Zoom Dinosaurs DINOSAUR QUESTIONS

Q: What is the height of an Apatosaurus?
from ??; May 31, 1998

A: Apatosaurus was about 15 feet (4.6 m) tall at the hips. The height to the top of its head is not used because the dinosaur could assume may different stances. For more information on Apatosaurus, click here.

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Q: What were the commonest dinosaurs which lived England? EDWARD (age 7)
from Edward, England; May 31, 1998

A: Some of the most common dinosaur fossils found in England are: Iguanodon, Anatosaurus, Cetiosaurus, Dryosaurus, Hylaeosaurus, Megalosaurus, Scelidosaurus, Thecodontosaurus, and Hypsilophodon.

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Q: Where do dinosaurs come from?
from David, UT, USA; May 30, 1998

A: Dinosaur eggs.

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Q: Im doing a report on trachodon, and I cant find very much info. Please send me all the info you can asap
from ???; May 29, 1998

A: Trachodon (meaning "rough tooth") is a plant-eating dinosaur that is known only from a few teeth found in Montana, USA! It dates from the late Cretaceous period, about 77-73 million years ago. From the teeth, it has been surmised that it was probably a duck-billed dinosaur. It was named in 1856 by Joseph Leidy. There's an interesting page on Trachodon at Dinosauria.com.

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Q: Who/what were the natural enemies of the Pteranodon ?
from Kelly C., Anaheim, CA, USA; May 29, 1998

A: Pteranodon lived during the late Cretaceous period in North America and Europe. Its large predatory contemporaries included Tyrannosaurus rex and Troodon. For more information on Pteranodon, click here.

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Q: Can you please tell me the "How, Who, What, When & Where" of the discovery of the Hypsilophodon? For whatever reason I can't get to that link. Thanks!
from Karrie M., Newark, OH, USA; May 29, 1998

A: Hypsilophodon was first described by Thomas Huxley in 1870 and paleontologists thought that it was quite similar to the modern-day tree kangaroo. For over 100 years, scientist believed that Hypsilophodon lived in trees. In 1974, paleontologist Peter M. Galton's reconstruction of Hypsilophodon showed that there is no evidence for tree-dwelling behavior, and that Hypsilophodon was a terrestrial dinosaur.

Fossils of Hypsilophodon, and many other Cretaceous species (Iguanodon, crocodilians, turtles, fish, insects, mammals, and plants) have been found on the Wealden of southeast England and on the Isle of Wight. About 20 Hypsilophodon fossils were found together on the Isle of Wight (off the southern coast of England).

For more information on Hypsilophodon, click here.

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Q: Did all 330 kinds of dinosaurs have tiny brains?
from Mrs. Leija's 1/2 Multiage class, Estes Park, Colorado, USA; May 28, 1998

A: Yes, to one degree or another. The smartest dinosaurs (the ones with the largest brain:body weight ratio) were the dromaeosaurids. The least intelligent were the sauropodomorpha.
The EQ or Encephalization Quotient is a simple way of measuring an animal's intelligence. EQ is a ratio of the mass of an animal's brain to the mass of its body. Assuming that smarter animals have larger brains to body ratios than less intelligent ones, this helps determine the relative intelligence of extinct animals. In general, warm-blooded animals (like mammals) have a higher EQ than cold-blooded ones (like reptiles and fish).

The primitive dinosaurs belonging to the group sauropodomorpha (which included Massospondylus, Riojasaurus, and others) were among the least intelligent of the dinosaurs, with an EQ of about 0.05. The troodontids (including Troodon) and dromaeosaurid dinosaurs (the "raptors," which included Dromeosaurus, Velociraptor, Deinonychus, and others) had the highest EQ among the dinosaurs, about 5.8.

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Q: What was the Stegosaurus? Was it a vegetarian? And how well did they protect their young?
from Kerri C., Carrboro, NC, USA; May 28, 1998

A: Stegosaurus was a vegetarian about 30 feet long with 2 rows of triangular plates along its back and tail spikes. Its small brain was the size of a walnut, its skull was long and narrow; it had a toothless beak and small cheek teeth. Its head was carried close to the ground. For an information sheet on Stegosaurus, click here.

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Q: what is the weight of Brachiosaurus
from Matt K., Adelaide, Australia; May 27, 1998

A: Brachiosaurus weighed about 80 tons. For more information on Brachiosaurus, click here.

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Q: What dinosaur had the most teeth? Hadrosaurus right! Do dinosaurs hibernate?
from IVI, Adelaide, SA, Australia; May 27, 1998

A: Yes, some hadrosaurs had up to 960 teeth! No one knows if any dinosaurs hibernated, but it is unlikely since the dinosaurs lived during a time when the earth was very warm. The earth only started to cool off toward the end of the Mesozoic.

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Q: How old was the oldest dinosaur? What did it look like?
from Alsahnlaey, Osprey, FL, USA; May 27, 1998

A: The oldest dinosaur yet found is the Eoraptor, which lived in the late Triassic period, roughly 228 million years ago. Very few dinosaurs had evolved yet during this period. For information on Eoraptor, click here.

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Q: Hello Zoom Dinosaur peoples! I like your web page and dinosaurs, especially the T-Rex. That's why im doing a report on the T-Rex. I just wanted to know if the T-Rex was a carnivore or a herbivore or an omnivour. Please give me lots and lots and lots and lots of information as soon as possible because my report is due tomorrow. Thanks a lot and I like your web page. ~Have a nice day~ :fi
from Timothy S., Cerritos, CA, US of A; May 26, 1998

A: T. Rex was a carnivore - a meat-eater. For an information page on T. rex, click here.

