Megafauna

Ecological competition began as slow arms races. Predators evolved to hunt. Preyevolved to defend themselves. Each improvement was small, barely shifting the oddsof survival. Nature remained in equilibrium. Until the dawn of humanity. When ourancestors developed the unique ability to think up new devices and behaviors,humanity became able to overcome nature''s defenses far more quickly than naturalselection could respond. Humankind spread out of Africa, wiping out most of themegafauna in its path—mammoths, sabertooth cats, elephant-sized sloths, and a greatmany other species. Today, this formidable, inventive genius of our species—nowgrown to overwhelming and all-conquering proportions—is threatening to make theearth unlivable, even for ourselves. The only weapon available to us to counter thisthreat is, ironically, the same one that unleashed our destructiveness in the firstplace: the analytical and creative power of the human brain.