Cretaceous Period Facts

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.

Herd of Troodon dinosaurs

Continental Shifts

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 freezing during winter.

Quetzalcoatlus, not a dinosaur but a flying reptile called a pterosaur, appeared during the Cretaceous and was the largest animal to ever fly with a wingspan of up to 12 metres. Three of stars from the misleadingly-named Jurassic Park were also present during the Cretaceous; the dinosaurs Triceratops, Tyrannosaurus rex and Velociraptor.

Tyrannosaurus rex fossilised skull

Tyrannosaurus rex fossilised skull

Tyrannosaurus Rex

If there's one dinosaur that everyone's heard of, it's Tyrannosaurus rex. The "tyrant lizard king" was a terrifying predator who evolved during the late Cretaceous and grew to 12 metres in length. It weighed around 5 tonnes and could open its massive jaws an eye-watering 1 metre wide.

Their strong banana-length teeth, weren't just capable of ripping flesh. They could crunch through bone, too. However, T. rex wasn't all brute force. It had acute, binocular eyesight, sensitive hearing and a highly developed sense of smell.

Originally, T. rex's arms were thought to be weak and useless, and at first glance they don't look like they could be much use. Now, palaeontologists believe there's evidence that these arms were incredibly strong, with nearly opposable fingers. No one's quite sure what T. rex used his strong little arms for, though!

Velociraptor

Compared to T. rex, Velociraptors ("quick plunderer") were very much a lightweight at just 1.8 metres in length and weighing between 7kg and 15kg. The "raptors" in Jurassic Park were portrayed at more than twice their actual size, and resembled a dinosaur more like the closely-related Deinonychus. It is also a universal belief that they would have been covered in feathers.

Triceratops

Triceratops ("three-horned face") is the most famous of the horned dinosaurs, and a firm favourite with children. This late Cretaceous animal grew to around 9 metres in length and weighed up to 10 tonnes. As well as three deadly horns, Triceratops had an impressive bony frill behind its head. Palaeontologists believe this could have been used in courtship or in ritual combat with rivals, like rutting deer. Triceratops was a herbivore, using it's beak to gather tough vegetation.

ALthough T. rex probably didn't run, it would have been too heavy, there is a suggestion that the tank-like Triceratops may have been able to gallop like a rhinoceros.

Feathered dinosaur fossil

Feathered dinosaur fossil

Flying

Pterosaurs, 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 descendants of dinosaurs, the birds.

Birds had evolved from the theropod group of dinosaurs, which included bipedal predators such as Velociraptor and T. 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.

Did the dinosaurs die due to a meteor impact?

Did the dinosaurs die due to a meteor impact?

Extinction

We don't know for sure what caused it but at the end of the Cretaceous there was a mass extinction in marine and terrestrial life. Some reptiles and early mammals survived, but dinosaurs, except for birds, of course, became extinct.

Some scientists believe that an increase in volcanic activity, together with the effects of the shifting continents, caused profound climate change on Earth, while others believe that a massive extraterrestrial object hit the planet. One such theory suggests that an asteroid crashed into Chicxulub in Mexico, throwing up a huge dust cloud that obscured the sun, triggering climatic changes.

Whatever the explanation, the age of the dinosaur was over.