T-Rex a Predator or a scavenger? When is T-Rex Era(Time)?
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T. rex (Tyrannosaurus rex) was a large, meat-eating therapod dinosaur that lived during the late Cretaceous period of the Mesozoic era (about 70 to 65 million years ago).\n\nThere is no question that it ate meat, with huge steak-knife like teeth, binocular vision and other adaptations, but paleontologists have argued over whether or not it was a scavenger or active predator.\n\nMany of the proponents of each theory seem to forget that very very few animals are completely either/or.\n\nIn modern times, hyenas are considered scavengers while lions are generally considered top predators.  However, hyenas quite often kill their own prey, coopertating to take down wildebeest or zebras by themselves.  And lions often chase the hyenas off their kills, and scavenge the meal themselves.\n\nSo T. rex could indeed have been an active predator, hunting down or ambushing prey, but also could have been a scavenger, tracking down dead dinosaurs with its keen sense of smell, and it would have been well equipped to drive off almost any other predator that was already at the kill.  Even something as formiddable as a pack of Deinonychus probably would have backed off when T. rex came charging over the hill.\n\nThe fact that T. rex shows adaptations that could have been useful for either lifestyle says to me that they were probably flexible.  They may have acted primarily as scavengers in an area where other predators were common, but would have been able to become the dominant predator in other regions.  \n\nAnimals tend to be more complex than simply either/or statement.  Especially large, adaptable animals.  I think it's likely that T. rex was a predator in some regions, under some circumstances, and in other regions, with different circumstances it was primarily a scavenger.  Even the same animal may have changed its habits over the course of the year as it moved to different regions.
542499
They still are.\n\nStegosaurus, tyranosaurus, etc. is still the correct name for a specific animal (like tyranosaurus rex), stegosaur or tyranosaur is the correct name for referring to any animals in that particular genus.
175862
Sadly, there are no dinosaurs left living today.  All evidence indicates that they completely died out 65 million years ago, at the end of the Cretaceous period.\n\nThere is some evidence to indicate that birds are descended from one branch of the dinosaurs (not everyone agrees on this), and so in some sense it could be said that dinosaurs are not truly extinct, but that's like saying that since we're still around the Australopithecines are not extinct.  \n\nThe animals that bear the characteristic features that lead them to be classified as dinosaurs are indeed extinct.\n\nCrocodiles and alligators are somewhat related to the ancestors of the dinosaurs, but are not and never were dinosaurs themselves.  They share some of the features of the dinosaurs (teeth set in socketed roots in the jaw etc.), and are the most 'advanced' reptiles alive today, but they are not dinosaurs.\n\nThere are some who claim that creatures such as the Loch Ness Monster ('Nessie') are Plesiosaurs that somehow managed to survive for millions of years, but there is very little evidence to suggest that Nessie actually exists, and even if she did, Plesiosaurs were not Dinosaurs.  They're Plesiosaurs, a totally different lineage with considerably divergent skull morphology from the Dinosaurs.\n\nThere is a creature rumoured to exist deep in the jungles of the Congo, known as Mkele Mbembe.  Descriptions of Mkele Mbembe sound as though they might (might) be describing a small sauropod Dinosaur of some kind.  If Mkele Mbembe exists (doubtful), and it turns out that it is indeed a living Dinosaur (also doubtful) then we would have a living Dinosaur still on the planet, and we'd have to try and figure out why no Dinosaur fossils have shown up anywhere on Earth in that 65 million year span.
923345
Crocadiles...\n\nSupposing that an impact was the cause of the dinosaur's demise, it would not have been an imediate death.  \n\nAn impact would have thrown dirt into the upper reaches of the atmosphere.  The Sky would have been dark day gray for a long time, and the Earth would have grown cold for years...\n\nThose animals that needed the most food would have died first, and in that order of sucession until the only survivors would have been the small scavengers.  The dinosaurs that could feed on the starved carcasses of the dead.\n\nAnd so the decendents of those survivors have had to continue to evolve to survive this colder and crueller Earth.  \n\nThe would have needed to develop an insulating layer...  Some will tell you the Birds evolved from those survivors, and if they are right then those feathers are a post-Impact survival trait...\n\nThe question has to be if there was an intelligent races of Dinosaurs...  I mean, if we suffered an equally destructive impact today, we wouldn't have the forewarning to see it coming even now...  How much of humanity would survive?  Forty Years of darkness and artic cold...
