Early-late Cretaceous, 112-97 million years ago
Spinosaurus was big. Very big. The-longest-flesh-eating-animal-to-ever-walk-the-earth big. Even based on more conservative estimates of about 49 feet in length, it readily beats Giganotosaurus, Carcharodontosaurus, and Tyrannosaurus rex. And according to new research, Spinosaurus was also an able swimmer, snaring prey on land and at sea with its slender, crocodile-like jaws. Scientists have previously proposed that its elaborate sail was used for thermoregulation or sexual display, but based on its newly revised, almost quadrupedal stature, it is now widely accepted that Spinosaurus was just desperately trying to look taller.