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Q: How many different kind of Triceratops are there?
from ???; May 26, 1998

A: There is some disagreement about this. Some paleontologists (notably Ostrom and Welnhoffer, 1990) believe there is one species, Triceratops horridus, with the different "species" representing juveniles, males, and females. Others believe that there are two (C. Forster, 1996), and some think that there are even more species, including: Triceratops horridus, Triceratops prorsus, Triceratops albertensis, Triceratops ingens, Triceratops alticornis, and perhaps others.

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Q: how tall was a edmontosaurus if he was standing on all four legs, who discovered it, and what is the width and length of an edmontosaurus' footprint?
from Jeb H., Texas, USA; May 25, 1998

A: Edmontosaurus was named by paleontologist Lawrence M. Lambe in 1917 from a fossil found in Alberta, Canada. It was about 42 feet long - its height depends on its stance at the time. Almost no one uses height as a measure of most dinosaurs because the dinosaurs could have many stances (especially Edmontosaurus, since it walked on either two legs or on four legs, head up or head down, depending on the activity). I don't have any information on its footprints.

For more information on Edmontosaurus, click here.

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Q: hi ~ !
my name is ivan. I'm a 5th grader from Cerritos California. At school, we are doing a dino project. I need to find info on the dinosaur species: monoclonius. I was wondering if u can assist me in finding / sending me information on that particular species.
thank you for all your help. i like your web page. It's one of my favorite sites.
from ivan, Cerritos, CA, USA; May 25, 1998

A: Monoclonius was a late ornithischian dinosaur, the order of bird-hipped, herbivorous dinosaurs. It was a member of the suborder marginocephalia, and the family of large, horned, frilled, herding herbivores (plant-eaters), the Ceratopsians. It was related to Styracosaurus and Centrosaurus and was first found in the late 1800's and named in 1876. It was a frilled dinosaur about 20 feet (6 m) long), had a large horn on its snout, had 2 small horns near the top of its frill, and had a toothed, horny beak. It had a bulky body, a short, thick, pointed tail, a very large skull. It lived during the late Cretaceous period and may have roamed in herds (like other Ceratopsians, notably Styracosaurus). Monoclonius probably ate cycads, palms, and other prehistoric plants with its tough, toothed beak. It could also chew well with its cheek teeth (like other Ceratopsians, but unlike most other dinosaurs).

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Q: I was told that some dinosaurs were warm blooded. Is that true or is it just a line?
from ??, Brockville, Ontario, Canada; May 25, 1998

A: The debate about whether dinosaurs were hot- or cold-blooded is quite controversial. It used to be assumed that dinosaurs were cold-blooded like their reptile ancestors. Some paleontologists have recently argued that at least some dinosaurs were fast, active, competed against hot-blooded mammals, lived in cool areas, were related to birds, and therefore were endothermic (generating their own body heat, or hot-blooded).

Dinosaurs evolved from cold-blooded animals (the reptiles) and evolved into warm-blooded animals (the birds). All dinosaurs, however, were not the same, and perhaps their physiologies differed also. The huge dinosaurs and the tiny dinosaurs might have used different heat-regulation strategies, just as they used different strategies for other aspect of living. A good argument for this is found among modern mammals. Although warm-blooded, there are some mammals (monotremes, the egg-laying mammals like the duck-billed platypus) whose metabolisms are close to being cold-blooded.

Some dinosaurs seem to have had heat regulating structures on their bodies. For example, Spinosaurus and Ouranosaurus had large sails on their backs, and Stegosaurus had numerous plates. These devices were probably used for the collection and dispersion of heat. This suggests that they needed these structures to regulate their body heat and that they were cold-blooded.

Basically, it's difficult or perhaps impossible to answer this question with today's knowledge. There are a lot of people thinking about this, and we'll be hearing a lot more about it soon.

• Hot-blooded animals (homeotherms) generate heat internally and maintain a relatively constant body temperature (higher than the average temperature of the environment). Examples include the mammals (including people) and birds. A related term is endothermy, meaning that an organism generates their own heat to maintain body temperatures.
• Cold-blooded animals (poikilotherms) have a body temperature that changes with external conditions. Examples include reptiles, who need to sun themselves in the morning to warm up, and then protect themselves in the midday heat. A related term is ectothermy, meaning that an organism uses external heat sources (and heat sinks) to regulate its body temperature.

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Q: how tall was a Edmontosaurus? If you can list some dinosaurs that lived in the same part of the world and the same time period as the Edmontosaurus, i would appreciate it.
from Sid, Columbus, OH, USA; May 25, 1998

A: Edmontosaurus (about 42 feet long - its height depends on its stance at the time) lived during the late Cretaceous period (about 73-65 million years ago) and in the western part of North America (and perhaps the eastern part). Other dinosaurs in this time and place include T. rex, Ornithomimus, Montanoceratops, Corythosaurus, Parasaurolophus. For more of its contemporaries, click here and scroll down to the section on the late Cretaceous in North America. For more information on Edmontosaurus, click here.

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Q: WHAT WAS THE FIRST DINOSAUR TO EVER WALK ON LAND AND WHAT WAS THE FIRST LIVING THING EVER AND HOW LONG AGO DID LAND START FORMING. MY FINAL QUESTION IS WHERE WAS THE FIRST DINOSAUR FOUND AND WHERE MOST OF THE DINOSAURS FOUND
from Adam L., Bronx, NY, USA; May 24, 1998

A: The oldest dinosaur yet found is the Eoraptor, which lived in the late Triassic period, roughly 228 million years ago. Very few dinosaurs had evolved yet during this period. For information on Eoraptor, click here.

