The Rise of Meat-Eating Dinosaurs Is More Complicated Than We Thought
By Riley Black/Smithsonianmag.com
The names alone are imposing. Take Tyrannosaurus, the tyrant lizard; Torvosaurus, the savage lizard; or Giganotosaurus, the giant southern lizard. These monstrous carnivores dominate our imaginations, movies and museum halls, and no natural history museum nor Jurassic Park film would be complete without a towering predatory dinosaur tall enough to look into a second-story window.
But all these giants were latecomers in the dinosaur saga. For tens of millions of years, even as other dinosaur species grew to huge sizes, 40-foot carnivores weren’t around. How, then, did the meat-eaters rise to the top of the food web in the Age of Dinosaurs? The answers are just starting to spill out of the stone.
Where Carnivorous Dinosaurs Came From
First, a quick history lesson. The earliest dinosaurs arose about 235 million years ago during the Middle Triassic. They didn’t look much like modern favorites Triceratops or Spinosaurus. Instead, these lanky creatures didn’t get much bigger than a German shepherd. The current spate of evidence suggests they were omnivorous. These first dinosaur populations varied and evolved into new forms including the ancestors of the long-necked sauropods and a group called the theropods, which includes all known carnivorous dinosaurs.