"Boaz and Ciochon take readers on a gripping scientific odyssey. New evidence shows that Homo erectus was an opportunist who rode a tide of environmental change out of Africa and into Eurasia, puddle-jumping from one gene pool to the next. Armed with a shaky hold on fire and some sharp rocks, Homo erectus incredibly survived for over 1.5 million years, much longer than our own species Homo sapiens has been on Earth. Tell-tale marks on fossil bones show that the lives of these early humans were brutal, ruled by hunger and who could strike the hardest blow, yet there are fleeting glimpses of human compassion as well. The small brain of Homo erectus and its strangely unchanging culture indicate that the species could not talk. Part of that primitive culture included ritualized aggression, to which the extremely thick skulls of Homo erectus bear mute witness."--Jacket.