The first life forms on earth were single-celled organisms, blue-green algae, that evolved during the Archeozoic Eon 3.9 to 2.5 billion years ago.

The first dinosaurs to be found (Megalosaurus,Iguanodon, and Hylaeosaurus) were found in England in the early 1800's.

The land on earth solidified during the Hadean Eon, 4.6 to 3.9 billion years ago. For more information on the geological eras on earth, click here.

More dinosaurs have been found in western North America than anywhere else. Montana seems to have more discoveries than other places within this area. This is partly because of the large amount of exposed Mesozoic sedimentary rock there and the ease of accessibility to these rocks.

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Q: I need info on dinosaurs that start with the letters Z, W and J. Please help me!!! I really need a picture and information for the following dinosaurs: Zigongosaurus and one with a W as the first letter I need this as soon as possible! Thank you
from ???; May 23, 1998

A: Click here for an information sheet on Zigongosaurus.

Wannanosaurus (named after the Chinese province where its very incomplete skeleton was found) was a tiny homalocephalid dinosaur about 2 feet (60 cm) long. It was a very primitive Pachycephalosaur (related to Pachycephalosaurus and Stegoceras, other dinosaurs with thick skulls that probably engaged in head-butting activities). The homalocephalids had thick, but flat-topped skulls. It was an herbivore (a plant-eater) that walked on two strong legs, had short arms, a stiff tail, and a thick-set body. (Its resembles Pachycephalosaurus , but it was much smaller and its head was much flatter.) It lived during the late Cretaceous period.

Jaxartosaurus was a hadrosaurid (a duck-billed dinosaur) found near the Jaxartes River in Kazakhstan. Only an incomplete skeleton was found. For more information on the duck-billed dinosaurs, click here.

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Q: How do you know what the dinosaur's names were?
from Stacy and Jessie, Grand Ledge, MI, USA; May 22, 1998

A: People name newly discovered dinosaur fossils after they've been found, examined, and it has been determined that they are a new species. The names can reflect characteristics of the dinosaur (for example, Corythosaurus, meaning "helmet lizard," had a helmet-shaped crest on its head), the discoverer or another paleontologist (for example, Lambeosaurus, named for Lawrence Lambe), the place of discovery (for example, Albertosaurus, named for Alberta, Canada, where it was found), or just about anything the namer wants.

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Q: how did dinosaurs die?
from ???; May 22, 1998

A: Most dinosaurs went extinct because they couldn't compete with other species - these extinctions are called background extinctions. For those remaining dinosaurs, extinction came at the end of the Mesozoic Era, 65 million years ago. It is theorized that a large asteroid hit the Earth off the coast of Mexico. This impact caused huge environmental changes that the dinosaurs (and many other species) couldn't adapt to, and they died out - this event was called the K-T mass extinction.

For more details about this and other extinction theories, click on "Extinction" in the margin to your left.

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Q: How many dinosaurs are there?
from Aaron and Chris, Buffalo Grove, illinois, USA; May 22, 1998

A: There are about 330 different known dinosaurs and more are being found all the time.

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Q: My friend is doing a dinosaur report like me,but she need some information. Her dinosaur is the Apatosaurus and she needs to know what is its ancestor (or ancestors).
from Joy S., Cerritos, CA, USA; May 21, 1998

A: Apatosaurus was a diplodocid dinosaur, a Jurassic sauropod. The late Triassic and early Jurassic prosauropods (especially the melanosaurids as they were large herbivores with long necks) may have been the ancestors of the sauropods, but this is not known with any certainty. The melanosaurid prosauropods included Melanorosaurus, Riojasaurus, Blikanasaurus, etc. These prosauropods were the first quadrupedal dinosaurs that were adapted for browsing on tall vegetation.

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Q: when was the high point of the dinosaurs?
from Kyle R., Vancouver, WA, USA; May 21, 1998

A: The dinosaurs were most diverse and abundant during the Cretaceous period, 146-65 million years ago.

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Q: When were dinos. discovered.
from kelli and nikki, Jenkins, KY, USA; May 20, 1998

A: The first dinosaur fossils were found by in England by Gideon Mantell, William Buckland, and others, in the early 1800's. The term dinosaur (meaning "fearfully great lizard") wasn't coined until 1842, when Richard Owen classified the fossils as saurians. Three of these early finds were Iguanodon, Megalosaurus, and Hylaeosaurus.

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Q: Where did the Lambeosaurus live?
from ???, WA, USA; May 19, 1998

A: Lambeosaurus fossils have been found in Montana, Baja California (USA) and Alberta (Canada). Lambeosaurus was a herding dinosaur that may have migrated from shorelines to higher ground to reproduce. For more information on Lambeosaurus, click here.

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Q: What is the defense for Apatosaurus and Brachiosaurus dinosaur?
from Meredith, Waldorf, MD, USA; May 19, 1998

A: The large sauropods' (like Apatosaurus and Brachiosaurus) best defense was their size. In addition, their tails could whip away some attackers. Also, they had leathery skin, although this wasn't much of a defense against sharp theropod teeth. They also had some claws on their feet that were more pronounced in the young. For more information on Apatosaurus, click here. For more information on Brachiosaurus, click here.

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Q: HOW MANY SORTS OF DINOSAURS WERE THERE?
from KATELYN, Rapid, SD, USA; May 19, 1998

A: There are about 330 different known dinosaurs and more are being found all the time.

