SALT LAKE CITY, UTAH—According to a Cosmos Magazine report, environmental changes are more likely to have wiped out Africa’s megafauna than is hunting by Homo
erectus, which emerged some 1.9 million years ago and has previously been blamed for causing the extinctions. Paleoecologist Tyler Faith of the University of Utah and his colleagues examined more than 100 fossil assemblages spanning the past seven million years found in Kenya, Tanzania, and Ethiopia. The researchers found that African megafauna species of elephants, hippos, rhinoceroses, giraffes, and camels began to decline some 4.6 million years ago, or about 2.5 million years before the arrival of H. erectus. Faith adds that the rate of extinction did not accelerate when H. erectus finally emerged. Analysis of climate data, changes in soil chemistry, and trace elements in animal teeth suggests that a global drop in levels of atmospheric carbon dioxide led to expansion of grasslands and loss of forests and woody vegetation that the large-bodied mammals relied upon for food. “It’s really a long-term ecological process that’s really difficult to pin on increased carnivory by the tool-using, meat-eating hominids,” Faith said. For more, go to “Homo erectus Stands Alone.”