Ancient Worlds

Just like those today, the oceans of the Permian period, 250 million years ago, were teeming with life. Here, a Helicoprion-- a shark-like fish with a whorl of teeth in its lower jaw-- lunges out of a coral reef to ambush an ammonite, while a pair of squid-like belemnites swim away in the foreground.  Despite its appearance, Helicoprion was not a true shark, but was related to modern-day chimaeras, or ratfish. 

80 million years ago, North America was split in half by a huge inland ocean called the Western Interior Seaway. This was home to a frightening array of aquatic predators, and the most fearsome of all was Tylosaurus, a giant ocean-dwelling lizard. Overhead flew seabirds like Ichthyornis and pterosaurs like Pteranodon, which dove into the water to catch fish-- and occasionally get eaten by the killers lurking below. 

Between 65 and 66 million years ago, the Mesozoic era came to an end. This arguably happened at the climax of the age of dinosaurs, when many of the most famous and spectacular species lived-- none more so than Tyrannosaurus, which was the apex predator of western North America during this period. Here it is shown with a number of other animals that would have lived in what is now Texas at the very end of the Mesozoic. 

65 million years ago, Romania was an island separated from the rest of Europe. There were no large carnivorous dinosaurs here, so instead the top predator was the giant pterosaur Hatzegopteryx, which had a wingspan of over 35 feet. Hatzegopteryx would have preyed on plant-eating dinosaurs such as the birdlike Balaur. Also present were sauropods no bigger than horses, which had evolved into dwarf forms due to the limited food available on the island, as well as smaller pterosaurs like Eurazhdarcho and crocodiles like Allodaposuchus.

China in the Jurassic period was home to some of the largest animals in the world. Here, a group of Limusaurus-- herbivorous relatives of predatory theropod dinosaurs-- watch a pair of Mamenchisaurus browsing on the tops of trees. At up to 50 feet, Mamenchisaurus had possibly the longest neck in the animal kingdom. Overhead fly a pair of Agustinaripterus, a pterosaur (flying reptile) about the size of a large hawk. 

The deserts of Mongolia are famous for their dinosaur fossils, many of which belong to the maniraptor, or bird-like, dinosaur group. Both the predatory Velociraptor in the foreground and the two giant plant-eating Therizinosaurus are members of this group. Because they  were so much like birds, scientists think these dinosaurs and others like them had feathers. Both of these animals lived in Mongolia about 72 million years ago, While Velociraptor was a predator, Therizinosaurus was an herbivore. 

300 million years ago, bugs were much bigger than they are today! The Carboniferous coal swamps were home to truly gigantic arthropods, such as the two-foot scorpion Pulmonoscorpius, the dragonfly-like "griffinfly" Meganeura, and the eight-foot millipede Arthropleura. Giant amphibians, like Proterogyrinus also thrived during this time. Not all Carboniferous creatures were enormous, though; the early spider Arthrolycosa was about the size of a tarantula. 

Australian wildlife might have a scary reputation now, but that's nothing compared to what roamed the Land Down Under 50,000 years ago. The 20-foot monitor lizard Megalania was Australia's apex predator, preying on the giant flightless bird Genyornis and the hippo-sized wombat relative Diprotodon. Weighing up to two tons and armed with a venomous bite, Megalania had no enemies until humans entered its world.