While the earliest H. erectus specimens are found in association with very basic stone tools, typically referred to as the Oldowan stone tool industry, by 1.5 million years ago populations of H. erectus were creating a more complex and typologically codified set of tools that we refer to as the Acheulean industry (Bar-Yosef & Belfer-Cohen 2001).
The intensified niche goes hand in hand with the expansion in brain and body size. Larger bodies, and longer limbs in particular, increase locomotor efficiency (Pontzer et al. 2010). Homo erectus could cover more ground on a day-to-day basis, through walking or running, than smaller hominins and with lower energy cost. In addition, the larger brain gave these hominins better capabilities for processing complex ecological information across the more expansive terrain containing higher quality food items. For example, there is clear evidence of H. erectus accessing medium- and large-sized animal carcasses for meat, through hunting and/or scavenging, in the form of fossil remains of animals with cut marks left by butchery. This behavior, regularly accessing animal carcasses, is an ecological change from earlier hominins (Link to Pobiner's NKP article). While the earliest H. erectus specimens are found in association with very basic stone tools, typically referred to as the Oldowan stone tool industry, by 1.5 million years ago populations of H. erectus were creating a more complex and typologically codified set of tools that we refer to as the Acheulean industry (Bar-Yosef & Belfer-Cohen 2001).