In recent decades, the amount of information available to researchers studying Pleistocene extinctions has grown substantially. With the exception of the development of a general consensus that human impacts, whether hunting or otherwise, regularly caused island extinctions, this dramatic increase in data has not led to a dramatic increase in conclusions about the cause (s) of Quaternary extinctions. The fundamental problem is that extinction hypotheses are very difficult to test directly, and they tend to be incredibly flexible, capable of accommodating virtually any evidence brought forth. For example, does a scarcity of archaeological evidence support or refute the overkill hypothesis? Unfortunately, there is no simple answer to that question. What has become increasingly clear is that a strong circumstantial case can be made for a significant human role in Quaternary extinctions, not only on islands but also on continents.
With the exception of Europe, Asia, and Africa, one could determine the timing of human colonization of virtually the entire world by studying only the palaeontological record. A wave of extinctions occurring within the last 50 000 years would indicate that humans had arrived. To many researchers, this evidence alone indicates clear human agency in Quaternary extinctions. If, however, islands are eliminated from this scenario, this temporal correlation only occurs on three large landmasses, North America, South America, and Australia, and perhaps it becomes more feasible to argue that these correlations are just coincidence. But extinctions on continents show consistent trends with respect to body size, disproportionately affecting the largest species, the preferred prey of hunter-gatherers. Yet if humans caused the continental extinctions of dozens of genera of Pleistocene fauna, must it have been the perfect crime? To kill these many animals and leave so little evidence, to some researchers seems like an impossible feat. To others, little evidence is expected. Such disagreements highlight why it has been so difficult to determine the causes of big game extinctions in the Quaternary.
See also: Archaeozoology; Butchery and Kill Sites; Migrations: Australia; Pacific; Modern Humans, Emergence of; New World, Peopling of; Oceania: Australia; Paleoenvironmental Reconstruction, Methods; Siberia, Peopling of.
World History
