Did mammals hibernate in the cretaceous?
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Perhaps... the weather during the early part of the Cretaceous was warmer than today (and more uniform.)  I'm actually in the process of writing a paper exploring the possibility of hadrosaur hibernation in northern Alaska.\n\nI took a tour of a dinosaur resource center today.  The tour guide said that ability to adapt is what saved KT survivors.  Crocodiles can go months without eating.  Birds migrate.  Fish could swim to deeper water.\n\nIt is still highly debated to what caused the Cretaceous Tertiary extinction.
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the atmosphere was heavily clouded with dust that took a very long time to settle out. This caused a drastic cooling of the surface temperature of the earth. Dinosaurs, being cold blooded, could not survive that drastic a climatologic change. In fact, it is posited that an ice age began as a result of the impact and dust. If you look at major volcanic eruptions over the past few hundred years you can see the same phenomenon occurring with regard to temperatures.
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Reptiles and many other animals, particularly most insects live at the temperature of the world around them - cold when it is cold and hot when it is hot - this is called poikilothermy, or being poikilothermic. Endothermy means generating heat internally. All mammals are endothermic and most are homeothermic. \n\nWe maintain our inner temperature by burning food (oxidation) within ourselves and we stay cool by sweating, panting and changing our postures and place in the world. Sweating and panting work by generating heat loss through evaporating water; changing posture allows us to control to some extent the heat absorbed from the world around us; while changing position simply means seeking shade or shelter when it is too hot. Mammals are unique in possessing hair and in many mammals hair varies throughout the year. these mammals possess a thick insulating coat of hair during winter and a much thinner one during summer.\n\nBeing warm blooded gives mammals a distinct advantage in may habitats, allowing them to be active when reptiles are hardly able to move. It also allows mammals to live in habitats where reptiles cannot live at all, such as the arctic, mountain tops, etc. The reason behind this is that muscle activity is basically dependent on chemical reactions, as are all biological functions. Chemical reactions run slowly when it is cold, but quickly when it is hot. This is because heat is synonymous with (the same as) energy. The more energy you have the faster the chemical reaction occurs. In the early mammals being endothermic probably allowed them to be active at night when competing reptiles were forced to rest or be sluggish.\n\nBeing warm blooded is costly. Mammals and bird have mush greater energy requirements than reptiles of a similar weight.
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MEZOZOIC, CRETACEOUS AND JURASSIC PERIOD (FROM 125 MILLION YEARS AGO TO 65 MILLION YEARS AGO
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Well they dont hibernate or go into torpor like ground squirrels or bears do. They have peiods, sometimes lasting several days with reduced activity, but they will emerge on the warmer days and forage for food. They remain opportunistic during the wionter months as well, if the oportunity for food presents itself, they happily respond!
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for the same reason as llamas pandas and koalas aren't mentioned. The peoples of the Eastern end of the Mediterranean probably travelled no more than a hundred miles from their place of birth in their lifetime and so had no concept of other continents and other flora and fauna, let alone extinct species
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Diet is reconstructed by reconstructing the animal and reconstructing its environment.\n\nReconstructing the environment can be achieved by looking at the plant fossils that occur alongside an animal. That gives a good indication what type of habitat the animal lived in, whether it was tropical rainforest, arctic tundra, desert etc. With that information it is possible to construct a list of possible diets. For example we won’t speculate that an animal could have eaten bamboo if it live din deserts, and we can rule out that an animal ate lizards if it lived in polar wastes.\n\nThe next step is to reconstruct the animal itself. \n\nThat reconstruction normally starts with the teeth. Teeth can tell us a lot about diet. For instance predatory animals usually have sharp widely-spaced teeth like a lion or crocodile, while herbivores have rounded, closely packed teeth like a cow.  \n\nThe next step is to look at teeth wear. Looking at teeth structure gives us a lot of information about diet but it isn’t perfect since animals like pandas and fruit bats have sharp carnivore type teeth yet live entirely on plants. But plant leaves contain a lot of hard material and they wear teeth away very fast and leave a lot of scratches, so we can see whether an animal ate a lot of plant material by looking at the teeth. That way we can tell separate out animals like pandas and fruit bats that recently evolved a vegetarian diet from their carnivorous descendants.\n\nThe next step is to reconstruct the rest of the skeleton. By looking at the ways the bones are hinged and how big the muscle attachment points were we can get a very good idea of how an animal moved. That then tells us thing like whether a meat eating animal was strong and fast enough to make its own kills like an eagle, or whether it had to rely on scavenging like a vulture. It also tells us whether an animal could climb, or swim or burrow.\n\nThe final step is to look at injuries. When bones break they leave a scar even after hey heal, and starvation and disease also leave marks on bones. By looking for those signs we can see whether the animal was suffering from injuries associated with being kicked by prey animals, or from falls from trees and so forth and we can tel whether its prey was seasonally abundant like salmon, or whether it was available year-round like tropical grasses.\n\nSo now we know what types of food existed alongside the animal because we reconstructed its habitat.\nAnd we know what the animal was adapted to eat by the tooth structure.\nAnd we know how much plant material it ate from the wear on the teeth.\nAnd we know whether the animal got that food by hunting, scavenging, swimming, climbing etc. from the muscle and bone structure.\nAnd we know when that food was available, what sort f animals were being attacked by predators and so forth.\n\nWith all that information we can build up a very accurate picture of animal diets just form fossil evidence.