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Q: Why is Brachiosaurus called "Arm Lizard"?
from Miranda A., Stoneham, MA, USA; May 18, 1998

A: It is called the "Arm lizard" because it's front legs (arms) are longer than its rear legs. This is very unusual among dinosaurs; the Brachiosaurids (which includes Brachiosaurus, Astrodon, Dinodocus, and others) are the only group of dinosaurs built like this. For more information on Brachiosaurus, click here.

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Q: I am doing a report on the Allosaurus, How much did it weigh?How did it take care of its young?
from Glenn R., New Berlin, WI, USA; May 17, 1998

A: I don't have any good references to Allosaurus' weight. Although Allosaurus was the most abundant predator in late Jurassic North America and may have hunted in packs, I haven't seen evidence that they cared for their young (like fossilized nests). For more information on Allosaurus, click here.

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Q: When did the great lakes form as ice sheets in North America retreat.
from Murdock; May 17, 1998

A: They formed during the latest ice ages when ice sheets covered most of North America, scraping the northern parts of the continent. They later retreated, leaving lasting landmarks such as the Great Lakes. The ice ages occurred during the Pleistocene epoch, about 20,000 years ago.

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Q: I am a student at Columbia College in Chicago doing a paper on dinosaurs classification such as their Kindom, Phylum, Class, Order, Family, Genus, and species but I cannot find any info about them. I need to learn about the T-Rex, Brontosaurus, and Stegosaurus. If you can tell me these, I would greatly appreciate it. Thank you.
from Jaimie, Chicago, IL, USA; May 17, 1998

A: The information you want is in Zoom Dinosaurs. Just click on "Classification" in the left-hand margin, and then on "What are Taxonomy and Cladistics." Stegosaurus stenops is one of the examples given (although "armatus" is the type species of Stegosaurus). The Genus and species of T. rex are Tyrannosaurus (Genus) and rex (species). Brontosaurus is an obsolete name; it has been replaced by Apatosaurus (Genus). The type species of Apatosaurus is "ajax", but there are many other species, including "excelsus", which was the type species for the obsolete Brontosaurus.

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Q: What kind of climate did T-Rex live in? What type of land did T-Rex live on?
from ???; May 17, 1998

A: T. rex lived during the late Cretaceous period, a time of great geological and climate changes. There was a lot of volcanic activity, increased continental drift changed the face of the Earth (the supercontinent Pangaea was breaking up), global cooling and the formation of polar ice and increased seasonal extremes, and finally, a catastrophic asteroid that hit the Earth at the end of the Cretaceous, causing extreme climactic changes (cooling, acid rain, atmospheric gas changes, etc.) and a mass extinction. For more information on the Cretaceous period, click here. For more information on T. rex click here.

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Q: Where did T-Rex live in and when? When did the T-Rex become extinct?
from ???; May 16, 1998

A: T. rex fossils have been found in what is now the USA (in Montana, Texas, Utah, and Wyoming), Canada (Alberta and Saskatchewan), and east Asia (Mongolia). T. rex went extinct 65 million years ago in the huge K-T mass extinction. For more information on T. rex, click here.

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Q: How many kinds of Dinosaurs are there?
from Chelsey S., Davidsville, PA, USA; May 16, 1998

A: There are about 330 different known dinosaurs and more are being found all the time.

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Q: Is the Dimetrodon a dinosaur?
from Jared A. W., Fair Oaks, CA, USA; May 16, 1998

A: No, it was another type of extinct animal (a pelycosaur) from the time of the dinosaurs. For an information sheet on Dimetrodon, click here.

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Q: Why don't we have anymore animals of the same size of the dinosaurs??
from Dalton, Orlando, FL, USA; May 16, 1998

A: This is a really great question! Unfortunately, it's also one that no one knows the answer to. Although there are water-dwelling animals that are even bigger than any of the dinosaurs (blue whales), there are no modern-day land animals that are even near the size of the enornous sauropods of the Jurassic period. The size of land animal seems to have peaked during the Jurassic period, reaching lengths over 100 feet long (30 m) and weights perhaps up to 100 tons.

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Q: This might be a little childish using this when i'm in high school (freshman), but hell this site has what i need. Now i'm doing this report in sience on fact of some different dinosaurs, and i'm wondering if it is pagerism if i copy n paste like a paragraph out of the dinosarus info sheet (i just mean a paragraph not the whole info sheet)? if it isn't would u care if i did?
from Matt, boothwyn, PA, USA; May 15, 1998

A: Yes, it is plagiarism to copy any text verbatim (word for word), even a sentence. You shouldn't do it; have some confidence in your own writing ability.

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Q: Hi, My son is doing a report about the Anatosaurus. We were wondering if there is any information on weather it lived in a group or alone? And if there is any information on nesting habits? Did it take care of its babies? Please e-mail me back as soon as you can if you can find any of
from ??; May 15, 1998

A: Anatosaurus is an obsolete name for Edmontosaurus, a duck-billed dinosaur (a hadrosaur). For more information on Edmontosaurus, click here.

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Q: What was the first meat eating dinosaur?
from Ms. Beaudry, Chicopee, MA, USA; May 15, 1998

A: Eoraptor is the earliest known dinosaur and a carnivore (a meat eater). It lived about 230 million years ago. For an information sheet on Eoraptor, click here.

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Q: I need lots of information on the Fabrosaurus. It is extremely hard to get info and pictures on it. Please post if possible. Thank you!
from Joyce C., Cerritos, CA, USA; May 15, 1998

A: Fabrosaurus was an early dinosaur, a primitive ornithischian (a plant eater), 3 feet (1 m) long, long-legged, and lightly built. It had short arms with five-fingered hands, and a long tail. It lived during the late triassic and early Jurassic, about 208-194 million years ago. Fossils have been found in Lesotho, South Africa. It was named in 1964 by Leonard Ginsburg. It is very similar to (and may be the same as) Lesothosaurus.

