One million years ago, elephants and their cousins roamed the five major continents of the earth. Then humans came along. Today elephants can be found only in portions of sub-Saharan Africa and South Asia.There is a long-running debate over what drove elephants to extinction in some parts of the world and completely wiped other two other proboscideans, mammoths and mastodons.The two most argued hypotheses for their decline are climatic changes and over-hunting by humans. A recent archaeological expedition dug up information that may support the latter.Exploring 41 sites ranging from 1.8 million to 10,000 years old, Todd Surovell of the University of Wyoming found that interactions between humans and elephants matched up with successive waves of human population expansion. As the human populations in those sites continued to grow, the number of elephants shrank and, in some sites, disappeared.The findings suggest that the geographic expansion of prehistoric humans resulted in localized extinction events. Over-hunting was a key factor in these extinctions, Surovell figures, but range fragmentation likely played a role too.
View: Full Article | Source: Yahoo! News