[.ca] Chasing Kangaroos: A Continent, a Scientist, and a ... (ISBN 0802118526)

Marsupial madness:
Among the world's landforms, Australia long has been the symbol of land mismanagement. Human intrusion has changed life's diversity nearly everywhere, but the demolition of the Island Continent's ecological balance has been particularly severe. Tim Flannery, although leaving an academic career in the humanities behind without losing his sense of it, gives an account of the condition of his native land. Although city-born and bred, Flannery had a deep urge to know the rest of his country better. Biology proved the gateway to that enterprise. In this compelling account of his quest and what he's learned on the journey, he depicts Australia as it is, and likely was in ancient times. Invasion has proved a major force. The author's search began one summer with an attempt to circuit Australia by motorcycle. Beset by numerous impediments, not the least of which was of spare parts for the bike, he finally abandoned that effort. As his career developed, he participated in numerous digs and analysis of fossil finds. Through this means the author hoped to derive a picture of kangaroo ancestry. On each trip to a dig, or working at the site, new people - often providing new information - come to his ken. Part of his search has been dedicated to meeting Aborigines, learning their ways, legends and history. With their long tenure in the Australian scene - longer than that of our species in Europe - their relationship with the land and its wildlife is an invaluable contribution. As Flannery learns, however, displacement by farmers and sheepmen have driven the Aborigines from their ancestral homes while killing off many of the native species. The catalogue of those creatures, extinct and remaining, provides the North American reader with some challenges. The euro and pademelon are not, respectively, a coin and a fruit - they are marsupial mammals. The quokka, one of the first Australian species described by Europeans, also provided the revelation that most of the marsupials have the ability to delay the birth of young. In stressful times, 'roos and the rest can signal the embryo to cease developing, restarting the process when resources are more plentiful. This is but one of numerous "adjustments" Australian wildlife makes in a harsh environment. Others are due to environmental shifts caused by human intrusion. The euro, for example, able to live almost without water, repopulates areas where its larger cousins have been exterminated by hunters. They are thus fierce competitors to the ubiquitous, and profitable, sheep, adapting to the changes in environment instilled by European invaders. Australia's fossils are difficult to date. In its geological dance over the aeons, there was little volcanic activity in the Centre to provide dateable rocks. Although the world's oldest rocks, from 4.2 billion years ago are from there, younger, fossil-bearing strata must be approximately dated. Flannery's aim to build a picture of kangaroo evolution is hampered by this reality. Such impediments don't deter Flannery as he collects information to build a picture of marsupial evolution. The results lack the precision that some other lineages enjoy, but the image is better than it was when he began his search. The relative times and locations of the origins of marsupials and placentals \ocreatures like us that lack the nursery of a pouch\c is now clear. Flannery explains how an unexpected discovery at Flat Rocks revealed the presence of placentals many millions of years old. The find overturned the long-held notion that placentals emerged in the northern hemisphere. Science never rests, and Flannery's book demonstrates how many areas remain open to further investigation. \ostephen a. haines - Ottawa, Canada\c