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Q: What is the Kentrosaurus's ancestors? Why do people think the Kentrosaurus is extinct?
from Joy S., Cerritos, CA, USA; May 15, 1998

A: Kentrosaurus was a stegosaurid, a Thyreophoran, and an Ornithischian dinosaur. The earliest Thyreophoran was Scutellosaurus.

Kentrosaurus was a plated and spiked plant-eater that was about 17 feet long (5 m) and weighed about 2 tons. If there were any of them still around, we couldn't miss them! For more information on Kentrosaurus, click here.

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Q: How big is a T. rex?
from Jaime M. P., Bluefield, West Virginia, USA; May 15, 1998

A: Tyrannosaurus rex was about 20 feet (6.2 m) tall (from head to foot) and over 40 feet (12.4 m) long (from snout to tip of tail). For more information on Tyrannosaurus rex, click here.

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Q: Which dinosaur is the longest, supersaurus or seismosaurus. I have seen sites that say seismosaurus at 150 feet is the longest.
from W. E., Palm Harbor, FL, USA; May 14, 1998

A: For many dinosaur species, only incomplete fossils have been found, sometimes just a few bones or teeth. This is true for both Supersaurus and Seismosaurus. In cases like these, guessing about the animal's physiology is the only way to determine a length statistic. There's a lot of room for disagreement between paleontologists here. I have references that estimate Seismosaurus' length ranging from 108-170 feet (33-52 m) long and Supersaurus' length ranging from 80-138 feet (24-42 m) long. Also, there is some disagreement as to whether or not Seismosaurus is a distinct species; some paleontologists think it may be a large example of Diplodocus.

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Q: what did the Cretaceous period look like? aka vegetation,life,terrain.
from Josh B., Calgary, Alberta, Canada; May 14, 1998

A: The Cretaceous period, 146-65 million years ago, was a time of great geological changes. There was a lot of volcanic activity, continental drift that changed the face of the Earth (the breakup of the supercontinent Pangaea), climate changes, and finally, a catastrophic asteroid hit at the end of the period. During the Cretaceous, flowering plants appeared as did placental mammals. Vegetation included ferns, gingkos, magnolias, cycads, palms, conifers, etc. For more information on the Cretaceous period, click here.

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Q: if dinosaurs are reptiles and peterodactyls are flying repiles why aren't pterodactyls considered dinosaurs?
from Jerry B., West Seneca, NY, USA; May 14, 1998

A: For the same reason that although cats are mammals and dogs are mammals, dogs are not considered to be cats.

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Q: how old could brontosaurus get?
from Heather B., West Seneca, NY, USA; May 14, 1998

A: Brontosaurus (now known as Apatosaurus) has been estimated to have lived to be about 100 years old.

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Q: My son is in the second grade and is doing a report on dinosaurs. He has chosen to report on raptors but i'm not sure that this is the correct name for them. Could you give me the proper name for the tiny dinosaurs.
from dbsnowball, s.orleans, MA, USA; May 13, 1998

A: The dromaeosaurids are sometimes referred to as the "raptors." These dinosaurs were intelligent, small, large-eyed, fast, bipedal, efficient killers that were closely related to birds. They had large, sickle-shaped claws on the middle toe of each foot, capable of slashing prey. They may have hunted in packs, killing even large sauropods. Dromaeosaurus, Deinonychus, Adasaurus, Utahraptor, Elopteryx, and Velociraptor are examples of dromaeosaurids. They were the most intelligent group of dinosaurs. For more information on the dromaeosaurids, click here.

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Q: What was the most litte dinosaur?
from Exequiel V., Santiago, Santiago, Chile; May 13, 1998

A: Compsognathus is the smallest dinosaur yet found.

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Q: How long was each dinosaur period?
from Heather B., West Seneca, NY, USA; May 13, 1998

A: The dinosaurs lived during the Mesozoic Era which lasted from 248 to 65 million years ago. The Mesozoic is divided into 3 periods: the Triassic period (248-208 million yeas ago), the Jurassic period (207-146 million yeas ago), and the Cretaceous period (146-65 million yeas ago).

For more information on the Mezozoic Era and its subdivisions, click here. For more information on geologic time, click here.

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Q: What was the heaviest dinosaur?
from Jay M., West Seneca, NY, USA; May 13, 1998

A: Weight estimates of the dinosaurs are very difficult to determine. The estimates can vary a lot from scientist to scientist, unlike length estimates which are simple to determine and therefore much more consistent.

The enormous Jurassic sauropods were the heaviest dinosaurs, and the most massive of them included Seismosaurus, Brachiosaurus, and Ultrasauros. These dinosaurs may have weighed over 80 tons.

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Q: What are the dimensions of the biggest dinosaur footprint?
from Chris, Austin, TX, USA; May 12, 1998

A: The huge Jurassic sauropods left the largest footprints, over 3 feet (1 m) long, and almost as deep. A set of these tracks are on display at the American Museum in New York. Many sets of fossilized sauropod footprints have been found around the world.

When fossil footprints are found, it isn't always known which species left it, but it is usually possible to deterimine what general type of dinosaur made the track, since different types of dinosaurs had different foot structure, (like number of toes and claws, length of toes and claws), toe or heel walking, stance (bipedal vs. quadrupedal), length of stride, etc. Considering the huge size of sauropods and their feet, there is little doubt that when enormous footprints are found, they were from sauropods.

