12 Frequently Asked Dinosaur Questions

Why were dinosaurs so big? What did they eat, where did they live, and how did they raise their young? The following are a dozen of the most frequently asked questions about dinosaurs with links to the best answers for further exploring. Learning about dinosaurs can be tricky—there are so many of them, and there's so much to know—but it's a lot easier when the details are portioned out in a logical way.

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What Is a Dinosaur?

Close-up of the skull of a <I>Tyrannosaurus rex</I> from the late Cretaceous period — *Tyrannosaurus rex* is one of the most well-known of all dinosaurs.
Wikimedia Commons

People sling the word "dinosaur" around an awful lot, without knowing precisely what it means—or how dinosaurs differed from the archosaurs that preceded them, the marine reptiles and pterosaurs with which they coexisted, or the birds to which they were ancestral. In this article, you'll learn what experts really mean by the word "dinosaur."

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Why Were Dinosaurs So Big?

Close-up of the face of a <I>Nigersaurus</I> plant-eater, showing its pebbly skin and bony spiked spine — The plant-eater *Nigersaurus* or (Niger reptile) from the Cretaceous period was about 30 feet long and weighed 4 tons.
Wikimedia Commons

The biggest dinosaurs—four-legged plant-eaters like Diplodocus and two-legged meat-eaters like Spinosaurus—were bigger than any other land-dwelling animals on Earth, before or since. How, and why, did these dinosaurs attain such enormous size? Here's an article explaining why dinosaurs were so big.

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When Did Dinosaurs Live?

This diagram shows the Mesozoic Era broken into the three periods, beginning with the most recent at the top: Cretaceous, Jurassic, and Triassic.

ThoughtCo / UCMP

Dinosaurs ruled the Earth longer than any other terrestrial animals, all the way from the middle Triassic period (about 230 million years ago) to the end of the Cretaceous period (about 65 million years ago). Here's a detailed overview of the Mesozoic Era, the period of geologic time comprising the Triassic, Jurassic, and Cretaceous periods.

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How Did Dinosaurs Evolve?

An illustration of the meat-eating <I>Tawa hallae</I> dinosaur from the Late Triassic period — *Tawa hallae* is considered an evolutionary link between primitive carnivores and modern birds.
ThoughtCo / Nobu Tamura

As far as paleontologists can tell, the first dinosaurs evolved from the two-legged archosaurs of late Triassic South America (these same archosaurs also gave rise to the very first pterosaurs and prehistoric crocodiles). Here's an overview of the reptiles that preceded the dinosaurs, as well as the story of the evolution of the first dinosaurs.

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What Did Dinosaurs Really Look Like?

An illustration of the face of a <I>Jeyawati</I> dinosaur with pebbly skin, bony ridge back, and flap over its mouth — The face of the plant-eating *Jeyawati* dinosaur from the Cretaceous period.
ThoughtCo / Lukas Panzarin

This might seem like an obvious question, but the fact is that depictions of dinosaurs in art, science, literature, and movies have changed radically over the last 200 years—not only how their anatomy and posture are depicted but also the color and texture of their skin. Here's a more detailed analysis of what dinosaurs really looked like.

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How Did Dinosaurs Raise Their Young?

Two hands gently hold a large titanosaur egg — A titanosaur egg from one of the largest dinosaurs that ever lived. Getty Images

It took decades for paleontologists just to figure out that dinosaurs laid eggs—they're still learning about how theropods, hadrosaurs, and stegosaurs raised their young. First things first, though: Here's an article explaining how dinosaurs had sex and another article on the subject of how dinosaurs raised their young.

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How Smart Were Dinosaurs?

The head of the carnivorous <I>Troodon</I>, a small bird-like dinosaur green eyes and smooth, snake-like skin — *Troodon* is considered to be among the smartest dinosaurs because it had a large brain for its small size.
ThoughtCo

Not all dinosaurs were as dumb as fire hydrants, a myth that has been perpetuated by the spectacularly small-brained Stegosaurus. Some representatives of the breed, especially feathered meat-eaters, may even have attained near-mammalian levels of intelligence, as you can read for yourself in "How Smart Were Dinosaurs?" and the "10 Smartest Dinosaurs."

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How Fast Could Dinosaurs Run?

An <I>Ornithomimus</I> (bird mimic) with feathers, wings, and long tail forages in a field with its tiny offspring — An *Ornithomimus* (bird mimic) may have been able to run 43 mph.
ThoughtCo / Julio Lacerda

In the movies, meat-eating dinosaurs are portrayed as speedy, relentless killing machines, while plant-eating dinosaurs are fleet, stampeding herd animals. The fact is, though, that dinosaurs differed enormously in their locomotive abilities, and some breeds were faster than others. This article explores how fast dinosaurs could really run.

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What Did Dinosaurs Eat?

A photo of a fern-like, seed-bearing cycad with a couple of large cones — A fern-like, seed-bearing cycad with a couple of large cones—food in prehistoric times. Wikimedia Commons

Depending on their proclivities, dinosaurs pursued a wide variety of diets: Mammals, lizards, bugs, and other dinosaurs were favored by meat-eating theropods, and cycads, ferns, and even flowers figured on the menus of sauropods, hadrosaurs, and other herbivorous species. Here's a more detailed analysis of what dinosaurs ate during the Mesozoic Era.

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How Did Dinosaurs Hunt Their Prey?

An illustration of the <i>Deinocheirus mirificus</i> (Greek for terrible hand) showing its 8-inch arms and 8-inch claws — The 8-inch arms and 8-inch claws on the omnivorous *Deinocheirus mirificus* (Greek for terrible hand) would have been perfect for gathering plants and catching fish.
ThoughtCo / Luis Rey

The carnivorous dinosaurs of the Mesozoic Era were equipped with sharp teeth, better-than-average vision, and powerful hind limbs. Their plant-eating victims evolved their own unique set of defenses, ranging from armor plating to spiked tails. This article discusses the offensive and defensive weapons used by dinosaurs, and how they were employed in combat.

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Where Did Dinosaurs Live?

A lush riparian forest is where dinosaurs would have congregated. Wikimedia Commons

Like modern animals, the dinosaurs of the Mesozoic Era occupied a wide range of geographical regions, from deserts to tropics to polar regions, across all the Earth's continents. Here's a list of the 10 most important habitats prowled by dinosaurs during the Triassic, Jurassic, and Cretaceous periods, as well as slideshows of the "Top 10 Dinosaurs by Continent."

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Why Did Dinosaurs Go Extinct?

An aerial view of Arizona’s Barringer Meteor Crater is a small-scale example of the underwater Chicxulub crater in the Yucatan Peninsula—the meteor responsible for the K-T extinction event. U.S. Geological Survey

At the end of the Cretaceous period, dinosaurs, pterosaurs, and marine reptiles seemed to have disappeared off the face of the Earth virtually overnight (though, in fact, the process of extinction may have lasted for thousands of years). What could have been powerful enough to wipe out such a successful family? Here's an article explaining the K-T extinction event, as well as "10 Myths About Dinosaur Extinction."