The largest ever camel was the Syrian camel which grew to 4 metres in height! (Credit Doubutsu-no-kuni)

Nigersaurus had a jaw that was wider than the rest of its skull, perfect for munching vegetation close to the ground. It had over 500 teeth, in multiple rows which could grow back every two weeks. (Photo dinosaurpictures.org)

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

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

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

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.

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

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

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)

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)

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

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

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

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

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