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Q: What were the Tyrannosaurus's enemies?
from Teddy C., Lake Worth, Florida, USA; May 12, 1998

A: Tyrannosaurus rex was at the top of the food chain when it lived, during the late Cretaceous period. Only the very young, injured and diseased T. rex's were vulnerable to attack from other large predators or groups of smaller predators. For more information on Tyrannosaurus rex, click here.

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Q: What Was The Weather Like When The dinosaurs existed?
from St Joseph's High, Albion Park, N.S.W., Australia; May 11, 1998

A: The dinosaurs lived during the Mesozoic Era, 248 to 65 million years ago, a time when the Earth's climate and geography were very different than they are now. For most of the Mesozoic, the Earth's continents were jammed together into the supercontinent Pangaea. The climate was mostly warmer than it is now, with some periods being much warmer, with very little seasonality (that is, very little difference between winter and summer extremes), little or no polar ice, and higher sea levels. See the chart below for a little more detail. For even more details, click on Mesozoic in the margin to your left and see the sections on the periods of the Mesozoic, the Triassic, the Jurassic, and the Cretaceous.

The Age of Reptiles	The Mesozoic Era 248 - 65 million years ago
	Triassic Period 248 - 208 million years ago	Jurassic Period 208-146 million years ago	Cretaceous Period 146-65 million years ago
Continental Drift	One supercontinent, Pangaea.	In mid-Jurassic, Pangaea began to break apart, into Laurasia and Gondwana.	Continental drift continued at a fast pace, with accompanying volcanic activity. The continents almost had their modern-day look.
Climate	Hot and dry, with strong seasonality.	Hot and dry, with strong seasonality at first, changing to warm and moist with no polar ice and vast flooded areas.	Temperatures were warm, seasonality was low, and global sea levels were high (no polar ice!) at the beginning of the Cretaceous. Later, sea levels dropped, seasonality increased, and there were greater extremes in temperature between the poles and the equator.
Plants and Animals	Small, fast dinosaurs appeared for the first time. The first tiny nocturnal mammals developed. Ichthyosaurs (marine reptiles) swam in the seas. Ferns , cycads , and early gymnosperms (conifers) abound.	More dinosaurs, including gigantic ones, roamed the earth, and pterosaurs flew. Archaeopteryx, the first primitive dinosaur-like bird developed.	Dinosaurs flourished, flowering plants (angiosperms) appeared, displacing conifers and others. A major extinction occurred at the end of the Mesozoic, 65 million years ago.

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Q: I was looking for some information on the Dilophosaurus. But I can barely find a page of info if you have some please send it to me.
from Ben S., Chesapeake, Virginia, USA; May 11, 1998

A: For an information sheet on Dilophosaurus, click here.

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Q: I am trying to printout your question/answer pages but they do not print out well, words are over lapped and thus cannot be read. Does anyone else have this problem? I like your site very much and would like to use some of the information therein. Regards,
from Walter E., Palm Harbor, FL, USA; May 11, 1998

A: The problem with the printing might be that Zoom Dinosaurs is composed of many "frames", including the left-hand margin and the large content frame on the right. To print just the large content frame, click on that part of the screen to select that frame, then choose "Print frame..." on the FILE menu. That ought to work. It it doesn't work, please write again, and we'll figure it out.

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Q: Need size, picture, diet and time period for Trachodon....HELP!!!!
from Chris, NYC, NY, USA; May 10, 1998

A: Trachodon (meaning "rough tooth") is a plant-eating dinosaur that is known only from a few teeth found in Montana, USA! It dates from the late Cretaceous period, about 77-73 million years ago. From the teeth, it has been surmised that it was probably a duck-billed dinosaur. It was named in 1856 by Joseph Leidy. There's an interesting page on Trachodon at Dinosauria.com.

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Q: Could you send me a size comparison chart of a Triceratops along with some of the names and information of some plants and other dinosaurs that shared the same time frame with the triceratops as soon as you can because my report is due on May 13,1998.
Thank You,
Nichole
from Nichole L., Loxahatchee, FL, USA; May 10, 1998

A: Click here for my information sheet on Triceratops that will answer your questions.

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Q: How long did the average dinosaur live?
from Carleigh, Kittery, Maine, USA; May 10, 1998

A: I don't know. It has been estimated that the huge sauropods, like Apatosaurus, Brachiosaurus, Diplodocus, and Supersaurus lived to be about 100 years old. Smaller dinosaurs may have lived shorter life spans.

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Q: How many dinosurs were there ?
from Jesse, West Seneca, NY, USA; May 8, 1998

A: About 330 different dinosaurs have been discovered. More are being found all the time.

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Q: HOW MUCH DID THE TRICERATOPS WEIGH?
from TEBE, Baltimore, MD, USA; May 8, 1998

A: Triceratops weighed about 6-12 tons. Weight estimates of the dinosaurs are very difficult to determine. The estimates can vary from scientist to scientist, unlike length estimates which are simple to determine and therefore much more consistent. Click here for an information sheet on Triceratops.

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Q: How many plates does a stegosaurus have?
from Tyler, West Seneca, NY, USA; May 8, 1998

A: Stegosaurus had two rows of thin, triangular plates running along its back. Different specimens have different numbers of plates; I've counted 13-19 on different fossils. Neither the exact positioning of the plates nor their function is known. Also, different species of Stegosaurus had different numbers of tail spikes; Stegosaurus ungulatis had 8 spikes and Stegosaurus stenops had 4 spikes. For more informtion on Stegosaurus, click here.

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Q: What was the first dinosaur that lived?
from Nicole, West Seneca, NY, USA; May 8, 1998

A: Eoraptor is the earliest known dinosaur. It lived about 230 million years ago. For an information sheet on Eoraptor, click here.

