Nothosaurus, a medium-sized sauropterygian from the Triassic. (Credit Gabriel Ugueto)

The giant Cambrian worm was a terrifying predator, and could grow to 2 metres. (Credit DeviantArt/HodariNundu)

The diversity of Pterosaur beaks. (Credit Julio the Artist 🦕🌿)

Stagonolepis robertsoni is an extinct, herbivorous crocodilian that measured 3 metres in length. (Credit Mark Witton)

Deinocheirus was a huge herbivorous theropod from the late Cretaceous. They measured 11 metres long & weighed 6 tonnes. (Credit Andrey Atuchin)

Chriacus is a prehistoric mammal that lived 60 million years ago. They measured a metre long & weighed 7kg. (Credit C B Pease)

Hatzegopteryx is estimated to have a wingspan of 12 metres, rivaling that of the largest pterosaur Quetzalcoatlus. (Credit Julio Lacerda)

Ancient proto-spider with a tail preserved in amber. (Credit University of Kansas)

Echovenator sandersi lived during the Oligocene epoch, around 27 million years ago. It had superb high-frequency hearing to locate prey. (Credit A. Gennari)

The gape width of Smilodon (A) compared to Thylacosmilus (B) showing the extent of the canines within the skull. (Credit Stephen Wroe et al.)

Hurdia was a primitive cousin of insects and other arthropods. (Credit Quade Paul)

Rubeosaurus lived in North America 74.6 million years ago. (Credit Mohamed Haghani)

Eogyrinus attheyi was one of the largest tetrapods of the Carboniferous, at 4.6 metres in length. Like the modern crocodile, it was an ambush predator. (Credit dinoraul 2011)

Dinocephalosaurus was a long necked, aquatic protorosaur from the Triassic Period. They were ambush predators & hunted fish, violently thrashing their neck at prey when they got into the 'strike zone'. (Credit: Prehistoric Wildlife)

Nesodon was a Miocene mammal from South America that measured 1.5 metres at the shoulder.

Pristerognathus was a dog-sized predator that lived during the late Middle Permian in what is now South Africa. (Credit dmitrchel)

The Salish Wool Dog is an extinct breed of dog whose fur was used like a sheep to make clothes. It is the only prehistoric North American animal to be selectively bred.

The snake ancestor that had four tiny legs that gripped prey! (Credit Julius Csotonyi)

Moeritherium was a hippo-like animal that ate soft water vegetation. They are closely related to elephants. (Credit Mehdi Nikbakhsh)

Aegirocassis, a 2-metre giant, filter feeding radiodont from 480 million years ago. (Credit Christopher Chavez)