File:The Australian Museum magazine (1921) (20162926390).jpg

Title: The Australian Museum magazine
Identifier: australianmuseum1192123aust (find matches)
Year: 1921 (1920s)
Authors: Australian Museum; Australian Museum
Subjects: Natural history
Publisher: Sydney, Australian Museum
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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THE AUSTRALIAN MUSEUM MAGAZINE 319
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The giant carnivorous Dinosaur, Tyrannosaurus, approaching Triceratops. a herbivorous relative on which it probably preyed. From a drawing by C. R. Knight. (Courtesy of the American Museum of Satnral History. EXTINCTION OF DINOSAURS. Many suggestions have been made to account for the extinction of these rep- tiles, which seem to have been built to endure for all time, but it is always difficult to discover the causes of ex- tinction of organic types. Looking down the great vista of the past we are apt to think that the dinosaurs evolved, reached their culmination, and then suddenly died out. But in reality the process was one of extreme slowness, spread over millions of years, and, once we realise that important fact, we cease to wonder at their disappearance. The great American naturalist. Cope, suggested that the small cunning mam- mals, which had already made their appearance before the Age of Reptiles drew to its close, would seek out and eat the eggs of their formidable contem- poraries. A more plausible explan- ation is that great geographical changes took place, the swamps necessary for some kinds of dinosaurs were drained by elevation of the land, aridity increased and the climate grew more severe. Reptiles as a class are more susceptible than birds or mammals to changes of temperature, for they are cold-blooded and have no covering of feathers or hair to protect them against cold. Then, too, the large size and over special- ization of many dinosaurs handicapped them for life's race. A large animal requires more food than a small one, and any considerable alteration in en- vironment is fatal to a creature which has become specially adapted to hve in a certain way and cannot adjust itself quickly enough to changed con- ditions. Palaeontology is continually enforcing the lesson that large size and extreme specialization almost always presage extinction. Professor T. Thomson Flynn, Liii- versity of Tasmania, Hobart, is at present carrying on certain investiga- tions relating to the internal organs of the Blue Tongue or Sleeping Lizards, a large well-known species belonging to the genus Tiliqua. As a large number of specimens is required, readers would be rendering a great service by send- ing any they may secure to the Aus- tralian Museum. It does not matter whether they be alive or dead so long as the abdominal organs are intact and uninjured.

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