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Q: What was the tallest dinosaur?
from Jennifer, West Seneca, NY, USA; May 8, 1998

A: The tallest dinosaurs were brachiosaurid sauropods; they had front legs that were longer than their back legs and had a giraffe-like stance. They were gigantic, slow moving, tiny-headed, cow-like plant-eaters from the late Jurassic and the Cretaceous period. They had very long necks which were held upright and were useful for reaching wide (and tall) swatches of vegetation. The lengthy neck was counterbalanced by a massive tail. These sauropods included Brachiosaurus, Ultrasauros, and Supersaurus.

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Q: What is the fastest Dinosaur?
from Eddie, West Seneca, NY, USA; May 8, 1998

A: The fastest dinosaurs probably weren't any faster than modern-day land animals. The speediest dinosaurs were bird-like bipedal carnivores (theropods) with long, slim hind-limbs and light bodies (hollow bones and a streamlined body):

Dromiceiomimus (meaning "emu mimic"), an ornithomimid, had long legs, a small head, a toothless beak, weighed about 220 pounds (100 kg), and was 11.5 feet (3.5 m) long). Ornithomimus (means "bird mimic") -was an ostrich-like oviraptor with a toothless beak, long legs, and hollow bones. Could probably run as fast as an ostrich, , which can run up to 43 mph (70 kph). Coelophysis (means "hollow form") - from the late Triassic period, had very sharp, serrated teeth and hunted in packs. Velociraptor (means "speedy thief") - from the Cretaceous period, had very sharp teeth and retractable claws on its feet .

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Q: What was the name and length of the longest known dinosaur?
from M.A. Graziano, West Seneca, NY, USA; May 8, 1998

A: Supersaurus, which was about 134 feet long (41 m), may have been the longest dinosaur. For an information sheet on Supersaurus, click here.

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Q: How tall was T-Rex?
from Thomas Y., West Seneca, NY, USA; May 7, 1998

A: Tyrannosaurus rex was about 20 feet (6.2 m) tall (from head to foot) and over 40 feet (12.4 m) long (from snout to tip of tail).

For more information on Tyrannosaurus rex, click here.

A dinosaur's length (from snout to tail) is usually the primary measurement given beacause it is the easiest and most accurate statistic to determine - you just need a fossil skeleton and a tape measure. Other statistics, like height require some assumption to be made about the dinosaur's stance. Most dinosaurs heights are the measured from the ground to their hips. To calculate a dinosaur's height up to its head, you first must determine exactly how it stood - did it hold it's head up high, or part-way up, or maybe down? Until recent decades, paleontologists thought that most dinosaurs had very different stances than they do now.

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Q: what is your name?
from Tiffany C., NY, USA; May 7, 1998

A: Jeananda Col

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Q: What is an Ornitholestes? Where can I find information on the web for this dinosaur? My daughter has a project due and this is the name the teacher gave her. Need ASAP
from ?; May 6, 1998

A: Ornitholestes (meaning "bird robber") was a carnivore from the late Jurassic period, about 156-145 million years ago. It walked on two long legs, was lightly built, and must have been a very fast runner. It had a small head, a small bony crest on its long snout, a long, tapered tail, and strong, clawed, four-fingered hands (one finger of which was tiny). It was about 6.5 feet (2 m) long (from snout to tail). It may have hunted the newly evolved Jurassic period birds. Fossils have been found in Wyoming, USA. Ornitholestes was first described by the US paleontologist Henry F. Osborn in1903.

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Q: What made dinosaurs extinct?
from Brandon A., Bluefield, West Virginia, USA; May 6, 1998

A: Most dinosaurs went extinct because they couldn't compete with other species - these extinctions are called background extinctions. For those remaining dinosaurs, extinction came at the end of the Mesozoic Era, 65 million years ago. It is theorized that a large asteroid hit the Earth off the coast of Mexico. This impact caused huge environmental changes that the dinosaurs (and many other species) couldn't adapt to, and they died out - this event was called the K-T mass extinction.

For more details about this and other extinction theories, click on "Extinction" in the margin to your left.

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Q: i am doing a report on dinosaurs with another partner and i was wondering if i could have a volunteer scientist (paleontologist) come to my school and be a guest speaker (i need extra credit) and it would do me a great thanks if someone could come May 27 (Wednsday) 1998 at around 1:45 p.m. at Villa Park High School address: 18042 Taft Ave. Villa Park CA. 92861. This would do me a great favor. Thanks
from Brittany Z., Villa Park, CA, USA; May 5, 1998

A: I would if I could, but I live in Washington State.

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Q: I'm doing a report on the Hylaeosaurus and information is proving to be very scarce. If you could post some info on this dino, I wouild be very grateful
from Kim, Stillwater, Minnesota, USA; May 5, 1998

A: Hylaeosaurus (meaning "woodland lizard") was an armored, quadrupedal, plant-eating dinosaur from the early Cretaceous period, about 135-119 million years ago. It was about 13 feet (4 m) long, had short legs, spikes along its shoulders and sides, and oval plates all over the top of its body. It had a toothless beak and leaf-shaped cheek teeth. It ate low-lying plants. It was an ankylosaur and a nodosaur (with no tail club). Its fossils have been found in southeast England. Hylaeosaurus was named in 1833 by the British paleontologist Gideon A. Mantell. For more information on Hylaeosaurus, click here.

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Q: What are some of the special features of the Velociraptor?
from Daniel, Rosthern, ?; May 5, 1998

A: For information on Velociraptor, click here.

