Dinosaurs: Top 10 Questions

November 2012

Thanks to David Varricchio, Assistant Professor of Paleontology, Earth Science Department, Montana State University for the answers.

1: How did the dinosaurs go extinct?

We know some things that occurred about the time dinosaurs went extinct. There were major changes in climate due to a lot of volcanic eruptions that altered the earth's atmosphere and changed temperatures. Also, there is really good evidence that an asteroid hit the earth's surface. These probably contributed to the extinction of dinosaurs. However, if you ask ten different paleontologists why, they will have ten different reasons. (From Cagney at Shadow Hills Elementary School in Boise)

2: How did dinosaurs become fossils?

Bones have a mineral crystal component to them. In some ways, they are like rocks to begin with. Other parts of our bones are filled with blood and nerve tissue. That material gets eaten by bacteria and rots away, leaving spaces. Through time, water under ground percolates through the rock and deposits other minerals and crystals that grow inside the spaces in that bone. (From Devon at Maranatha Christian School in Boise)

3: How long did dinosaurs live?

Dinosaur bones record growth lines, like the trees have growth rings. You can look at trees and count how old the tree is. In the same way, you can look at dinosaur bones and get an estimate of their age by looking at the growth lines. For the big dinosaurs, they lived 10, 20, maybe even 50 years. (From John at St. Mary's School in Moscow)

4: Are dinosaurs related to birds or reptiles?

You can think of dinosaurs and birds as really belonging to the reptile group. We typically think of them, as well as turtles, lizards, snakes, and crocodiles, as belonging to that group. We can say that birds are dinosaurs, and that dinosaurs and birds are reptiles. (From Ben at Clearwater Elementary School in Kooskia)

5: How many species of dinosaurs are there?

We can only guess at how many there were. When we look at the rocks that dinosaurs are found in, we probably only see a small sample of all the dinosaurs that once lived. So far, scientists have named about 600 species, but it's estimated that there may have been 2,000 or 3,000 dinosaurs through the whole Mesozoic Era. (From Dani at Lena Elementary School in Moscow)

6: Why does a small mammal survive, but not the dinosaurs?

Some people think that the small animal may have been able to find shelter, such as crawling into a burrow, when the asteroid hit. Other small animals, like turtles and frogs, may have swum down to the bottom of the pond and hidden in the mud for a few months. Big animals require lots of food and space, whereas smaller animals can get by on very little. (From Nicole at Pine Forrest Elementary School in North Carolina)

7: In what era and what kind of dinosaurs lived in Idaho?

We have rocks in eastern Idaho that are from 100 million years ago. That's the Cretaceous period. One dinosaur that has been found is the oryctodromeus. It was about the size of your typical dog, not a very big dinosaur. It ate plants. We've found teeth from some carnivorous dinosaurs, maybe raptors. There may be a big ductile type animal as well. Also, even though we have no bones, we do have eggs from what may be a big giant oviraptor. (From Parker at Highlands Elementary School in Boise)

8: How many bones are there in a velociraptor?

Velociraptors had a lot of bones, probably in the neighborhood of about 250. (From Jack at McDonald Elementary School in Moscow)

9: Which dinosaurs had feathers?

It's only been a few years since we've found feathers on dinosaurs. So far, the most common are the meat-eating dinosaurs, particularly the smaller ones. They are closely related to birds. Recently, feathers have been found from tyrannosaurus relatives. (From Ben at Horizon Elementary School in Boise)

10: How many teeth did they have?

They had about 60 teeth in their jaws at one time. For each tooth that you could see, they had a tooth that was ready to replace it. So in their smile, you would see about 60 teeth, although there were probably about 120 teeth total, half that you wouldn't have been able to see. (From Kendall at Camelot Elementary School in Lewiston)

September 2008

Thanks to David Varricchio, Assistant Professor of Paleontology, Earth Sciences Department at Montana State University for the answers.

1: Why do dinosaurs have such complicated names?

