Homo erectus also used more diverse and sophisticated tools than its predecessors. One theory is that H. erectus first used tools of the Oldowan style and then used tools of the Acheulean style. The surviving tools from both periods are all made of stone. Oldowan tools are the oldest known formed tools and date as far back as about 2.4 million year ago. The Acheulean era began about 1.2 million years ago and ended about 500,000 years ago. The primary innovation associated with Acheulean handaxes is that the stone was chipped on both sides to form two cutting edges.
There is some dispute as to whether H. erectus was able to control fire.