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Q: I'm doing a report on the Troodon. Can you send me some information on it. Thanks.
from Benny C., Mahtomedi, MN, USA; May 5, 1998

A: Troodon (meaning "wounding tooth") was a human-sized, fast, long-legged bipedal (walked on two legs) meat eater with serrated teeth and long, slim jaws. Troodon lived during the late Cretaceous period, about 76 to 70 million years ago. It may have been the smartest dinosaur, having the largest brain in proportion to its body weight (as smart as a modern bird). It was a theropod about 6 feet (1.75 m) long with a stiff tail. Troodon had large eyes and perhaps had a good sense of hearning. It had a large, sickle-shaped toe claw on its second toe, and smaller ones on the other. It had three long, clawed fingers. Its fossils have been found in Montana and Wyoming, USA, and Alberta, Canada. Troodon belonged to the family Troodontid. Troodon was discovered by Ferdinand V. Hayden in 1855. Troodon was named in 1856 by Joseph Leidy.

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Q: How tall was the tallest dinosaur? How small was the smallest dinosaur?
from rodney and jackelin, boston, ma, USA; May 5, 1998

A: The tallest dinosaurs were Ultrasauros, Supersaurus, and Brachiosaurus. The smallest, Compsognathus, was about 2 feet (60 cm) long, the size of a chicken. For more extreme dinosaurs, click here.

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Q: "What kind of plants did Stegosaurus eat? How much do we know about what Stegosaurus ate?"
from Nyree L., Brisbane, Queensland, Australia; May 5, 1998

A: I don't have any references that tell exactly which Jurassic plants that Stegosaurus ate. Common plants during the Jurassic were cycads, ferns, horse-tails, conifers, palms, and some broad-leafed trees (like gingkos and magnolias).

There are many different ways to study dinosaurs' diets, including looking at:

• Fossilized feces - Coprolites help identify dinosaurs' feeding habits.
• Fossilized stomach contents - these are very rare to find.
• Teeth - A dinosaur's tooth structure also tells us what type of food the dinosaur ate. Meat eaters need sharp teeth for for tearing flesh; plant eaters have teeth that would strip, and perhaps chew, foliage.
• Gastroliths - Gizzard stones (which aided digestion), have been found with some dinosaur fossils. These also yield information about dinosaur diets.
• Girth - Gut size is also an indicator of diet. Large plant eaters need a lot of calories to sustain their mass. In order to get sufficient energy from plant matter, a lot of vegetation must be digested. This requires a large digestion area.

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Q: I don't have any question but I do have a request, can you please send me some pic of the dinosaur Maiasaura. I need a lot 4 a project. Please send B 4 5-5-98. Thanks U R a life saver!!!
D.J. :)
THANKS
from D. J. J., Stafford, TX, USA; May 5, 1998

A: At the moment, all my dinosaur information is on-line. For information and a picture of Maiasaura, click here.

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Q: Did Gigantosaurus have bigger teeth than Tyrannosaurus rex.
from Brittany, age 5, Dover, NH, USA; May 5, 1998

A: Tyrannosaurus rex and Giganotosaurus had very different types of teeth. Tyrannosaurus rex's teeth were cone-shaped, slightly curved, and the longest were about 6 inches (15 cm) long. Giganotosaurus' longest teeth were a little longer, about 8 inches (20 cm) long, and were serrated (they had jagged edges).

For more information of these dinosaurs, click here for Tyrannosaurus rex or here for Giganotosaurus

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Q: I do not have a question but I do have a comment. I think that program is the best that I have ever Played. Could you send me some information or stuff that you have??
Thanks a lot for making this. I makes my day bright!!!!!!
Love Alyssa W. Cance
from Alyssa C., Chapel Hill, NC, USA; May 4, 1998

A: Thank you!!! At the moment, all my dinosaur information is on-line.

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Q: how deadly was the Utahraptor?
from ??; May 4, 1998

A: Utahraptor was a very deadly predator; it was a speedy, bird-like predators armed with huge claws, sharp teeth, and wing-like arms that gave it more stability and mobility during a chase. For an information sheet on Utahraptor, click here.

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Q: Do you have information on the "Stygimoloch" or river styx devil dinosaur for a school report I am doing at Oak Grove School in Green Oaks, Illinois? Thank-you, Thank-you, Thank-you.
from Makara F., Lake Bluff, Illinois, USA; May 2, 1998

A: Stygimoloch (meaning "demon from the river Styx") was a bipedal, plant-eating dinosaur with very strange, demonic-looking spikes and bumps on its skull. The many horns ranged up to 4 inches (100 mm) long. Stygimoloch was about 7 feet (2 m) long) and lived during the very late Cretaceous period, about 68-65 million years ago. Only parts of Stygimoloch's skull have been found - in Montana, USA. Stygimoloch belongs to to the family Pachycephalosauridae, the Ornithischian dinosaurs that had domed, spiked skulls. Pachycephalosaurs probably engaged in head-butting both as a defense and in intra-species rivalry. Stygimoloch was named in 1983 by British paleontologist Peter M. Galton and German paleontologist Hans-Dieter Sues.

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Q: am trying to find information on the Trachodon. Does it have another name? Can you recommend a website? Ronnie
from Ronnie K., Bliss, NY, USA; May 1, 1998

A: Trachodon (meaning "rough tooth") is a plant-eating dinosaur that is known only from a few teeth found in Montana, USA! It dates from the late Cretaceous period, about 77-73 million years ago. From the teeth, it has been surmised that it was probably a duck-billed dinosaur. It was named in 1856 by Joseph Leidy. There's an interesting page on Trachodon at Dinosauria.com.

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