New simulations calculated T. rex speed from the motion of its swaying tail, finding that the massive dinosaur was a mighty slow walker.
The Cretaceous, the last and longest period of the dinosaur age, lasted from about 145.5 million to about 65.5 million years ago. During the Cretaceous, mammals were small, about rat size, and the land was ruled by dinosaurs, including the duck-bills (hadrosaurs), horned dinosaurs (Triceratops), long-neck sauropods (Dreadnoughtus) and the tyrannosaurs (Tyrannosaurus rex). When the 79-million-year-long period ended, largely because of a 6-mile-wide (10 kilometers) asteroid slamming into the Yucatan Peninsula, about 80 percent of all animal species went extinct, including the non-avian dinosaurs.
Mosasaurus was one of the largest members of the mosasaur family, which were the top predators in the oceans during the age of dinosaurs.
Around 120 million years ago, tarantulas first appeared on the Gondwana supercontinent in what is now the Americas, and then dispersed into Africa, Australia and India.
New analysis of the ancient crocodylian Deinosuchus confirms that this apex predator had jaws and teeth that were powerful enough to subdue massive dinosaur prey.
The death strike of a Cretaceous "hell ant" from 99 million years ago is preserved in amber, revealing how these demonic-looking ants hunted.
Buckyballs are geometric shapes previously only seen in nature at the molecular scale. Scientists recently found them in marine animals dating to the Cretaceous.
Cryodrakon boreas, a newly described species of giant pterosaur, was recently identified from fossils found in Canada.
Paleontologists have discovered the remains of an ancient Loch Ness Monster look-alike in freezing Antarctica. And just like the legendary Nessie, it wasn't the runt of the litter.
This 92-million-year-old tyrannosaur was so small, it was only slightly larger than the skull of its mighty relative, Tyrannosaurus rex.
An ancient crab that lived during the dinosaur age was so strange, paleontologists are calling it the platypus of the crab world.
The partial skeleton of a baby Tyrannosaurus rex is for sale on eBay for nearly $3 million. Paleontologists are furious about it.
A fossil site in North Dakota preserves a unique snapshot of the minutes after an asteroid struck Earth around 66 million years ago.
What happened after the Cretaceous-ending asteroid struck Earth? A new fossil site may have answers.