Historically we have tried to standardize the name of each dinosaur by using "Latinized" names so that any one around the world can understand them. So if you speak Chinese or French or German, for instance, we can all settle on or agree upon one single name. Because of the Latin names, however, the words can become mouthfuls. (From Stuart in Mrs. McCamish-Cameron's class at Cynthia Mann Elementary School in Boise)

2: Were there cavemen when dinosaurs lived?

It is thought that cavemen didn't evolve until long after the dinosaurs went instinct. Evidence shows that dinosaurs became extinct 65 million years ago and the first humanlike people show up about three - or maybe five - million years ago. (From Ethan in Mrs. McCamish-Cameron's class at Cynthia Mann Elementary School in Boise)

3: What is the most recent dinosaur found?

We don't know the exact answer to that. There have been a number of dinosaurs described this year alone; there's a new carnivorous dinosaur that has been named basically because it was unique in having a variety of air sacks within the bones of the skeleton. It is thought that 600 different types of dinosaurs or more have been found or described. (From Paige in Mrs. Boehne's class at McDonald Elementary School in Moscow)

4: What kind of dinosaurs lived on each continent?

When dinosaurs first evolved all the continents were thought to have been connected together. As you go through the history of dinosaurs they evolve differently in their groups as those continents break up. Early in the history of dinosaurs, the dinosaurs you could find in North America you could also find in Africa. But by the end of the dinosaur period (about 70 million years ago), there are unique dinosaurs to each continent. So we would find a unique set of dinosaurs in Idaho or Montana than we would in South America. (From Hanna in Mrs. Chris's class at Northwest Children's Home in Lewiston)

5: Are dinosaurs related to birds or reptiles?

Crocodiles among reptiles are closely related to dinosaurs. They're sort of the cousins of dinosaurs. Birds have evolved from the carnivorous group of dinosaurs; scientists think of them as actually belonging to the dinosaur group. (From Ben in Mrs. Fryer's class at Clearwater Valley Elementary School in Kooskia)

6: What was the average weight of a Tyrannosaurus, or "T-Rex"?

They were somewhere in the neighborhood of three to maybe six tons, similar to a large elephant. (From Isabella in Mrs. McCoy's class at Donnelly Elementary School in Donnelly)

7: Have any of the giant meat eaters ever been found to have feathers?

We have evidence now for a wide variety of meat-eating dinosaurs as having feathers. They were much smaller than T-Rex. We have skin impressions of T-Rex and its close relatives, so the big animals in that group had kind of scaly reptile-like skin. But they had the capability of producing feathers. (From Ben in Mrs. Gris's class at Horizon Elementary School in Boise)

8: What was the largest bone ever found?

There are some ribs of big sauropod dinosaurs that are 9 or 10 feet long and I would say the most massive bone is the thigh bone, the femur, and those are maybe seven or eight feet tall. (From Jack in Mrs. Rice's class at Mill Creek Elementary School in Middleton)

9: What was the biggest ocean-dwelling dinosaur?

Scientists separate dinosaurs from some of the big reptiles of the same time that lived in the ocean. So for dinosaurs in a very sort of specific sense or scientific sense, dinosaurs pretty much only lived on land, and that's kind of important to how we define dinosaurs. When they were alive though there were big reptiles, marine reptiles, and some of those got quite large, reaching almost 100 feet in length. You can think of them as comparable to some of the whales today. (From Bailey in Mrs. Schweitzer's class at Riverside Elementary School in Boise)

10: What's the biggest dinosaur, what's the smallest?

The smallest is the microraptor. Dinosaurs ranged from the size of a chicken to animals that were 100 feet long, maybe even longer, maybe 120 feet, and many tons in size. Some people even say 10, 20, or 40 tons in weight! Some of the biggest dinosaurs were the sizemasaurus, which means earth-shaking reptile, or the argentinasaurus, a really large one as well. (From several questioners around the state)

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