Description Life first started in prehistoric seas some 3,000 million years ago, and the strangest forms of life then dominated the Earth. Some of the creatures that swam in the sea crawled up on land, developing and adapting to the conditions the found there. From these early animals evolved the dinosaurs that ruled until suddenly, 64 million years ago, they died out and the Age of Mammals began. The great variety of prehistoric animals and plants have left behind fossil remains that tell us about the history of our planet. The scientific study of these remains shows which creatures have appeared, and often why they disappeared. Packed with stunning illustrations and fascinating details, Prehistoric Life opens up[p an extraordinary world of trilobites, dinosaurs, mammoths, early humans and sabre-toothed cats.