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That guy is lying!  The meteroids took out the dinosaurs.  The ice age was much later.  Meteriods slammed into the Earth, kicked up a huge amount of dust into the sky.  From there, the sun couldn't get through the dust in the atmosphere.  Lack of sunlight killed all the plants and did make it a lil colder.  Plant eating dinos died first.  Then the carnivore dinos lost animals to hunt and kill because they weren't there to eat.  No food supply led to a slow death of them and most other animals on the planent at that time
1064624
Good point!\nAs for them being veggi beforehand...LMAO! (I wonder what that fossilized *meat* was, found in a dino's stomach? T-Rex, anyone?)\nIt's not just animals either, it goes right down to the microscopic level. I could point out the fact(scary word for xtians!)that there's more prey than predators too...but I won't. \nNature is cruel to be kind.\n\n:)
892655
Dinosaurs did evolve, that is why they were so successful for such a long period of time. However, it is very difficult for species to recover from catastrophic population declines. Remember also that the major extinction event that occured 65 mya was not actually the only mass extinction event that took place during the time of dinosaurs and mammal-like reptiles and that this extinction event wasnt actually as catastrophic as some of the others (the P-T event wiped out 95% of all life!). What instead took place was that small mammals held a niche which evolved into the many mammalian species we have today. \nIf you follow the geological time line from the tertiary period to late cretacious you will actually notice evolution occuring throughout dinosaur species. Dinosaurs diverged from large lumbering archosaurs into saurapods and therapods and adapted to a range of environments. And, of course, therapod characteristics are evident in modern day birds (this is still debated, not proven, though very strong evidence in support). \nI would highly doubt that humans, without technological advancements, medicine etc etc would be able to survive for as long as the dinosaurs did, or to withstand as many mass extinction events. Look back as far as the cambrian explosion and you'll see that all life has come a long way!
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For the population density of say, a large sauropod, which were chiefly herbivorous, they would have had to consume extreme amounts of high energy foods to grow fast.  Since plants require a massive metabolism to digest, their metabolism must have been very slow, which in turn means that they grew slowly.  \n\nA carnivore like your garden variety t-rex, which was also very large, would have had a faster metabolism because he ate (supposedly) large quantities of protein, but still, every organism´s metabolism is dictated by the same rules, so t-rexes must have been slow too, thus indicating that they also grew up pretty slow (considering their size of course).
420087
YES man was made on the same day as dinosaurs! and he walked with them for a long time.\n\nwell thankyou for calling me a complete idiot gratvol, but i know that you are sadly mistaken.
709203
Evolutionary left over when The T-rex's ancestor needed arms.  They shrank because they didn't need them anymore.
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Adapted from Dinosaurs: The Very Latest Information and Hands-On Activities From the Museum of the Rockies, by Liza Charlesworth and Bonnie Sachatello-Sawyer. A Scholastic Professional Book.\n\nWay back in 1676, Robert Plot, the curator of an English museum, described and drew a thigh bone that he believed belonged to a giant man. Although that fossil disappeared without a trace, the surviving illustration suggests that it may well have been part of a "Megalosaurus." Later, in 1822, large teeth discovered in England by Mary Ann Mantell and her husband, Gideon, were thought to be the remains of a huge and extinct iguana. It wasn't until 1841 that British scientist Richard Owen came to realize that such fossils were distinct from the teeth or bones of any living creature. The ancient animals were so different, in fact, that they deserved their own name. So Owen dubbed the group "Dinosauria," which means "terrible lizards."\n\nAcross the ocean in North America, dinosaur tracks were studied in the Connecticut Valley, beginning in the 1830's. They were believed to belong to enormous ravens, freed from Noah's Ark after the Great Flood. At that time, paleontology was long on deduction and short on evidence. This was remedied when two wealthy and competitive American scientists, Othniel Marsh and Edward Cope, raced to excavate fossils in the Rocky Mountain region. In the late 1800's, their separate teams, armed against Native Americans and each other, dug up tons of bones from several sites. All in all, Marsh and Cope's rivalry — known as the Bone Wars — uncovered 136 new species. And their respective fossil displays generated excitement for dinosaurs the world over.\n\nIn the 1900's, enthusiasm for dinosaurs grew steadily, attracting the attention of the scientific community. Institutions such as the Carnegie Museum of Natural History and the American Museum of Natural History assembled dig teams, which uncovered many rich bone beds in North America (as did their counterparts overseas). New sites in Utah revealed several different species, including "Camarasaurus," "Apatosaurus," and "Stegosaurus;" "Tyrannosaurus rex" remains were found in Montana and baby Coelosaurs in New Mexico.\n\nIn recent decades, dinosaur research continues, but the emphasis has shifted from finding and classifying these animals to analyzing and reconstructing their lives and habitats. In the late 1960's, Robert Bakker proposed that these ancient creatures may well have been as agile and energetic as warm-blooded animals. In the mid 1970's, Peter Dodson, along with James Farlow, hypothesized that they used their horns to attract the attention of females, as well as for fighting. And in the late 1970's, Jack Horner made history by identifying some of the first dinosaurs nests and eggs in North America. These important "Maiasaura" fossils helped to determine that some species nested in colonies and cared for their young.\n\nIn the past few years, several paleontologists, including Ken Carpenter, Phil Currie, and William Coombs, have identified juvenile dinosaurs that were previously thought to be adults; and David Weishampel has theorized that some dinosaurs probably used their crests and nasal passages to create sound. Each day, scientists working all over the world, in the field and in research labs, help to redefine the meaning of the world "dinosaur."