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in the ice age all mammals died not just a few species.the temperature was very cold and mammal were the first to be extinct.just like right now if an ice age came the mammals of the forests would go first along with insects. now there would be a few insect species that would survive but only for a short time. that does not include mammals of the ocean.water especially salt water freezes at a lower temp than plain water
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As a late development of the dinosaurs Archeopteryx would have come extinct at the Cretaceous-tertiary boundary about\n66 million years ago (when all dinasaurs became extinct)the cause was a large asteroid that hit he earth off Yucatan in Mexico causing cataclysmic environmental changes.\n\nhttp://en.wikipedia.org/wiki/Archaeopteryx
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Argentinian Patagonia. Plenty of dinosaurs waiting to be dug out!\n\nhttp://www.argentinaxplora.com/activida/paleo/amesopat.htm\nhttp://www.argentinaxplora.com/activida/paleo/paleotre.htm
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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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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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Jaguars do not hibernate.\n\n"The jaguar's habitat ranges from the rain forests of South and Central America to marshy and even desert terrain in Mexico, but they are rarely seen in mountainous regions. The jaguar's wide range means that it should not be in danger of extinction in the foreseeable future. The species has declined numbers in some areas due to habitat loss, especially in rain forests and grassland turned into cropland and hunting for their pelts.\n\nKnown for their strong swimming abilities, the jaguar is one of the few cats besides tigers that enjoy water. They often prefer to live by rivers, swamps, and in dense forest with thick cover for stalking prey. They are the largest carnivore in the Western Hemisphere. Jaguars, on rare occasions, are seen as far north as the southwestern United States, particularly in Arizona, New Mexico and Texas. In the early 1900s, the jaguars' range actually extended as far north as southern California and western Texas. As recently as 2004, wildlife officials in Arizona have photographed and documented jaguars in the southern parts of the state. Presently it is unclear whether recent sightings indicate whether there is a permanent population developing in the Southwest or that these cats are simply transients straying over the border from Sonora, Mexico. However, jaguars are a protected species in the United States under the Endangered Species Act and are considered nongame, therefor making it illegal to shoot a jaguar for its pelt. Fossils of jaguars from as far north as Missouri confirm these cats inhabited much of the Southern U.S. during prehistoric times. These prehistoric jaguars were signifigantly larger than the jaguars of today."
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Thye lived a long time ago, and the closest living relative to the dinosaurs is the crocodile.  Crocodiles have remained unchanged for 1000's of years.
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Based on the accumulating evidence, mammals, birds, and dinosaurs all evolved from reptiles.  In fact, mammals are way older than birds and were contemporary with the dinosaurs.\n\nThe other evidence is that reptiles evolved to fill all ecological niches including the oceans (ichthyosaurs and plesiosaurs, turtles, and crocodilians), the skies (pterosaurs), and dominant land animals (dinosaurs).\n\nThey have given live birth (ichthyosaurs), they've been cold blooded and warm blooded (dinosaurs).\n\nI guess the point is that you could go simplistic and make your race not very far evolved from what we think of as reptiles (scaly skin which must be shed, egg laying, cold blooded, forked tongue (snakes)).\n\nOr you could make the race some step in some other direction, scales but with mammary glands, warm blooded, with feathers kind of like velociraptor.  Maybe they developed the truncated rib-cage like that of mammals which allows for tortional twists."\n\nWhat if monkeys were marsupial with scaley skin and they killed their prey by sepsis caused by the nasty bacteria that live in their mouth transfered when they bite their prey (like komodo dragons)?  What if these creatures were the progenitors of humanoid reptiles?
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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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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.