on its own wasn't enough, these vicious late Cretaceous killers hunted in packs. And we all know how scary that can be from watching Jurassic Park...

Don't call me frilly
Triceratops ("three-horned face") is the most famous of the horned dinosaurs. This late Cretaceous animal grew to around 9 metres and weighed up to 10 tonnes. As well as three deadly horns, Triceratops had an impressive bony frill behind its head. Palaeontologists believe this was used in courtship and in ritual combat with rivals. Triceratops was a herbivore. Its jaws ended in a quasi-beak that would have helped it gather tough vegetation. Palaeontologists have established that many horned dinosaurs were herding animals but no Triceratops fossils have ever been found together. It seems that Triceratops was a bit of a loner.

Up, up and away
The skies above late Cretaceous dinosaurs were busy. Pterosaurs, huge flying reptiles with wingspans of up to 12 metres, had once been numerous but were on the decline during the late Cretaceous. Their place was being taken by direct descendents of dinosaurs - birds. Birds had evolved from the theropod group of dinosaurs, which included bipedal predators such as Velociraptor and Tyrannosaurus rex. By the late Cretaceous, birds were widespread in forests and mudflats. Some resembled modern birds, such as curlews and sandpipers. There was even a forerunner of today's parrot family.


The great extinction
We don't know what caused it but, at the end of the Cretaceous, there was large-scale extinction in marine and terrestrial life. Other life-forms, including reptiles and mammals, survived but dinosaurs - except for birds, of course - became extinct. Debate over the cause of this mass extinction is intense. Some scientists believe that an increase in volcanic activity, together with the effects of the shifting continents, caused profound climate change on Earth. Another theory is that a massive extraterrestrial object hit the planet, throwing up a huge dust cloud that obscured the sun, triggering climatic changes. Whatever the explanation, the age of the dinosaur was over.

Quick dino-facts

Traditionally, the arms of Tyrannosaurus were thought to be weak and useless. Now, palaeontologists believe there's evidence that these arms were strong, with nearly opposable fingers. No one's sure what T. rex used his strong little arms for, though!

Much of the evidence on the diet of dinosaurs comes from the study of their fossilised dung.

The Velociraptors in Jurassic Park were portrayed at twice their actual size.