Information on Dinosaurs

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How do scientists know whether dinosaur fossils are male or female?

One of the most complete Tyrannosaurus rex fossils in the world is named Sue. But no one really knows whether Sue is a boy or a girl -- the fossil got its name from the paleontologist who found it. As it turns out, figuring out the sex of a dinosaur is harder than it sounds, since the relevant parts of the body are all gone by the time someone finds the bones. But a few scientists have succeeded. Telling the males from the females takes a lot of luck — or the willingness to destroy the bones you're studying.

What's so special about a dinosaur named Leonardo?

When researchers tried to get a fossil named Leonardo out of the ground, they didn't use chisels and brushes to slowly separate stone from bone. Instead, they called in demolition experts to free the entire chunk of rock containing the fossil from the rest of the hill. So why go to so much effort? Leonardo isn't just a skeleton: It's one of only a handful of mummified dinosaur fossils ever discovered. It has skin, muscles, organs and even stomach contents. But scientists have learned more from Leonardo than just what it ate for breakfast the day it died.

Can scientists clone dinosaurs?

If you believe what you see in the Jurassic Park movies and books, cloning dinosaurs is as easy as taking blood from a mosquito and mixing it with DNA from a frog. But reconstructing dinosaur DNA is more like building a ladder to the moon with only enough rungs to reach the top of your house. And it turns out that birds might be a better match for dino DNA than frogs. With recent discoveries of dinosaur mummies and soft tissue in fossils, has it become more likely that scientists could create a dinosaur clone?

How did scientists find soft tissue in dinosaur fossils?

Critics say it might just be pond scum, but paleontologist Mary Schweitzer believes there's soft tissue in some dinosaur fossils — if you know where to look. Unfortunately, getting to the bottom of the mystery requires a bath in acid, instead of a trip through a microscope. After a caustic soak, figuring out exactly what the tissue is requires everything from a mass spectrometer to amino acid analysis. How does this discovery change what we know about fossilization? Could it lead to cloning? How can soft tissue last for millions of years — or can it?

Was Tyrannosaurus rex a predator or a scavenger?

Tyrannosaurus rex had gigantic teeth for tearing into meat, and its powerful legs let it chase down its prey. But if you look at it another way, it had powerful jaws for chomping through discarded bones and legs made for endurance rather than speed. The comical smallness of a T. rex's arms might have made it impossible to break a fall while running — or those arms might have been powerful enough to grasp and hold struggling prey. There aren't a lot of healed-over T. rex bites to prove that the tyrant king hunted live animals. But who really survives a T. rex bite?

Which of today's animals lived alongside dinosaurs?

The K-T event, which wiped out the dinosaurs about 65 million years ago, didn't leave behind a barren, lifeless landscape. Many of the plants and animals that live on Earth today have ancestors that survived the event. Sometimes, those ancestors looked and acted a lot like their modern counterparts. Take crocodiles as an example -- toothy, crawling crocodilians have been around for about 220 million years. The gingko tree's oldest relatives started spreading their leaves 270 million years ago. What else walked, flew, swam or grew along with the dinosaurs?

How Saber-Toothed Cats Worked

Several types of saber-toothed cat have lived during Earth's history. The most famous is Smilodon fatalis, which lived during the last ice age and became extinct about 10,000 years ago. Smilodon had the shape of a big cat combined with the bulk of a bear, and it killed its prey by going for the belly or throat. But the sabertooth didn't spend its entire life with teeth as long as a man's hand. Like most mammals, it lost its first set of teeth, meaning young saber-toothed cats spent some time without their infamous canines.

Could dinosaurs swim?

Most cats don't swim by choice. But if one falls into the water, it can usually swim well enough to try to make its way out again, which is also the case for many other animals. Did this rule of thumb hold true for dinosaurs, or did some steer clear of water at all costs? Finding the answer is easier said than done — there aren't any eyewitnesses, and swimming dinosaurs didn't leave much evidence behind. But researchers have found a few clues about whether dinosaurs took to the water.

Did dinosaurs have feathers?

A Tyrannosaurs rex sporting the vivid plumage of a toucan or a macaw might seem comical, instead of menacing. But there's some evidence to suggest that dinosaurs built like T. rex — ones that ate meat and walked on two legs — had feathers. These ranged from tufts of down to orderly quills with vanes and barbs. A bigger question is exactly what dinosaurs used their feathers for. Was it to keep warm, or was it to fly? Does the existence of feathered dinosaurs strengthen the connection between them and birds?

How did dinosaurs leave tracks in solid stone?

Dinosaur footprints are impressive. Sometimes, they're big enough for an adult to sit in, and there are fossil trackways that lead straight up vertical cliffs. But the process of making these tracks was as simple as a day at the beach. Preserving the footprints for millions of years is trickier. What had to happen for a dinosaur's footprints to harden into stone — and for people to find the tracks today? And what do dinosaur footprints tell us about how these extinct animals lived and behaved?