The Ojibwa of the forests of the eastern subarctic in Canada had this type of political organization. Throughout most of the year, families and small groups roamed from one hunting region to another. During summer months, the entire band came together on the shores of a lake and there performed various ritual feasts, and they also hunted as a larger group for the summer During this time, several men had influence and were political decision makers for the group as a hole. A number of other societies operate at this level, between having no identifiable political organization much of the time-and having political organization within the lineage Australian aborigines Australia is the only continent in the modern world to have been occupied exclusively by tribal foragers. Archaeologists have obtained absolute dates of 50,000-60,000 BP for human occupation in northern Australia using thermoluminescence Genetic evidence suggests that the ancestors of Australian aborigines must have come from S.E. Asia, but it will never be known precisely how they crossed the 44 mile stretch of open waterway that separated the closest Asian islands from Australia. This crossing likely occurred during the Ice Age when Australia and New Guinea were connected by the Sahul Shelf. Any evidence of migration there has been removed by rising waters Australia is the size of the U.S., but lacks any major rivers and mountains. It has been called the driest continent in the world. It is situated in the dry latitudes between the temperate and tropical zones, and rainfall is low and extremely variable. Aridity is the principal factor limiting the density and diversity of organisms, including foraging humans, throughout the continent. In the desert center, scarcity of water limits both plant and animal foods, and it determines human population movements and density. However, conditions are most extreme in the Western Desert, where there is no real seasonality or predictability in rainfall. Here, drought conditions may continue for years. People watch the clouds and rely on their detailed knowledge of the locations of specific rock holes and basins as they plan their nomadic movements. richard Gould states that population densities there are among the lowest for foragers in the world, verging less than 0.01 person per square kilometer. Joseph Birdsell has asserted that soon after immigration aborigines reached the maximum potential population that could be supported by their foraging technology throughout Australia and then maintained a constant balance between population and resources. Others say this balance was obtained more gradually Whatever the rate, it is accurate to say that human population densities varied directly with rainfall and were greatest in the biologically rich coastal regions, especially in the tropical north and east. Population densities remained quite low in the dry interior and in the west Because of the ratios of people to land, Australian aboriginal society offers a test case for the proposition that foraging peoples are(or were)more"in balance "with the environment than village farmers or large-scale societies. This adds to the thesis that the foraging way of life has existed much longer than any other Some scholars have noted the presence of infanticide among Australians, claiming that it was the