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The sudden mass extinction of the non-avian dinosaurs, which occurred around 65 million years ago, is one of the most intriguing mysteries in paleontology. Many other groups of animals also became extinct at this time, including ammonites (nautilus-like mollusks), mosasaurs, plesiosaurs, pterosaurs, herbivorous turtles and crocodiles, most birds, and many groups of mammals.[32] The nature of the event that caused this mass extinction has been extensively studied since the 1970s. At present, several related theories are broadly supported by paleontologists.\n\nThese were some of the causes for their extinction as well:-\n\nAsteroid collision\nMultiple collisions—the Oort cloud\nEnvironment changes\n\nFor more information go through the link below.
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Don't think there's such a thing as a komodo rhino. There's a komodo dragon, but it couldn't kill T Rex. Not right away, but if it bit it and ran away, maybe. Their mouth is highly septic.
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Haven't you ever heard of the Churchosaurus Rex? Big creature with a bible tail, used it to bible thump non-believing dinosaurs. I heard those ankylosaurus were a hard dinosaur to crack. Probably ended up in tar pit hell. \n\nI kid, I kid!
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You have 5 major extincion events in Earth's history:\n\nThe more famous is the K-T Extinction Event aka the day the dinosaurs became oil about 65 million years ago.  That killed the majority of the animals on land, sea and air.  \n\nThe most powerful was the one that occurred 251 million years ago and took 95% of all life on Earth.  Use the link to find about the rest.
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Birds are the direct descendents of dinosaurs.  Many scientists will say they *are* dinosaurs.  As such, they are alive, so dinosaurs are alive.\n\nWhile it remains possible that some dinosaurs proper have survived, it is extremely unlikely at this point.  There is no physical evidence for it.\n\nYour second question is difficult to answer.  Are there prehistoric creatures that have survived?  Sure!  Pretty much every species on earth today (even humans!) is older than history, that makes it prehistoric!  Defining prehistoric any other way would essentially make prehistoric mean "not surviving today", so the answer would be no.\n\nWhat you mean, of course, is creatures to have survived from truly ancient times, such as from the Mesozoic (age of dinosaurs) or older, but again, it's difficult to answer.  There probably aren't any actual species that old, but it's difficult to tell if something in the fossil record is actually the same species as something alive today.  Consider, lions and tigers look and act very different alive and are certainly two different species, but it is very difficult to tell their skeletons apart.\n\nA lot of so-called "living fossils" really aren't.  For instance, we have no fossils of the Coelacanth.  It's closest relatives in the fossil record are in another family (as different as cats and dogs).  Cockroaches are often said to have been unchanged for millions of years, but it's not the case as the fossil record records them evolving continuously.  The first fossil cockroaches had three pairs of wings!\n\nBut some things have survived nearly unchanged for millions of years.  Six-gill and Port Jackson sharks are very much like they were in the age of dinosaurs.  The Tuatara is surprisingly like it's Mesozoic relatives.\n\nBut the king of living fossils is the Lingula brachiopod.  It looks like a clam and lives by filter feeding, but don't let it's calm appearance fool you.  These little guys are survivors.  They've been living in Earth's oceans almost unchanged for 550 million years!  That's almost as long as we have animal fossils at all!  Dinosaurs are hardly teenagers by comparison!\n\nAddenda:  The Komodo Dragon is NOT believed to be a dinosaur, at least not by scientists.  It is just a large monitor lizard.  Dinosaurs are not lizards, being classed among the Archosaurs with the crocodiles, pterosaurs and birds.
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Dinosaurs died 100,000,000 years ago. \nThey're gone! Get over it.