Dinosaur Age

this is a model of a dinosaur the dinosaurs were a group of reptils that disa from Earth at least 75 million years ago long before the first man appeared the word dinosaur means terrible lizard how do we know there were dinosaurs and how can we guess what they may have looked like let's see these paleontologists have come from a museum to look for the fossil bones of ancient reptils a paleontologist is a scientist who studies fossils fossils are the remains of plants and animals of past ages from previous fossil finds in this area they know that their chances of finding fossils are fairly good theyve found something some fossil bones embedded in rock they remove some of the overlying Rock and dirt so they can examine what they found their find is important enough to take back to the museum Laboratory first they clear the area being careful not to disturb the fossil remains now they begin the job covering the fossil bones they must work very carefully the dirt is removed a little at a time to reduce the danger of damaging the fine soon they are able to identify their find it's the paddle or flipper of aosa aaur was a large water living reptile or sea serpent closely related to the dinosaurs from the age of The Rock in it was found they know that this plesiosaur lived perhaps 100 million years ago when one side of the paddle has been cleared of dirt and rock the other side must be cut away so that the entire Rock slab with the bones in place can be lifted out the slab will be covered with a plaster cast so the bones can be moved without crumbling or breaking them first pieces of wet newspaper are used to cover the bone in order to protect them from the plaster then plaster of Paras is added to the water pieces of burlap are soaked in theaster of and carefully laid over the paper covered Bones the plaster soaked burlap will harden a strong cast when both sides have been covered with plaster a stick is placed along the length of the cast to prevent its breaking after the plaster hardens the plaur paddle with every bone in place is carried back to the museum at the Museum the paleontologists work in their laboratory on the job of preparing the fossil materials for study or exhibition carefully the cast is cut away great skill and Patience are needed the paper is lifted off the bones must be freed from the dirt and rock that still remain when the bones are clean enough a do of paint is placed on each one then they are numbered the paint and the numbers will make it easier for the paleontologist to put the bones together in their proper order after they are lifted from the finally when enough fossil bones of a plesiosaur have been gathered together an entire skelet is assembled the new paddle is put in its proper place the skeleton is mounted on iron supports to hold it in a natural position the bones of many animals collected over many years have been used to make this skeleton the shape of the bones and the position in which they may have been found helped the paleontologist in his job the Plesiosaurus skeleton has been put together as it must have been when the animal was alive sometimes the museum may decide that a model of the animal is needed a specially trained artist is called in the artist works with the paleontologist to make a sketch of the plaur skeleton from his sketch he makes a detailed and accurate drawing of the animal as it may have looked and from the artist drawing a model is finally completed in the same way models of other long dead animals like this brontosaurus are finally visitors to a museum may look at an exhibit like this one this brosaurus was a dinosaur probably the largest of all dinosaurs a model of a man built the scale will give you some idea of its size no man of course lived when the dinosaurs were alive brontosaurus was a plant eater some bravur weighed as much as 50 tons perhaps 10 times as much as a modern elephant and may have been 60 to 70 ft long the name brontosaurus means Thunder lizard it gets its name from the fact that when it walked it probably shook the Earth making a noise like thunder this is stegosaurus one of the smaller dinosaurs only 8T high and 15t long again the model man will give you an idea of its size stegosaurus too was a PL eater and the strange armor along its back was probably part of its defense against attacked by the larger more powerful flesh eaing dinosaur it Spike tail could have been a handy weapon too trodon is called the duck bill dinosaur it measured almost 30t from its head to its tail notice the scale model man again tradon walked upright it lived in the rivers and swamps of North America feeding upon water plants The Peculiar shape of its mouth gives it the name Duckville paleontologists believe it may have strained its food from the mud much as a modern duckes This Is tyrannosaurus the scale model Man shows you its great size for per the last Tyrannosaurus died about 100 million years before the first man appeared for Tyrannosaurus was the Tyrant lizard the most terrible of all the dinosaurs it skull measured more thanet in length it sharp pointed 6 in teeth prove it was a meat eater few animals probably could defend themselves against its attack the fossil bones of dinosaurs and other giant reptils have been found on every continent from fossils like these we know that dinosaurs ruled the Earth for over 100 million years only to Disappear Completely no one really knows why the dinosaurs and the other giant reptils are gone but today paleontologists and other scientists are continually searching for fossils in order to better understand the record of life on Earth [Music]