MARSUPIALS,++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++MORE+INFORMATION+ABOUT+MARSUPIALS

=Marsupials are the group of mammals commonly thought of as pouched mammals (like the wallaby and kangaroo at left).= =They give live birth, but they do not have long gestation times like [|placental mammals]. Instead, they give birth very early and the young animal, essentially a helpless embryo, climbs from the mother's birth canal to the nipples.There= = Red-necked Wallaby. Photo by Gerald and Buff Corsi, © 2002 California Academy of Sciences. = = = || == || == = Red Kangaroo. Photo by Gerald and Buff Corsi, © 2002 California Academy of Sciences. = = = || == || =it grabs on with its mouth and continues to develop, often for weeks or months depending on the species. The short gestation time is due to having a yolk-type placenta in the mother marsupial. Placental mammals nourish the developing embryo using the mother's blood supply, allowing longer gestation times.= =Like other mammals, the marsupials are covered with hair. Mothers nurse their young — a young kangaroo may nurse even when it has grown almost to the mother's size.= =The only naturally occurring marsupial in the United States is the opossum, //Didelphis virginiana//. In the past, however, marsupials were quite common.= = Koala. Photo by Gerald and Buff Corsi, © 2002 California Academy of Sciences. = = = || == || == = Wombat. Photo © 2005 Sharon Chester. = = = || == || =In South America and Australia, however, marsupials continued to be an important group of land mammals. Many South American forms are similar to the North= = //Thylacinus//, an extinct marsupial wolf. = = = || = =
 * =[[image:http://www.ucmp.berkeley.edu/mammal/marsupial/wallaby.jpg width="170" height="250" caption="Red-necked Wallaby"]]=
 * =[[image:http://www.ucmp.berkeley.edu/mammal/marsupial/koala.jpg width="213" height="250" caption="Koala"]]=
 * =[[image:http://www.ucmp.berkeley.edu/images/dot_clear.gif width="10" height="1"]]= || =[[image:http://www.ucmp.berkeley.edu/mammal/marsupial/marsupialwolf.jpg width="300" height="163" caption="Marsupial wolf"]]=

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